2019 Vol. 36, No. 3
2019, 36(3): 545-554.
doi: 10.13801/j.cnki.fhclxb.20180705.001
Abstract:
A novel dicyanide-containing silane coupling agent (DCA) was synthesized and characterized with FTIR, 1H-NMR and 13C-NMR. After modified by the coupling agent DCA(2.0wt%), the interlaminar shear strength (ILSS) and flexural strength of the quartz fiber/poly(silicon-containing arylacetylene) (QF/PSA) composites increase by 63.3% and 28.1% at room temperature respectively. The retention of ILSS and flexural strength of QF/PSA are 83.0% and 81.9% respectively at 250℃, the retention of ILSS and flexural strength are 54.7% and 60.0% respectively at 500℃. The decomposition temperature of 5% loss (Td5) of the cured DCA is 357.8℃, and its residue rate is up to 55.7% at 900℃. According to DSC analysis, the dicyanide groups cure at about 229℃, and the alkenyl groups copolymerized with PSA at 245℃.The strong interfacial layer form between QF and PSA. XPS analysis shows that DCA could form chemical bonds as the bridges between the matrix and fibers. Confirmed by SEM, the rupture mode of QF/PSA composites modified by DCA on the interface is obviously ductile fracture. DCA can apparently modify the interface of QF/PSA composites and improve its mechanical properties.
A novel dicyanide-containing silane coupling agent (DCA) was synthesized and characterized with FTIR, 1H-NMR and 13C-NMR. After modified by the coupling agent DCA(2.0wt%), the interlaminar shear strength (ILSS) and flexural strength of the quartz fiber/poly(silicon-containing arylacetylene) (QF/PSA) composites increase by 63.3% and 28.1% at room temperature respectively. The retention of ILSS and flexural strength of QF/PSA are 83.0% and 81.9% respectively at 250℃, the retention of ILSS and flexural strength are 54.7% and 60.0% respectively at 500℃. The decomposition temