2019 Vol. 36, No. 11
2019, 36(11): 2487-2494.
doi: 10.13801/j.cnki.fhclxb.20190123.002
Abstract:
To explore the suitable surface treatment method of carbon fiber and improve the interface bonding effect of carbon fiber fabric reinforced nylon 6 composites, carbon fiber-nylon 6 preforms were prepared by mixing braid, and the preform was socked in different concentrations of alcohol-soluble nylon anhydrous ethanol solution, and finally the carbon fiber fabric-nylon 6 composite was prepared by hot pressing. The mechanical properties, microstructure, heat resistance, crystallinity and crystal form of the carbon fiber fabric-nylon 6 composite were analyzed by universal tensile testing machine, SEM, TGA, DSC and XRD. The results indicate that when preforms are socked at 1wt% alcohol-soluble nylon anhydrous ethanol solution, the carbon fiber fabric-nylon 6 composites have the best mechanical properties, the tensile strength, elastic modulus, bending strength, flexural modulus and impact strength are 449.32 MPa, 5.32 GPa, 657.67 MPa, 44.08 GPa and 138.42 kJ/m2, respectively. After the fiber is pulled out, a part of the nylon matrix is adhered to the surface of the single carbon fiber, and the carbon fiber and the nylon matrix form a good interface layer. Compared with nylon 6 fiber, the initial decomposition temperature of carbon fiber fabric-nylon 6 composite material is increased by 13℃, and the heat resistance is enhanced. The nylon 6 resin mainly exists in α crystal form, and the crystallization is perfect.
To explore the suitable surface treatment method of carbon fiber and improve the interface bonding effect of carbon fiber fabric reinforced nylon 6 composites, carbon fiber-nylon 6 preforms were prepared by mixing braid, and the preform was socked in different concentrations of alcohol-soluble nylon anhydrous ethanol solution, and finally the carbon fiber fabric-nylon 6 composite was prepared by hot pressing. The mechanical properties, microstructure, heat resistance, crystallinity and crystal form of the carbon fiber fabric-nylon 6 composite were analyzed by universal tensile testing machine, SEM, TGA, DSC and XRD. The results indicate that when preforms are socked at 1wt% alcohol-soluble nylon anhydrous ethanol solution, the carbon fiber fabric-nylon 6 composites have the best mechanical properties, the tensile strength, elastic modulus, bending strength, flexural modulus and impact strength are 449.32 MPa, 5.32 GPa, 657.67 MPa, 44.08 GPa and 138.42 kJ/m2, respectively. After the fiber is pulled out, a part of the nylon matrix is adhered to the surface of the single carbon fiber, and the carbon fiber and the nylon matrix form a good interface layer. Compared with nylon 6 fiber, the initial decomposition temperature of carbon fiber fabric-nylon 6 composite material is increased by 13℃, and the heat resistance is enhanced. The nylon 6 resin mainly exists in α crystal form, and the crystallization is perfect.
2019, 36(11): 2495-2501.
doi: 10.13801/j.cnki.fhclxb.20190228.001
Abstract:
A new type of graphene oxide-acylase (GO-acylase) nanoparticles was produced via an electrostatic force. The GO and GO-acylase were added to the poly(vinylidene fluoride) (PVDF) membrane casting solution respectively, and the GO/PVDF and GO-acylase/PVDF composite membranes were prepared through phase inversion by the immersion precipitation technique. The results show that the surface roughness of GO-acylase/PVDF membrane is very smooth (Ra=8.21 nm), and the contact angles of GO/PVDF and GO-acylase/PVDF membranes are relatively lower (73.72° and 71.31°), which indicates that the hydrophilicity of composite membranes are better than that of pristine PVDF membrane. The addition of GO enhances the transformation process between solute and insoluble, which results in the highest pure water flux (69.0 L/(m2h)) of GO/PVDF membrane. The biological activity of GO-acylase/PVDF membrane can be maintained for about 4 weeks, which indicates that the new GO-acylase/PVDF membrane is prepared successfully, and provides a new way to mitigate the bio-fouling of membrane.
A new type of graphene oxide-acylase (GO-acylase) nanoparticles was produced via an electrostatic force. The GO and GO-acylase were added to the poly(vinylidene fluoride) (PVDF) membrane casting solution respectively, and the GO/PVDF and GO-acylase/PVDF composite membranes were prepared through phase inversion by the immersion precipitation technique. The results show that the surface roughness of GO-acylase/PVDF membrane is very smooth (Ra=8.21 nm), and the contact angles of GO/PVDF and GO-acylase/PVDF membranes are relatively lower (73.72° and 71.31°), which indicates that the hydrophilicity of composite membranes are better than that of pristine PVDF membrane. The addition of GO enhances the transformation process between solute and insoluble, which results in the highest pure water flux (69.0 L/(m2h)) of GO/PVDF membrane. The biological activity of GO-acylase/PVDF membrane can be maintained for about 4 weeks, which indicates that the new GO-acylase/PVDF membrane is prepared successfully, and provides a new way to mitigate the bio-fouling of membrane.
2019, 36(11): 2502-2508.
doi: 10.13801/j.cnki.fhclxb.20190412.003
Abstract:
The Ag-carried tetracycline-mulberry bast carboxymethyl cellulose/polyvinyl alcohol(Ag-T-CMC/PVA)composite films were prepared by solution casting method. And the structure and properties of Ag-T-CMC/PVA composite films were investigated by XRD, SEM and DSC. The results show that with the increase of Ag-T-CMC content, the mechanical properties, water resistance and antibacterial properties of Ag-T-CMC/PVA composite films are improved. When the mass ratio of Ag-T-CMC to PVA is 2%, the mechanical properties of the Ag-T-CMC/PVA composite film are the best and the tensile strength increases by 3.4%. SEM analysis shows that Ag-T-CMC is uniformly dispersed in Ag-T-CMC/PVA composite films, showing good compatibility, and with the increasing Ag-T-CMC content, the faults gradually become smooth plane. When the mass ratio of Ag-T-CMC to PVA is 2%, the faults are the smoothest. The water absorption test shows that Ag-T-CMC can significantly reduce the water absorption of Ag-T-CMC/PVA composite films. The antibacterial test shows that the Ag-T-CMC/PVA composite films have certain antibacterial effect on Escherichia coli and Staphylococcus aureus, and with the increase of Ag-T-CMC content, the diameter of the antibacterial circle becomes larger and the antibacterial effect is enhanced.
The Ag-carried tetracycline-mulberry bast carboxymethyl cellulose/polyvinyl alcohol(Ag-T-CMC/PVA)composite films were prepared by solution casting method. And the structure and properties of Ag-T-CMC/PVA composite films were investigated by XRD, SEM and DSC. The results show that with the increase of Ag-T-CMC content, the mechanical properties, water resistance and antibacterial properties of Ag-T-CMC/PVA composite films are improved. When the mass ratio of Ag-T-CMC to PVA is 2%, the mechanical properties of the Ag-T-CMC/PVA composite film are the best and the tensile strength increases by 3.4%. SEM analysis shows that Ag-T-CMC is uniformly dispersed in Ag-T-CMC/PVA composite films, showing good compatibility, and with the increasing Ag-T-CMC content, the faults gradually become smooth plane. When the mass ratio of Ag-T-CMC to PVA is 2%, the faults are the smoothest. The water absorption test shows that Ag-T-CMC can significantly reduce the water absorption of Ag-T-CMC/PVA composite films. The antibacterial test shows that the Ag-T-CMC/PVA composite films have certain antibacterial effect on Escherichia coli and Staphylococcus aureus, and with the increase of Ag-T-CMC content, the diameter of the antibacterial circle becomes larger and the antibacterial effect is enhanced.
2019, 36(11): 2509-2514.
doi: 10.13801/j.cnki.fhclxb.20190314.001
Abstract:
The TiO2/polyethylene terephthalate (PET) nonwoven was prepared by TiO2-loaded on the recycled PET nonwoven fabric. The PET nonwoven fabric was firstly treated by alkali etching and the TiO2 was obtained by hydrolysis reaction of tetrabutyl titanate (TBT). The uniform TiO2 particles can be observed through SEM when the TBT content is 6wt%. The influence of the alkali etching temperature and TBT content on the mechanical property of PET and TiO2/PET nonwoven fabric was investigated. The results show that the alkali reduction increases and the tenacity of PET nonwoven fabric gradually decreases with the increasing of alkali etching temperature. The tenacity of the nonwoven fabric by etching at 60℃ and 80℃ is comparable at the same TBT content, because the formation of the loaded TiO2 improves the mechanical properties of the TiO2/PET nonwoven fabric. The tenacity of TiO2/PET nonwoven fabric increases firstly and then decreases with TBT content increasing. The TBT content that corresponding to the maximum tenacity increases with the increase of temperature. In order to character the photocatalytic self-cleaning properties of TiO2/PET nonwoven fabric, methyl orange solution was used as a degradation substance, TiO2/PET nonwoven fabric was treated under ultraviolet light with 30 W, and the apparent depth of color was tested using a colorimeter. The results show that the photo degradation performance is the best when the alkali etching temperature is 80℃ and TBT content is 6wt%, the degradation of methyl orange solution is 89.05% and this ratio just decreases 1.43% after five cycles. The results are all attribute to the higher special surface area and the formation of uniform TiO2 on the PET fiber surface at 80℃ and 6wt% TBT.
The TiO2/polyethylene terephthalate (PET) nonwoven was prepared by TiO2-loaded on the recycled PET nonwoven fabric. The PET nonwoven fabric was firstly treated by alkali etching and the TiO2 was obtained by hydrolysis reaction of tetrabutyl titanate (TBT). The uniform TiO2 particles can be observed through SEM when the TBT content is 6wt%. The influence of the alkali etching temperature and TBT content on the mechanical property of PET and TiO2/PET nonwoven fabric was investigated. The results show that the alkali reduction increases and the tenacity of PET nonwoven fabric gradually decreases with the increasing of alkali etching temperature. The tenacity of the nonwoven fabric by etching at 60℃ and 80℃ is comparable at the same TBT content, because the formation of the loaded TiO2 improves the mechanical properties of the TiO2/PET nonwoven fabric. The tenacity of TiO2/PET nonwoven fabric increases firstly and then decreases with TBT content increasing. The TBT content that corresponding to the maximum tenacity increases with the increase of temperature. In order to character the photocatalytic self-cleaning properties of TiO2/PET nonwoven fabric, methyl orange solution was used as a degradation substance, TiO2/PET nonwoven fabric was treated under ultraviolet light with 30 W, and the apparent depth of color was tested using a colorimeter. The results show that the photo degradation performance is the best when the alkali etching temperature is 80℃ and TBT content is 6wt%, the degradation of methyl orange solution is 89.05% and this ratio just decreases 1.43% after five cycles. The results are all attribute to the higher special surface area and the formation of uniform TiO2 on the PET fiber surface at 80℃ and 6wt% TBT.
2019, 36(11): 2515-2521.
doi: 10.13801/j.cnki.fhclxb.20190401.003
Abstract:
The sulfonated graphene oxide/polysulfone (SGO/PSf) composite membranes were prepared by immersion precipitation-phase inversion method. The hydrophilicity, water flux, porosity, surface Zeta potential, membrane cross section and surface morphology of SGO/PSf composite membranes were measured in detail. In order to analysis the antifouling of membranes, the adhesion forces between SGO/PSf composite membranes and bovine serum albumin (BSA) were measured by atomic force microscopy (AFM) with self-made BSA probes. The experimental results show that the SGO/PSf composite membrane with 0.50wt% SGO has the largest surface free energy (114.47 mJ/m2) and the best hydrophilicity, due to the synergistic effect of SGO and polyvinylpyrrolidone (PVP). The rejection rate of SGO/PSf composite membrane to BSA is 97.5%, and the fouling recovery rate is 80.06%. The adhesion force between BSA and membrane is the least (-0.61 mN/m), which illustrates that the antifouling ability of the SGO/PSf composite membrane with 0.50wt% SGO is the best.
The sulfonated graphene oxide/polysulfone (SGO/PSf) composite membranes were prepared by immersion precipitation-phase inversion method. The hydrophilicity, water flux, porosity, surface Zeta potential, membrane cross section and surface morphology of SGO/PSf composite membranes were measured in detail. In order to analysis the antifouling of membranes, the adhesion forces between SGO/PSf composite membranes and bovine serum albumin (BSA) were measured by atomic force microscopy (AFM) with self-made BSA probes. The experimental results show that the SGO/PSf composite membrane with 0.50wt% SGO has the largest surface free energy (114.47 mJ/m2) and the best hydrophilicity, due to the synergistic effect of SGO and polyvinylpyrrolidone (PVP). The rejection rate of SGO/PSf composite membrane to BSA is 97.5%, and the fouling recovery rate is 80.06%. The adhesion force between BSA and membrane is the least (-0.61 mN/m), which illustrates that the antifouling ability of the SGO/PSf composite membrane with 0.50wt% SGO is the best.
2019, 36(11): 2522-2529.
doi: 10.13801/j.cnki.fhclxb.20190123.001
Abstract:
The main obstacle of wide commercialization of proton exchange membrane is to maintain the high conductivity and low swelling ratio of proton exchange membrane at higher temperature under fully hydrated state. In order to solve this issue, by using poly-dopamine (PDA) as an intermediate layer, ZrO2 was formed on the commercial sulfonated polysulfone (PSF) porous membrane matrix, a facial approach of preparing well performed composite proton exchange membrane was proposed. The influence of PDA deposition conditions and ZrO2 mineralization process on the surface morphology and element distribution of PSF-PDA-ZrO2 composite membrane were investigated. The PSF-PDA modified membrane with PDA deposition time of 5 h was selected for mineralization. It is found that the content of Zr element on the surface mineralized layer of PSF-PDA-ZrO2 composite membranes is significantly increased with increasing mineralization time. The water uptake, swelling ratio and proton conductivity of PSF-PDA-ZrO2 composite membrane were tested. The results show that the surface of ZrO2 mineralized layer significantly inhibits the swelling ratio of PSF-PDA-ZrO2 composite membranes at higher temperature compared with PSF porous membranes, and the swelling ratio of composite membranes gradually reduces with the increase of ZrO2 mineralization time. The proton conductivity of PSF-PDA-ZrO2 composite membranes with mineralization time for 1 h, 5 h, 12 h and 24 h is higher than that of the pure PSF porous membrane, and the conductivity of the PSF-PDA-ZrO2 composite membranes decreases gradually with the increase of mineralization time. The proton conductivity of PSF-PDA-ZrO2 composite membrane after PDA deposition for 5 h and mineralization for 1 h is up to 0.117 Scm-1 at 90℃, which is 2.5 times of the PSF porous basement membrane.
The main obstacle of wide commercialization of proton exchange membrane is to maintain the high conductivity and low swelling ratio of proton exchange membrane at higher temperature under fully hydrated state. In order to solve this issue, by using poly-dopamine (PDA) as an intermediate layer, ZrO2 was formed on the commercial sulfonated polysulfone (PSF) porous membrane matrix, a facial approach of preparing well performed composite proton exchange membrane was proposed. The influence of PDA deposition conditions and ZrO2 mineralization process on the surface morphology and element distribution of PSF-PDA-ZrO2 composite membrane were investigated. The PSF-PDA modified membrane with PDA deposition time of 5 h was selected for mineralization. It is found that the content of Zr element on the surface mineralized layer of PSF-PDA-ZrO2 composite membranes is significantly increased with increasing mineralization time. The water uptake, swelling ratio and proton conductivity of PSF-PDA-ZrO2 composite membrane were tested. The results show that the surface of ZrO2 mineralized layer significantly inhibits the swelling ratio of PSF-PDA-ZrO2 composite membranes at higher temperature compared with PSF porous membranes, and the swelling ratio of composite membranes gradually reduces with the increase of ZrO2 mineralization time. The proton conductivity of PSF-PDA-ZrO2 composite membranes with mineralization time for 1 h, 5 h, 12 h and 24 h is higher than that of the pure PSF porous membrane, and the conductivity of the PSF-PDA-ZrO2 composite membranes decreases gradually with the increase of mineralization time. The proton conductivity of PSF-PDA-ZrO2 composite membrane after PDA deposition for 5 h and mineralization for 1 h is up to 0.117 Scm-1 at 90℃, which is 2.5 times of the PSF porous basement membrane.
2019, 36(11): 2530-2540.
doi: 10.13801/j.cnki.fhclxb.20190326.002
Abstract:
Using micro Mg(OH)2 (mMg(OH)2), nano Mg(OH)2 (nMg(OH)2) and microencapsulated red phosphorus (MRP) as the halogen-free flame retardants and ethylene-vinyl acetate copolymer (EVA) as the polymer matrix, a series of Mg(OH)2-MRP/EVA flame-retardant composites with different loadings of flame retardant were prepared by melt-compounding. The flame retardancy, mechanical and processing properties of the Mg(OH)2-MRP/EVA composites were investigated by limiting oxygen index, vertical burning test, cone calorimetry, thermal analysis, SEM, tensile test and rheological analysis. The results indicate that both flame retardancy and smoke suppression of the nMg(OH)2/EVA composite are better than that of the mMg(OH)2/EVA composite at the same loading of Mg(OH)2 flame retardant. However, the UL-94 rating of nMg(OH)2/EVA and mMg(OH)2/EVA composites can not reach V-0 rating when the Mg(OH)2 loading is less than 60wt%. The flame retardant efficiency of Mg(OH)2 is low by itself and there is remarkable synergism between nMg(OH)2 and MRP on the flame retardancy of EVA. The loading of Mg(OH)2 can be reduced considerably when nMg(OH)2 and MRP are combined at proper ratio. Comparing with nMg(OH)2/EVA composite, the nMg(OH)2-MRP/EVA composite can produce a continuous and compact char residue layer on its surface, which serves as a barrier against fire and increases fire retardancy. The thermal degradation of nMg(OH)2 has crucial influence on the fire behavior of the nMg(OH)2-MRP/EVA composite. When nMg(OH)2 is pre-pyrolyzed and added to the MRP/EVA composite, both flame retardancy and smoke suppression of the obtained nMg(OH)2-MRP/EVA composite decline sharply. When the mass ratio of nMg(OH)2:MRP:EVA is 40:10:100, the obtained nMg(OH)2-MRP/EVA composite shows excellent flame retardant, mechanical and processing properties simultaneously, which can meet the demand of practical applications.
Using micro Mg(OH)2 (mMg(OH)2), nano Mg(OH)2 (nMg(OH)2) and microencapsulated red phosphorus (MRP) as the halogen-free flame retardants and ethylene-vinyl acetate copolymer (EVA) as the polymer matrix, a series of Mg(OH)2-MRP/EVA flame-retardant composites with different loadings of flame retardant were prepared by melt-compounding. The flame retardancy, mechanical and processing properties of the Mg(OH)2-MRP/EVA composites were investigated by limiting oxygen index, vertical burning test, cone calorimetry, thermal analysis, SEM, tensile test and rheological analysis. The results indicate that both flame retardancy and smoke suppression of the nMg(OH)2/EVA composite are better than that of the mMg(OH)2/EVA composite at the same loading of Mg(OH)2 flame retardant. However, the UL-94 rating of nMg(OH)2/EVA and mMg(OH)2/EVA composites can not reach V-0 rating when the Mg(OH)2 loading is less than 60wt%. The flame retardant efficiency of Mg(OH)2 is low by itself and there is remarkable synergism between nMg(OH)2 and MRP on the flame retardancy of EVA. The loading of Mg(OH)2 can be reduced considerably when nMg(OH)2 and MRP are combined at proper ratio. Comparing with nMg(OH)2/EVA composite, the nMg(OH)2-MRP/EVA composite can produce a continuous and compact char residue layer on its surface, which serves as a barrier against fire and increases fire retardancy. The thermal degradation of nMg(OH)2 has crucial influence on the fire behavior of the nMg(OH)2-MRP/EVA composite. When nMg(OH)2 is pre-pyrolyzed and added to the MRP/EVA composite, both flame retardancy and smoke suppression of the obtained nMg(OH)2-MRP/EVA composite decline sharply. When the mass ratio of nMg(OH)2:MRP:EVA is 40:10:100, the obtained nMg(OH)2-MRP/EVA composite shows excellent flame retardant, mechanical and processing properties simultaneously, which can meet the demand of practical applications.
2019, 36(11): 2541-2551.
doi: 10.13801/j.cnki.fhclxb.20190401.002
Abstract:
The development of high voltage direct current (HVDC) transmission is limited on account of the space charge accumulation in HVDC insulation. The effects of nano SiO2, micro SiO2, micro and nano SiO2 and the preparation process on the space charge behavior in SiO2/low density polyethylene (LDPE) composites were investigated. The microstructure and crystallization characteristics of different SiO2/LDPE composites were characterized by SEM, FTIR and DSC. The trap characteristics of SiO2/LDPE composites were studied using thermally stimulated current (TSC). The space charge behavior in the pure LDPE and SiO2/LDPE composites were investigated by electro-acoustic pulse (PEA) technique. The results show that the grain size of LDPE is reduced by the introduction of SiO2, and the crystallinity is increased. The area under TSC curves of SiO2/LDPE composites increases, the TSC peaks of micro SiO2/LDPE composites shift to lower temperature, and those of SiO2/LDPE composites with nano SiO2 move higher temperature. All SiO2/LDPE composites exhibit the effect inhibiting space charge to some extent. The preparation process of micro and nano SiO2/LDPE composite has certain influence on its performance. When the micro and nano SiO2/LDPE composite is prepared in the form of masterbatch, its performance is closer to the composite corresponding to the inorganic particles added later.
The development of high voltage direct current (HVDC) transmission is limited on account of the space charge accumulation in HVDC insulation. The effects of nano SiO2, micro SiO2, micro and nano SiO2 and the preparation process on the space charge behavior in SiO2/low density polyethylene (LDPE) composites were investigated. The microstructure and crystallization characteristics of different SiO2/LDPE composites were characterized by SEM, FTIR and DSC. The trap characteristics of SiO2/LDPE composites were studied using thermally stimulated current (TSC). The space charge behavior in the pure LDPE and SiO2/LDPE composites were investigated by electro-acoustic pulse (PEA) technique. The results show that the grain size of LDPE is reduced by the introduction of SiO2, and the crystallinity is increased. The area under TSC curves of SiO2/LDPE composites increases, the TSC peaks of micro SiO2/LDPE composites shift to lower temperature, and those of SiO2/LDPE composites with nano SiO2 move higher temperature. All SiO2/LDPE composites exhibit the effect inhibiting space charge to some extent. The preparation process of micro and nano SiO2/LDPE composite has certain influence on its performance. When the micro and nano SiO2/LDPE composite is prepared in the form of masterbatch, its performance is closer to the composite corresponding to the inorganic particles added later.
2019, 36(11): 2552-2560.
doi: 10.13801/j.cnki.fhclxb.20190320.002
Abstract:
The short carbon fiber-carbon nanotubes/polydimethylsiloxane (SCF-CNTs/PDMS) conductive compo-sites were prepared by spatial confining forced network assembly (SCFNA) method. The influence of SCF-CNTs/PDMS composites prepared by SCFNA method on the morphology, electrical conductivity and mechanical properties of the sections was studied. The results show that a dense and effective conductive network is obtained by preparing the SCF-CNTs/PDMS conductive composites by SCFNA method. The electrical conductivity and mechanical properties of the SCF-CNTs/PDMS composite are increased with low concentration fillers due to the shortened distance between the conductive fillers. Add a small amount of CNTs to SCF/PDMS with the same amount of filler, a good synergy between SCF and CNTs can be formed. The performance of SCF-CNTs/PDMS composite (the mass fraction of SCF is 8wt%, the mass fraction of CNTs is 2wt%) is found to be 33% higher in conductive properties and 144% higher in mechanical properties than the SCF/PDMS composite (the mass fraction of SCF is 10wt%). More CNTs have been added to SCF/PDMS composite. Due to the agglomeration between CNTs, the electrical and mechanical properties of the SCF-CNTs/PDMS composites decrease; as the mixing speed gradually increases from 40 r/min to 80 r/min, the CNTs agglomeration phenomenonin in the SCF-CNTs/PDMS composite(the mass fraction of SCF is 5wt%, the mass fraction of CNTs is 5wt%) is improved. Due to the increase of torque, the shearing force of the SCF is increased, and most of the SCF is crushed. In conductive composites, SCF acts as a primary connection to the conductive network. Therefore, the conductivity of SCF-CNTs/PDMS composite (the mass fraction of SCF is 5wt%, the mass fraction of CNTs is 5wt%) decreases with the increase of the mixing speed.
The short carbon fiber-carbon nanotubes/polydimethylsiloxane (SCF-CNTs/PDMS) conductive compo-sites were prepared by spatial confining forced network assembly (SCFNA) method. The influence of SCF-CNTs/PDMS composites prepared by SCFNA method on the morphology, electrical conductivity and mechanical properties of the sections was studied. The results show that a dense and effective conductive network is obtained by preparing the SCF-CNTs/PDMS conductive composites by SCFNA method. The electrical conductivity and mechanical properties of the SCF-CNTs/PDMS composite are increased with low concentration fillers due to the shortened distance between the conductive fillers. Add a small amount of CNTs to SCF/PDMS with the same amount of filler, a good synergy between SCF and CNTs can be formed. The performance of SCF-CNTs/PDMS composite (the mass fraction of SCF is 8wt%, the mass fraction of CNTs is 2wt%) is found to be 33% higher in conductive properties and 144% higher in mechanical properties than the SCF/PDMS composite (the mass fraction of SCF is 10wt%). More CNTs have been added to SCF/PDMS composite. Due to the agglomeration between CNTs, the electrical and mechanical properties of the SCF-CNTs/PDMS composites decrease; as the mixing speed gradually increases from 40 r/min to 80 r/min, the CNTs agglomeration phenomenonin in the SCF-CNTs/PDMS composite(the mass fraction of SCF is 5wt%, the mass fraction of CNTs is 5wt%) is improved. Due to the increase of torque, the shearing force of the SCF is increased, and most of the SCF is crushed. In conductive composites, SCF acts as a primary connection to the conductive network. Therefore, the conductivity of SCF-CNTs/PDMS composite (the mass fraction of SCF is 5wt%, the mass fraction of CNTs is 5wt%) decreases with the increase of the mixing speed.
2019, 36(11): 2561-2567.
doi: 10.13801/j.cnki.fhclxb.20190121.001
Abstract:
The single bamboo fiber-bamboo fiber sheath/polypropylene (SBF-BFS/PP) composites, in which PP as substrate and SBF along with BFS as two kinds of reinforcements, were fabricated by non-woven airflow paving-moulding process. To investigate the contents of two kinds of bamboo fiber on the comprehensive properties of SBF-BFS/PP composites, the mechanical properties, microstructure and thermal properties of the SBF-BFS/PP composites were characterized by mechanical testing machine, SEM, TGA and DSC. The results show that the impact strength and elastic modulus of the SBF-BFS/PP composites increase gradually with increasing the contents of the SBF in the two forms of bamboo fibers under the contents of PP fiber keeping constant. Compared with the SBF-BFS/PP composite containing 10wt% SBF in SBF-BFS, the impact strength and elastic modulus of the SBF-BFS/PP composite with 90wt% SBF in SBF-BFS increases by 26.46% and 38.39%, respectively. SEM results show that the interfacial compatibility between bamboo fiber and PP matrix is poor, and the bamboo fiber is broken and pulled out. TGA results show that the thermal resistance of SBF-BFS/PP composites exhibit no obvious changes. The water resistance of SBF-BFS/PP composites show that, due to the large specific surface area of SBF, the water absorbent components in the SBF-BFS/PP composites increase with the increase of SBF content, leading to the decline of the water resistance of the SBF-BFS/PP composites.
The single bamboo fiber-bamboo fiber sheath/polypropylene (SBF-BFS/PP) composites, in which PP as substrate and SBF along with BFS as two kinds of reinforcements, were fabricated by non-woven airflow paving-moulding process. To investigate the contents of two kinds of bamboo fiber on the comprehensive properties of SBF-BFS/PP composites, the mechanical properties, microstructure and thermal properties of the SBF-BFS/PP composites were characterized by mechanical testing machine, SEM, TGA and DSC. The results show that the impact strength and elastic modulus of the SBF-BFS/PP composites increase gradually with increasing the contents of the SBF in the two forms of bamboo fibers under the contents of PP fiber keeping constant. Compared with the SBF-BFS/PP composite containing 10wt% SBF in SBF-BFS, the impact strength and elastic modulus of the SBF-BFS/PP composite with 90wt% SBF in SBF-BFS increases by 26.46% and 38.39%, respectively. SEM results show that the interfacial compatibility between bamboo fiber and PP matrix is poor, and the bamboo fiber is broken and pulled out. TGA results show that the thermal resistance of SBF-BFS/PP composites exhibit no obvious changes. The water resistance of SBF-BFS/PP composites show that, due to the large specific surface area of SBF, the water absorbent components in the SBF-BFS/PP composites increase with the increase of SBF content, leading to the decline of the water resistance of the SBF-BFS/PP composites.
2019, 36(11): 2568-2578.
doi: 10.13801/j.cnki.fhclxb.20190401.005
Abstract:
The jute and polypropylene fiber (PP) were formed into jute/PP composite by carding, netting and needling. Using surface dusting process, β-cyclodextrin (β-CD), β-CD and ammonium phosphate (APP) were combined and hot pressed to form a flame-retardant layer on the surface of jute/PP composite. The flame-retardant properties, mechanical properties, carbonization properties and surface microstructure of the jute/PP composites were tested by FTIR, limit oxygen index tester, horizontal combustion tester, cone calorimeter, thermogravimetric analysis tester, SEM and universal testing machine. The results show that the thermal compression film formation on the surface of jute/PP composite after β-CD and APP compounding can significantly improve the flame retardancy and thermal stability of the jute/PP composite. When the mass ratio of β-CD to APP is 1:2 and keeping the 20wt% total content of the flame retardants, the jute/PP composite becomes extinguished after 58 s combustion. The limiting oxygen index (LOI) value is 26.6%, which reaches the third fire resistance according to Japan's JISD 1201-77 standard. The heat release rate and effective combustion calorific show the lowest value and the carbon residual at 700℃ is increased by 11.68%. The mechanical properties test of the jute/PP composites show that the flexible strength increases while the tensile strength shows little change by adding flame-retardant layer on the surface of the jute/PP composites.
The jute and polypropylene fiber (PP) were formed into jute/PP composite by carding, netting and needling. Using surface dusting process, β-cyclodextrin (β-CD), β-CD and ammonium phosphate (APP) were combined and hot pressed to form a flame-retardant layer on the surface of jute/PP composite. The flame-retardant properties, mechanical properties, carbonization properties and surface microstructure of the jute/PP composites were tested by FTIR, limit oxygen index tester, horizontal combustion tester, cone calorimeter, thermogravimetric analysis tester, SEM and universal testing machine. The results show that the thermal compression film formation on the surface of jute/PP composite after β-CD and APP compounding can significantly improve the flame retardancy and thermal stability of the jute/PP composite. When the mass ratio of β-CD to APP is 1:2 and keeping the 20wt% total content of the flame retardants, the jute/PP composite becomes extinguished after 58 s combustion. The limiting oxygen index (LOI) value is 26.6%, which reaches the third fire resistance according to Japan's JISD 1201-77 standard. The heat release rate and effective combustion calorific show the lowest value and the carbon residual at 700℃ is increased by 11.68%. The mechanical properties test of the jute/PP composites show that the flexible strength increases while the tensile strength shows little change by adding flame-retardant layer on the surface of the jute/PP composites.
2019, 36(11): 2579-2586.
doi: 10.13801/j.cnki.fhclxb.20190430.001
Abstract:
In order to improve the mechanical performance and water resistance of ramie fiber/vinyl ester resin composite, a joint surface treatment method of nano SiO2-NaOH-silane coupling agent KH570 was proposed, and the chemical structure, surface morphology, crystallinity of the ramie fiber after surface treatment and the mechanical properties and water absorption behavior of the surface treatmented ramie fiber/vinyl ester resin composite were investigated. The results show that the fibroglia on the ramie fiber surfaces is dissolved by alkali liquid which loosens the fibers and improves the fiber/resin interface binding. The crystalline order index of the ramie fiber increases first and then decreases as the alkali concentration increases. The reaction between ramie and silane coupling agent increases fiber water contact angle and hydrophobicity, and the interface binding is furtherly improved. With the combined treatment of nano SiO2-NaOH-silane coupling agent KH570, the crystalline order index of the ramie fiber decreases while the static water contact angle increases, resulting in enhancement of the mechanical properties of the ramie fiber/vinyl ester resin composite. The water absorption of the ramie fiber/vinyl ester resin composite also decreases with the incorporation of nano SiO2.
In order to improve the mechanical performance and water resistance of ramie fiber/vinyl ester resin composite, a joint surface treatment method of nano SiO2-NaOH-silane coupling agent KH570 was proposed, and the chemical structure, surface morphology, crystallinity of the ramie fiber after surface treatment and the mechanical properties and water absorption behavior of the surface treatmented ramie fiber/vinyl ester resin composite were investigated. The results show that the fibroglia on the ramie fiber surfaces is dissolved by alkali liquid which loosens the fibers and improves the fiber/resin interface binding. The crystalline order index of the ramie fiber increases first and then decreases as the alkali concentration increases. The reaction between ramie and silane coupling agent increases fiber water contact angle and hydrophobicity, and the interface binding is furtherly improved. With the combined treatment of nano SiO2-NaOH-silane coupling agent KH570, the crystalline order index of the ramie fiber decreases while the static water contact angle increases, resulting in enhancement of the mechanical properties of the ramie fiber/vinyl ester resin composite. The water absorption of the ramie fiber/vinyl ester resin composite also decreases with the incorporation of nano SiO2.
2019, 36(11): 2587-2594.
doi: 10.13801/j.cnki.fhclxb.20190326.003
Abstract:
In order to investigate the effect of rice husk fiber pretreatment method (hydrothermal, microwave, alkali treatment and benzoylation treatment) on the thermal and anti-aging behavior of rice husk fiber/polyvinyl chloride (PVC) composites in simulated soil aging conditions, the TG curves of rice husk fiber/PVC composites were performed by a comprehensive thermal analyzer. The linear thermal expansion coefficient, mechanical and water absorption properties of rice husk fiber/PVC composites were characterized and the microstructure was observed by SEM. The results indicate that all the four treatment methods can improve the thermal behavior and anti-aging properties of rice husk fiber/PVC composites. The surface of the treated rice husk fiber is rougher, and the better interface of fiber and matrix lead to reducing micro-cracks. After 21 days simulated soil aging, the thermal initial decomposition temperature of benzoylated rice husk/PVC composites increases by 3.9%, compared with the untreated rice husk fiber/PVC composites. The linear thermal expansion coefficient and 24 h water absorption of benzoylated rice husk fiber/PVC composites decrease by 6.72% and 55.6%, respectively. The tensile strength and hardness increase by 103% and 119%, respectively. The benzoylated rice husk fiber/PVC composites have a good interface, and the rice husk fiber distribute uniformly. So the sequence of the four pretreatment methods is:benzoylation treatment > alkali treatment > hydrothermal treatment > microwave treatment.
In order to investigate the effect of rice husk fiber pretreatment method (hydrothermal, microwave, alkali treatment and benzoylation treatment) on the thermal and anti-aging behavior of rice husk fiber/polyvinyl chloride (PVC) composites in simulated soil aging conditions, the TG curves of rice husk fiber/PVC composites were performed by a comprehensive thermal analyzer. The linear thermal expansion coefficient, mechanical and water absorption properties of rice husk fiber/PVC composites were characterized and the microstructure was observed by SEM. The results indicate that all the four treatment methods can improve the thermal behavior and anti-aging properties of rice husk fiber/PVC composites. The surface of the treated rice husk fiber is rougher, and the better interface of fiber and matrix lead to reducing micro-cracks. After 21 days simulated soil aging, the thermal initial decomposition temperature of benzoylated rice husk/PVC composites increases by 3.9%, compared with the untreated rice husk fiber/PVC composites. The linear thermal expansion coefficient and 24 h water absorption of benzoylated rice husk fiber/PVC composites decrease by 6.72% and 55.6%, respectively. The tensile strength and hardness increase by 103% and 119%, respectively. The benzoylated rice husk fiber/PVC composites have a good interface, and the rice husk fiber distribute uniformly. So the sequence of the four pretreatment methods is:benzoylation treatment > alkali treatment > hydrothermal treatment > microwave treatment.
2019, 36(11): 2595-2602.
doi: 10.13801/j.cnki.fhclxb.20190314.002
Abstract:
Sodium montmorillonite (MMT) was modified by octadecyl trimethyl ammonium chloride (OTAC) via cation exchange to obtain organo-montmorillonite (OMMT), Al2O3 was modified by silane coupling agent KH550 to get KH-Al2O3. The polyurethane elastomer (PUE) was synthesized with 4,4'-diphenylmethane diisocyanate (MDI), polypropylene glycol (PPG) and 1,4-butanediol (BDO) as the raw materials, different mass ratio of OMMT to KH-Al2O3 with a fixed 3wt% content as the modifier, the OMMT-modified Al2O3/PUE(OMMT-Al2O3/PUE) composites were prepared by prepolymer method. The micro-morphology and mechanical properties of OMMT-Al2O3/PUE composites were measured. The results of FTIR, XRD and TEM show that the characteristic peaks of -CH2 (2 922 cm-1 and 1 469 cm-1) appear, indicating that new groups are introduced into the layers of MMT, and the interlayer spacing of OMMT is about 0.7 nm bigger than that of MMT. The characteristic peaks of -CH2 (2 924 cm-1 and 1 447 cm-1) appear, proving that KH550 is successfully grafted to the surface of Al2O3. The layer structure of OMMT can be clearly seen, and OMMT and KH-Al2O3 have good dispersion in the PUE matrix. SEM and XRD reveal that proper OMMT and KH-Al2O3 disperse evenly in the PUE matrix, and OMMT exists in the form of single layer in the OMMT-Al2O3/PUE composites. There is a certain interaction between OMMT and KH-Al2O3, and the interactions within the same molecule are reduced. The test results of mechanical properties of OMMT-Al2O3/PUE composites display that the maximum tensile strength, elongation at break and breaking tensile strength of OMMT-Al2O3/PUE composites are 21.82 MPa, 668% and 19.98 MPa, 43.8%, 29.2% and 36.8% higher than that of PUE matrix, respectively, when the mass ratio of OMMT to Al2O3 is 1:1. The mechanical properties of OMMT-Al2O3/PUE composites are significantly better than those of OMMT/PUE or Al2O3/PUE composite.
Sodium montmorillonite (MMT) was modified by octadecyl trimethyl ammonium chloride (OTAC) via cation exchange to obtain organo-montmorillonite (OMMT), Al2O3 was modified by silane coupling agent KH550 to get KH-Al2O3. The polyurethane elastomer (PUE) was synthesized with 4,4'-diphenylmethane diisocyanate (MDI), polypropylene glycol (PPG) and 1,4-butanediol (BDO) as the raw materials, different mass ratio of OMMT to KH-Al2O3 with a fixed 3wt% content as the modifier, the OMMT-modified Al2O3/PUE(OMMT-Al2O3/PUE) composites were prepared by prepolymer method. The micro-morphology and mechanical properties of OMMT-Al2O3/PUE composites were measured. The results of FTIR, XRD and TEM show that the characteristic peaks of -CH2 (2 922 cm-1 and 1 469 cm-1) appear, indicating that new groups are introduced into the layers of MMT, and the interlayer spacing of OMMT is about 0.7 nm bigger than that of MMT. The characteristic peaks of -CH2 (2 924 cm-1 and 1 447 cm-1) appear, proving that KH550 is successfully grafted to the surface of Al2O3. The layer structure of OMMT can be clearly seen, and OMMT and KH-Al2O3 have good dispersion in the PUE matrix. SEM and XRD reveal that proper OMMT and KH-Al2O3 disperse evenly in the PUE matrix, and OMMT exists in the form of single layer in the OMMT-Al2O3/PUE composites. There is a certain interaction between OMMT and KH-Al2O3, and the interactions within the same molecule are reduced. The test results of mechanical properties of OMMT-Al2O3/PUE composites display that the maximum tensile strength, elongation at break and breaking tensile strength of OMMT-Al2O3/PUE composites are 21.82 MPa, 668% and 19.98 MPa, 43.8%, 29.2% and 36.8% higher than that of PUE matrix, respectively, when the mass ratio of OMMT to Al2O3 is 1:1. The mechanical properties of OMMT-Al2O3/PUE composites are significantly better than those of OMMT/PUE or Al2O3/PUE composite.
2019, 36(11): 2603-2613.
doi: 10.13801/j.cnki.fhclxb.20190227.001
Abstract:
The unmodified and vinyl trimethoxysilane (VTS) modified nano SiO2 and micro SiO2 were used as the reinforcement phases to incorporate into polypropylene (PP) by direct dispersion (dry dispersion) or by dispersion in solution (wet dispersion), respectively. The wood flour (WF) was used as modifier to prepare WF-SiO2/PP composites. The effects of the SiO2 particle size, dispersibility and interfacial modification on the reinforcement of the WF-SiO2/PP composites were determined. Infra-red spectra show that SiO2 is grafted onto the PP matrix. Compared with the unfilled WF/PP composites, the resulting WF-SiO2/PP composites incorporated with 9% micro SiO2 or 9% nano SiO2 (mass ratio) via dry dispersion mode exhibit 21% and 18% reduction in the flexural strength, respectively. However, wet dispersion and VTS modification result in 17% and 22% increase in flexural modulus for incorporating the micro SiO2 and nano SiO2, respectively. The creep resistance is also improved obviously via wet dispersion process and VTS modification. The impact strength of the WF-SiO2/PP composites increases by 17% by filling the micro SiO2 via dry or wet dispersed modes. This study demonstrates that adding proper amount of nano or micro SiO2 can increase the impact strenth of WF-SiO2/PP composites by 15%-25% on the premise of a uniform dispersion and establishment of a well-bonded interface between the SiO2 and the matrix.
The unmodified and vinyl trimethoxysilane (VTS) modified nano SiO2 and micro SiO2 were used as the reinforcement phases to incorporate into polypropylene (PP) by direct dispersion (dry dispersion) or by dispersion in solution (wet dispersion), respectively. The wood flour (WF) was used as modifier to prepare WF-SiO2/PP composites. The effects of the SiO2 particle size, dispersibility and interfacial modification on the reinforcement of the WF-SiO2/PP composites were determined. Infra-red spectra show that SiO2 is grafted onto the PP matrix. Compared with the unfilled WF/PP composites, the resulting WF-SiO2/PP composites incorporated with 9% micro SiO2 or 9% nano SiO2 (mass ratio) via dry dispersion mode exhibit 21% and 18% reduction in the flexural strength, respectively. However, wet dispersion and VTS modification result in 17% and 22% increase in flexural modulus for incorporating the micro SiO2 and nano SiO2, respectively. The creep resistance is also improved obviously via wet dispersion process and VTS modification. The impact strength of the WF-SiO2/PP composites increases by 17% by filling the micro SiO2 via dry or wet dispersed modes. This study demonstrates that adding proper amount of nano or micro SiO2 can increase the impact strenth of WF-SiO2/PP composites by 15%-25% on the premise of a uniform dispersion and establishment of a well-bonded interface between the SiO2 and the matrix.
2019, 36(11): 2614-2627.
doi: 10.13801/j.cnki.fhclxb.20190305.004
Abstract:
The present work focuses on assessment of delamination damage in stiffened fiber reinforced polymer (FRP) composite plates through the changes in frequencies after delamination occurring. The two inverse algorithms, namely artificial neural network (ANN) and surrogate assisted optimization (SAO) were developed to predict the location and size of delamination in the stiffened FRP plates using a series of frequency shifts. The efficiency and accuracy of the frequency-based detection algorithms were validated both numerically and experimentally. The results of numerical validation show that the two proposed inverse detection algorithms can successfully identify the delamination in stiffened FRP plates with good accuracy (maximum errors are 5.04% for ANN and 5.24% for SAO, both in the prediction of delamination location). Compared to using the genetic algorithm directly, SAO can greatly enhance the prediction efficiency and maintain good accuracy. The experimental results show that the prediction accuracy of ANN is reduced greatly compared with the numerical validation due to the existence of the measurement noise in the testing, and ANN cannot give useful information of delamination in stiffened FRP plate specimens. But SAO still can obtain reasonable prediction accuracy, with maximum prediction errors of 2.05% and 9% for through-flange delamination and the embeded delamination in the base plate, while two out of four specimens have predicted the delamination to have overlapping areas with the actual delamination, of which the overlapping areas are 34% and 32.65%. In conclusion, frequency-based method using ANN and SAO as inverse algorithms is validated numerically to successfully predict delamination, but only SAO can give reasonable prediction in delamination size and location when using the measured frequencies of the stiffened plate specimens.
The present work focuses on assessment of delamination damage in stiffened fiber reinforced polymer (FRP) composite plates through the changes in frequencies after delamination occurring. The two inverse algorithms, namely artificial neural network (ANN) and surrogate assisted optimization (SAO) were developed to predict the location and size of delamination in the stiffened FRP plates using a series of frequency shifts. The efficiency and accuracy of the frequency-based detection algorithms were validated both numerically and experimentally. The results of numerical validation show that the two proposed inverse detection algorithms can successfully identify the delamination in stiffened FRP plates with good accuracy (maximum errors are 5.04% for ANN and 5.24% for SAO, both in the prediction of delamination location). Compared to using the genetic algorithm directly, SAO can greatly enhance the prediction efficiency and maintain good accuracy. The experimental results show that the prediction accuracy of ANN is reduced greatly compared with the numerical validation due to the existence of the measurement noise in the testing, and ANN cannot give useful information of delamination in stiffened FRP plate specimens. But SAO still can obtain reasonable prediction accuracy, with maximum prediction errors of 2.05% and 9% for through-flange delamination and the embeded delamination in the base plate, while two out of four specimens have predicted the delamination to have overlapping areas with the actual delamination, of which the overlapping areas are 34% and 32.65%. In conclusion, frequency-based method using ANN and SAO as inverse algorithms is validated numerically to successfully predict delamination, but only SAO can give reasonable prediction in delamination size and location when using the measured frequencies of the stiffened plate specimens.
2019, 36(11): 2628-2636.
doi: 10.13801/j.cnki.fhclxb.20190214.001
Abstract:
In order to solve the problem that there were few experimental studies on Goodman curve of composite materials in China, based on ABAQUS finite element method, Python language was used to program and calculate the fatigue strength of a new type of bullet train carbon fiber reinforced polymer (CFRP) composite equipment cabin skeleton according to Germanischer Lloyd (GL) specification Goodman curve. Through fatigue strength tests under different average stresses, the Goodman curve and the Goodman curve considering a certain safety factor were drawn and compared with the Goodman curve of GL specification. The results show that under the fatigue conditions stipulated in EN12663-1:2010[13] and reffence[14], the Goodman curve of GL specification is feasible for checking the fatigue strength of the CFRP composite equipment cabin skeleton of the new electric multiple units. The CFRP composite equipment cabin skeleton can meet the design requirements, but safety is considered. When the safety coefficient n=1.5 and n=2, the evaluation has certain risk.
In order to solve the problem that there were few experimental studies on Goodman curve of composite materials in China, based on ABAQUS finite element method, Python language was used to program and calculate the fatigue strength of a new type of bullet train carbon fiber reinforced polymer (CFRP) composite equipment cabin skeleton according to Germanischer Lloyd (GL) specification Goodman curve. Through fatigue strength tests under different average stresses, the Goodman curve and the Goodman curve considering a certain safety factor were drawn and compared with the Goodman curve of GL specification. The results show that under the fatigue conditions stipulated in EN12663-1:2010[13] and reffence[14], the Goodman curve of GL specification is feasible for checking the fatigue strength of the CFRP composite equipment cabin skeleton of the new electric multiple units. The CFRP composite equipment cabin skeleton can meet the design requirements, but safety is considered. When the safety coefficient n=1.5 and n=2, the evaluation has certain risk.
2019, 36(11): 2637-2643.
doi: 10.13801/j.cnki.fhclxb.20190401.004
Abstract:
The porous ZnO/hydroxyapatite (HA) biological composites were prepared by spark plasma sintering (SPS) technology. The effects of different nano ZnO contents on the microstructure, pore characteristics, mechanical properties, mineralization and degradation of the ZnO/HA composites were studied. The results show that the sintered ZnO/HA composites are mainly composed of HA phases and ZnO phases. With increasing of ZnO content, the porosity of the ZnO/HA composites increases slowly, the compressive strength decreases slowly, and the elastic modulus does not change much. The ZnO/HA composites have the porosity>40%, pore diameter of 50-500 μm, compressive strength>148 MPa, elastic modulus about 6.5 GPa, which can meet the requirements of bone repair materials. The mineralization and degradation experiments in simulated artificial body fluids show that a large number of osteoid apatite layers are formed on the surface of the ZnO/HA composite after soaking for 7 days. Furthermore, the apatite formation ability of the ZnO/HA composites is significantly enhanced and the degradation rate of the composites is increased with increasing of ZnO content.
The porous ZnO/hydroxyapatite (HA) biological composites were prepared by spark plasma sintering (SPS) technology. The effects of different nano ZnO contents on the microstructure, pore characteristics, mechanical properties, mineralization and degradation of the ZnO/HA composites were studied. The results show that the sintered ZnO/HA composites are mainly composed of HA phases and ZnO phases. With increasing of ZnO content, the porosity of the ZnO/HA composites increases slowly, the compressive strength decreases slowly, and the elastic modulus does not change much. The ZnO/HA composites have the porosity>40%, pore diameter of 50-500 μm, compressive strength>148 MPa, elastic modulus about 6.5 GPa, which can meet the requirements of bone repair materials. The mineralization and degradation experiments in simulated artificial body fluids show that a large number of osteoid apatite layers are formed on the surface of the ZnO/HA composite after soaking for 7 days. Furthermore, the apatite formation ability of the ZnO/HA composites is significantly enhanced and the degradation rate of the composites is increased with increasing of ZnO content.
2019, 36(11): 2644-2650.
doi: 10.13801/j.cnki.fhclxb.20190122.001
Abstract:
The silane coupling agent KH550 and polyhedral oligomeric silsesquioxane (POSS) functionalized nano BN (nBN)/methyl vinyl silicone rubber (POSS-g-nBN/MVSR) thermally conductive composites were fabricated via kneading followed by hot compression method. The thermally conductive coefficient (λ), dielectric constant (ε) and dielectric loss tangent (tanδ) values of the nBN/MVSR composites are all increased with increasing addition of nBN. For a given nBN loading, the surface functionalization of nBN can further increase λ and decrease ε and tanδ of the nBN/MVSR composites. The maximum λ value of the POSS-g-nBN/MVSR composites improves to 0.92 W/(mK) with 30vol% POSS-g-nBN, which is about 5 times of the pure MVSR matrix (0.18 W(mK)-1) and also higher than that of nBN/MVSR composites with 30vol% nBN (0.77 W(mK)-1). In comparison to that of pristine nBN fillers, POSS-g-nBN fillers are easier to form thermally conductive channels in MVSR matrix and possess relatively lower interfacial thermal resistance with MVSR matrix. The corresponding ε and tanδ of the POSS-g-nBN/MVSR composites are 3.39 and 0.0049, respectively, slightly lower than that of nBN/MVSR composites with 30vol% nBN (ε of 3.43 and tanδ of 0.0057).
The silane coupling agent KH550 and polyhedral oligomeric silsesquioxane (POSS) functionalized nano BN (nBN)/methyl vinyl silicone rubber (POSS-g-nBN/MVSR) thermally conductive composites were fabricated via kneading followed by hot compression method. The thermally conductive coefficient (λ), dielectric constant (ε) and dielectric loss tangent (tanδ) values of the nBN/MVSR composites are all increased with increasing addition of nBN. For a given nBN loading, the surface functionalization of nBN can further increase λ and decrease ε and tanδ of the nBN/MVSR composites. The maximum λ value of the POSS-g-nBN/MVSR composites improves to 0.92 W/(mK) with 30vol% POSS-g-nBN, which is about 5 times of the pure MVSR matrix (0.18 W(mK)-1) and also higher than that of nBN/MVSR composites with 30vol% nBN (0.77 W(mK)-1). In comparison to that of pristine nBN fillers, POSS-g-nBN fillers are easier to form thermally conductive channels in MVSR matrix and possess relatively lower interfacial thermal resistance with MVSR matrix. The corresponding ε and tanδ of the POSS-g-nBN/MVSR composites are 3.39 and 0.0049, respectively, slightly lower than that of nBN/MVSR composites with 30vol% nBN (ε of 3.43 and tanδ of 0.0057).
2019, 36(11): 2651-2664.
doi: 10.13801/j.cnki.fhclxb.20181224.002
Abstract:
In order to improve the impedance matching of traditional magnetic absorbing materials and improve the electromagnetic wave absorption performance, the ternary composites, composed of magnetic material Fe3O4, a wave-transparent material lithium aluminum silicate glass-ceramic (LAS) and reduced graphene oxide (RGO), were prepared by three-step method. The structure, morphology and composition of the Fe3O4@LAS/RGO composites were characterized by various test methods, and the electromagnetic parameters and microwave absorbing properties were also analyzed. The effects of the addition amount of graphite oxide (GO) on the formation and microwave absorbing properties of the Fe3O4@LAS/RGO composites were investigated. As the amount of GO increases, the distribution of Fe3O4@LAS nanospheres becomes sparse, and the degree of stacking of RGO increases. When the mass fraction of GO is 40wt% (the molar ratio of Fe3O4/LAS is 1:0.2), the Fe3O4@LAS/RGO composite has the best microwave absorbing performance. The reflection loss reaches -65 dB at 12.4 GHz with a thickness of 2.1 mm and the absorption bandwidth with the reflection loss values less than -10 dB (more than 90% of electromagnetic waves are absorbed by materials) is up to 4 GHz at the corresponding thickness. The LAS, having wave-transparent properties, can introduce a multiple transmission-absorption mechanism into the Fe3O4@LAS/RGO composites.
In order to improve the impedance matching of traditional magnetic absorbing materials and improve the electromagnetic wave absorption performance, the ternary composites, composed of magnetic material Fe3O4, a wave-transparent material lithium aluminum silicate glass-ceramic (LAS) and reduced graphene oxide (RGO), were prepared by three-step method. The structure, morphology and composition of the Fe3O4@LAS/RGO composites were characterized by various test methods, and the electromagnetic parameters and microwave absorbing properties were also analyzed. The effects of the addition amount of graphite oxide (GO) on the formation and microwave absorbing properties of the Fe3O4@LAS/RGO composites were investigated. As the amount of GO increases, the distribution of Fe3O4@LAS nanospheres becomes sparse, and the degree of stacking of RGO increases. When the mass fraction of GO is 40wt% (the molar ratio of Fe3O4/LAS is 1:0.2), the Fe3O4@LAS/RGO composite has the best microwave absorbing performance. The reflection loss reaches -65 dB at 12.4 GHz with a thickness of 2.1 mm and the absorption bandwidth with the reflection loss values less than -10 dB (more than 90% of electromagnetic waves are absorbed by materials) is up to 4 GHz at the corresponding thickness. The LAS, having wave-transparent properties, can introduce a multiple transmission-absorption mechanism into the Fe3O4@LAS/RGO composites.
2019, 36(11): 2665-2673.
doi: 10.13801/j.cnki.fhclxb.20181214.001
Abstract:
The TiO2/river sediment (RS) was used as the raw materials to synthesize the visible-light catalyst by sol-gel method, in which the RS served as carrier and tetraisopropyl titanate (TTIP) functioned as precursors. The catalytic activity, recyclability and stability of the TiO2/RS composite catalyst under visible light were investigated in depth. The crystal form, morphology, surface morphology and pore structure of TiO2/RS composites were characterized by XRD, SEM, XPS and BET. By catalyst characterization, it is found that the porous structure of the TiO2/RS composite is more obvious than the pure TiO2, and its specific surface area can be increased to 98.43 m2/g. The catalytic ability of TiO2/RS composite with the mass ratio of river sediment to TiO2 of 0.5 is tested in the visible light assisted degradation systems by using methyl orange as the model pollutant. The results show that the degradation efficiency of methyl orange can reach 48.8% after 4 h and the dye removal can remain over 45% after 6 cycles of catalyst recycling.
The TiO2/river sediment (RS) was used as the raw materials to synthesize the visible-light catalyst by sol-gel method, in which the RS served as carrier and tetraisopropyl titanate (TTIP) functioned as precursors. The catalytic activity, recyclability and stability of the TiO2/RS composite catalyst under visible light were investigated in depth. The crystal form, morphology, surface morphology and pore structure of TiO2/RS composites were characterized by XRD, SEM, XPS and BET. By catalyst characterization, it is found that the porous structure of the TiO2/RS composite is more obvious than the pure TiO2, and its specific surface area can be increased to 98.43 m2/g. The catalytic ability of TiO2/RS composite with the mass ratio of river sediment to TiO2 of 0.5 is tested in the visible light assisted degradation systems by using methyl orange as the model pollutant. The results show that the degradation efficiency of methyl orange can reach 48.8% after 4 h and the dye removal can remain over 45% after 6 cycles of catalyst recycling.
2019, 36(11): 2674-2682.
doi: 10.13801/j.cnki.fhclxb.20190220.001
Abstract:
The 2D face-to-face oriented hetero-layered composites reduced graphene oxide-graphite phase carbon nitride(RGO-g-C3N4) was fabricated by electrostatic self-assembly of RGO and g-C3N4 nanosheet. The g-C3N4 nanosheet and RGO was obtained by stripping the bulk multi-layer graphite carbon nitride (B-g-C3N4) and modified graphene oxide (GO) with polydiallyldimethylammonium chloride (PDDA), respectively. Zeta potential study shows that the process of self-assembly is influenced obviously by the Zeta potentials of RGO and g-C3N4 and the process is mainly controlled by charge neutralization. The characterization results of Raman spectroscopy and XPS indicate that the 2D layered RGO-g-C3N4 composites behave the common structural features of both g-C3N4 and RGO. The results of SEM and TEM also demonstrate that the layers of RGO and g-C3N4 are combined face-to-face in vertical direction and the RGO-g-C3N4 composites remain layer structure but with thickness increase obviously. The thermal conductivity of RGO-g-C3N4 composites is higher than that of simple mixture RGO+g-C3N4 with the same mass fraction of components. And the thermal conductivity of the RGO-g-C3N4 composites increases when RGO increasing. When the RGO content is 24.4 wt%, the thermal conductivity of the RGO-g-C3N4 composites is 4.2 W/(mK), which is 1.4 times of the thermal conductivity of RGO+g-C3N4 composites mixed simply with the same mass fraction of components.
The 2D face-to-face oriented hetero-layered composites reduced graphene oxide-graphite phase carbon nitride(RGO-g-C3N4) was fabricated by electrostatic self-assembly of RGO and g-C3N4 nanosheet. The g-C3N4 nanosheet and RGO was obtained by stripping the bulk multi-layer graphite carbon nitride (B-g-C3N4) and modified graphene oxide (GO) with polydiallyldimethylammonium chloride (PDDA), respectively. Zeta potential study shows that the process of self-assembly is influenced obviously by the Zeta potentials of RGO and g-C3N4 and the process is mainly controlled by charge neutralization. The characterization results of Raman spectroscopy and XPS indicate that the 2D layered RGO-g-C3N4 composites behave the common structural features of both g-C3N4 and RGO. The results of SEM and TEM also demonstrate that the layers of RGO and g-C3N4 are combined face-to-face in vertical direction and the RGO-g-C3N4 composites remain layer structure but with thickness increase obviously. The thermal conductivity of RGO-g-C3N4 composites is higher than that of simple mixture RGO+g-C3N4 with the same mass fraction of components. And the thermal conductivity of the RGO-g-C3N4 composites increases when RGO increasing. When the RGO content is 24.4 wt%, the thermal conductivity of the RGO-g-C3N4 composites is 4.2 W/(mK), which is 1.4 times of the thermal conductivity of RGO+g-C3N4 composites mixed simply with the same mass fraction of components.
2019, 36(11): 2683-2691.
doi: 10.13801/j.cnki.fhclxb.20190320.001
Abstract:
The expanded graphene was stripped by physical and mechanical stripping method, and the nano graphene sheets (GE) with thickness of 10 nm and horizontal size of 10-20 μm were obtained, and the GE/natural rubber (NR) concentrated masterbatch with mass fraction of 20wt% was further prepared. The hydrophobic SiO2 was obtained by modifying the precipitated SiO2 with the silane coupling agent KH580. The GE-SiO2/NR composites which contain 0, 0.2wt%, 0.5wt%, 1.0wt% and 2.0wt% GE were prepared by mechanical blending. By testing the conductive and thermal conductivity of the GE-SiO2/NR composites, it is found that its thermal and electrical conductivity gradually improve with the increase of GE content. When the GE content is 2.0wt%, the thermal conductivity in pane increases by 38.1%, the thermal conductivity through pane increases by 36.21% and the electrical conductivity increases by 36.07%. The higher the GE content, the greater the 100% and 300% tensile stress of the GE-SiO2/NR composites, but the change of tensile strength, tearing strength and breaking elongation are not obvious. With the increase of GE content, the network effect of filler and Payane effect are weakened, and the glass temperature gradually increases. According to the SEM analysis, the modified SiO2 is well dispersed in the NR matrix without agglomeration. When the GE content is 2.0wt%, the lamellar structure of GE is obviously observed.
The expanded graphene was stripped by physical and mechanical stripping method, and the nano graphene sheets (GE) with thickness of 10 nm and horizontal size of 10-20 μm were obtained, and the GE/natural rubber (NR) concentrated masterbatch with mass fraction of 20wt% was further prepared. The hydrophobic SiO2 was obtained by modifying the precipitated SiO2 with the silane coupling agent KH580. The GE-SiO2/NR composites which contain 0, 0.2wt%, 0.5wt%, 1.0wt% and 2.0wt% GE were prepared by mechanical blending. By testing the conductive and thermal conductivity of the GE-SiO2/NR composites, it is found that its thermal and electrical conductivity gradually improve with the increase of GE content. When the GE content is 2.0wt%, the thermal conductivity in pane increases by 38.1%, the thermal conductivity through pane increases by 36.21% and the electrical conductivity increases by 36.07%. The higher the GE content, the greater the 100% and 300% tensile stress of the GE-SiO2/NR composites, but the change of tensile strength, tearing strength and breaking elongation are not obvious. With the increase of GE content, the network effect of filler and Payane effect are weakened, and the glass temperature gradually increases. According to the SEM analysis, the modified SiO2 is well dispersed in the NR matrix without agglomeration. When the GE content is 2.0wt%, the lamellar structure of GE is obviously observed.
2019, 36(11): 2692-2698.
doi: 10.13801/j.cnki.fhclxb.20190122.003
Abstract:
The graphene oxide(GO)-SiO2/natural rubber composite was prepared by a self-developed spray sputtering drying method. Based on the principle of sputter blasting of the liquid column at high pressure against the metal wall with high temperature, achieved the secondary dispersion of droplets and the instantaneous removal of moisture and keeping the high dispersion state of GO-SiO2 fillers in the natural latex. The effect of the spray pressure on the dispersion of GO-SiO2 fillers and on GO-SiO2/natural rubber composite by spray sputtering drying method was investigated. The experimental results show that higher or lower pressure is not conducive to the preparation of high-performance masterbatch. When the spray pressure is 0.8 MPa, the dispersion effect of GO-SiO2 filler in the rubber is the best, and GO-SiO2/natural rubber composite has the best comprehensive properties. The tensile strength is 31.2 MPa, the tear strength is 89.01 kNm-1, the elongation at break is 670.90%, and the loss factor is lower at about 60℃.
The graphene oxide(GO)-SiO2/natural rubber composite was prepared by a self-developed spray sputtering drying method. Based on the principle of sputter blasting of the liquid column at high pressure against the metal wall with high temperature, achieved the secondary dispersion of droplets and the instantaneous removal of moisture and keeping the high dispersion state of GO-SiO2 fillers in the natural latex. The effect of the spray pressure on the dispersion of GO-SiO2 fillers and on GO-SiO2/natural rubber composite by spray sputtering drying method was investigated. The experimental results show that higher or lower pressure is not conducive to the preparation of high-performance masterbatch. When the spray pressure is 0.8 MPa, the dispersion effect of GO-SiO2 filler in the rubber is the best, and GO-SiO2/natural rubber composite has the best comprehensive properties. The tensile strength is 31.2 MPa, the tear strength is 89.01 kNm-1, the elongation at break is 670.90%, and the loss factor is lower at about 60℃.
2019, 36(11): 2699-2709.
doi: 10.13801/j.cnki.fhclxb.20190326.001
Abstract:
The monodisperse and precipitated silica (SiO2) were modified by coupling agent Si747 in liquid phase and the SiO2/natural rubber (NR) composites were prepared by latex compounding technology. The structure and properties of Si747-modified SiO2/NR composites were characterized by rubber process analyzer, DMA and SEM. The results show that in terms of the vulcanization characteristics, compared with the unmodified SiO2, the scorch time and the positive vulcanization time of the composites obtained by using coupling agent Si747 modified SiO2 and NR are shortened, which promoted the vulcanization process of rubber. The scorch time and the positive vulcanization time of the monodisperse SiO2/NR vulcanizates were longer than that of the precipitated SiO2/NR vulcanizates before and after SiO2 modification; Considering the physical and mechanical properties, compared with unmodified SiO2/NR vulcanizate, the tensile strength of the modified monodisperse SiO2/NR vulcanizate is increased by 17.4%. The resilience and wear resistance are improved by 9.5% and 32.6%, respectively. The heat-build up is reduced by 24.3%. In terms of dynamic viscoelasticity, the modified monodisperse SiO2/NR vulcanizate has the lower Payne effect, the better dispersibility of the filler and the weaker filler network compared with the modified precipitated SiO2/NR vulcanizate. In terms of dynamic mechanical properties, the performance in wet-slip resistance of modified monodisperse SiO2/NR vulcanizate is slightly lower than that of the modified precipitated SiO2/NR vulcanizate, but the rolling resistance is much better than the latter and saves more energy.
The monodisperse and precipitated silica (SiO2) were modified by coupling agent Si747 in liquid phase and the SiO2/natural rubber (NR) composites were prepared by latex compounding technology. The structure and properties of Si747-modified SiO2/NR composites were characterized by rubber process analyzer, DMA and SEM. The results show that in terms of the vulcanization characteristics, compared with the unmodified SiO2, the scorch time and the positive vulcanization time of the composites obtained by using coupling agent Si747 modified SiO2 and NR are shortened, which promoted the vulcanization process of rubber. The scorch time and the positive vulcanization time of the monodisperse SiO2/NR vulcanizates were longer than that of the precipitated SiO2/NR vulcanizates before and after SiO2 modification; Considering the physical and mechanical properties, compared with unmodified SiO2/NR vulcanizate, the tensile strength of the modified monodisperse SiO2/NR vulcanizate is increased by 17.4%. The resilience and wear resistance are improved by 9.5% and 32.6%, respectively. The heat-build up is reduced by 24.3%. In terms of dynamic viscoelasticity, the modified monodisperse SiO2/NR vulcanizate has the lower Payne effect, the better dispersibility of the filler and the weaker filler network compared with the modified precipitated SiO2/NR vulcanizate. In terms of dynamic mechanical properties, the performance in wet-slip resistance of modified monodisperse SiO2/NR vulcanizate is slightly lower than that of the modified precipitated SiO2/NR vulcanizate, but the rolling resistance is much better than the latter and saves more energy.
2019, 36(11): 2710-2717.
doi: 10.13801/j.cnki.fhclxb.20190318.003
Abstract:
With Na-montmorillonite (Na-M) as the research object, cetyl trimethyl ammonium bromide-silane coupling agent KH550 (CTAB-SCA) modified Na-M was prepared by using CTAB and SCA as the modifier and deionized water and absolute ethyl alcohol as the solvent. The influences of the mass ratio of CTAB and deionized water, the mass ratio of SCA to absolute ethyl alcohol and the mass ratio of carbon black to CTAB-SCA modified Na-M on the mechanical performance and flame retardant performance of CTAB-SCA modified Na-M/rubber composites were explored. The microscopic morphology, mineral composition and composition structure were characterized by SEM, XRD and FTIR, respectively. The results show that the prepared CTAB-SCA modified Na-M/rubber composite has good mechanical performance and the flame retardant performance (tensile strength is 18.9 MPa, tear strength is 42.9 kNm-1 and limit oxygen index is 31.51%) when the mass ratio of carbon black to CTAB-SCA modified Na-M is 20:30, the mass ratio of CTAB to deionized water is 13.5:1050 and the mass ratio of SCA to absolute ethyl alcohol is 0.30:15. The mixture of CTAB-deionized water can reduce the polarity between slice layers of CTAB-SCA modified Na-M to improve lipophilicity. The mixture of SCA-absolute ethyl alcohol with surface hydroxyl of CTAB-SCA modified Na-M in chemistry improves dispersion. The carbon black is the main reinforcing material, CTAB-SCA modified Na-M is main flame retardant and auxiliary reinforcing composites in CTAB-SCA modified Na-M/rubber composites.
With Na-montmorillonite (Na-M) as the research object, cetyl trimethyl ammonium bromide-silane coupling agent KH550 (CTAB-SCA) modified Na-M was prepared by using CTAB and SCA as the modifier and deionized water and absolute ethyl alcohol as the solvent. The influences of the mass ratio of CTAB and deionized water, the mass ratio of SCA to absolute ethyl alcohol and the mass ratio of carbon black to CTAB-SCA modified Na-M on the mechanical performance and flame retardant performance of CTAB-SCA modified Na-M/rubber composites were explored. The microscopic morphology, mineral composition and composition structure were characterized by SEM, XRD and FTIR, respectively. The results show that the prepared CTAB-SCA modified Na-M/rubber composite has good mechanical performance and the flame retardant performance (tensile strength is 18.9 MPa, tear strength is 42.9 kNm-1 and limit oxygen index is 31.51%) when the mass ratio of carbon black to CTAB-SCA modified Na-M is 20:30, the mass ratio of CTAB to deionized water is 13.5:1050 and the mass ratio of SCA to absolute ethyl alcohol is 0.30:15. The mixture of CTAB-deionized water can reduce the polarity between slice layers of CTAB-SCA modified Na-M to improve lipophilicity. The mixture of SCA-absolute ethyl alcohol with surface hydroxyl of CTAB-SCA modified Na-M in chemistry improves dispersion. The carbon black is the main reinforcing material, CTAB-SCA modified Na-M is main flame retardant and auxiliary reinforcing composites in CTAB-SCA modified Na-M/rubber composites.
2019, 36(11): 2718-2725.
doi: 10.13801/j.cnki.fhclxb.20190104.002
Abstract:
The basalt fiber (BF) was modified with oxalic acid and FeSO47H2O as the raw materials by liquid phase deposition method. The basalt fibers before and after being modified were characterized by SEM, EDS, XPS, contact angel analyzer and Zeta potential analyzer to observe the micro-morphology, elemental composition, hydrophilic and electronegativity. The toxicity of basalt fiber was evaluated by the growth curves of bacillus subtilis in different environment and the impacts of basalt fiber modified with ferric oxalate (MBF) on microorganism adhesion were evaluated by pure adhesion and activated sludge immobilization tests. The results show that the hydrophilic and electronegativity are significantly improved, the water contact angle of MBF decreases from 89.71° to 56.74° and the Zeta potential of MBF increases from -18.53 mV to -5.03 mV by comparison with BF. The MBF do not inhibit bacteria growth and possess no bacterial toxicity. The amount of sludge immobilized onto MBF is 27.91 gm-2 after 12 h, indicating that ferric oxalate could promote more biomass adhering on MBF surface, thus being favor to the improvement of the effect of waste water treatment.
The basalt fiber (BF) was modified with oxalic acid and FeSO47H2O as the raw materials by liquid phase deposition method. The basalt fibers before and after being modified were characterized by SEM, EDS, XPS, contact angel analyzer and Zeta potential analyzer to observe the micro-morphology, elemental composition, hydrophilic and electronegativity. The toxicity of basalt fiber was evaluated by the growth curves of bacillus subtilis in different environment and the impacts of basalt fiber modified with ferric oxalate (MBF) on microorganism adhesion were evaluated by pure adhesion and activated sludge immobilization tests. The results show that the hydrophilic and electronegativity are significantly improved, the water contact angle of MBF decreases from 89.71° to 56.74° and the Zeta potential of MBF increases from -18.53 mV to -5.03 mV by comparison with BF. The MBF do not inhibit bacteria growth and possess no bacterial toxicity. The amount of sludge immobilized onto MBF is 27.91 gm-2 after 12 h, indicating that ferric oxalate could promote more biomass adhering on MBF surface, thus being favor to the improvement of the effect of waste water treatment.
2019, 36(11): 2726-2733.
doi: 10.13801/j.cnki.fhclxb.20190318.002
Abstract:
The aligned carbon fiber reinforced cement mortar was prepared by magnetic field induced orientation technology. The carbon fiber orientations, compression strengths and splitting tensile strengths of cement mortars with different water-cement ratios, ages and fiber contents were measured. The effects of carbon fiber content and orientation on the mechanical properties of prepared cement mortars were studied. The results show that the water-cement ratio and fiber content have a significant effect on the orientation of carbon fiber. Besides, compared with the ordinary carbon fiber reinforced cement mortar, the aligned carbon fiber reinforced cement mortar has a significant increase in the splitting tensile strength, while exhibits no obvious change in the compressive strength. With the same water-cement ratio, the fiber orientation and fiber content are the main factors affecting the splitting tensile strength of aligned carbon fiber reinforced cement mortar. Especially, the optimum content of carbon fiber in the aligned carbon fiber reinforced cement is 0.50% of the cement mass, which has the highest increasing ratio of splitting tensile strength.
The aligned carbon fiber reinforced cement mortar was prepared by magnetic field induced orientation technology. The carbon fiber orientations, compression strengths and splitting tensile strengths of cement mortars with different water-cement ratios, ages and fiber contents were measured. The effects of carbon fiber content and orientation on the mechanical properties of prepared cement mortars were studied. The results show that the water-cement ratio and fiber content have a significant effect on the orientation of carbon fiber. Besides, compared with the ordinary carbon fiber reinforced cement mortar, the aligned carbon fiber reinforced cement mortar has a significant increase in the splitting tensile strength, while exhibits no obvious change in the compressive strength. With the same water-cement ratio, the fiber orientation and fiber content are the main factors affecting the splitting tensile strength of aligned carbon fiber reinforced cement mortar. Especially, the optimum content of carbon fiber in the aligned carbon fiber reinforced cement is 0.50% of the cement mass, which has the highest increasing ratio of splitting tensile strength.
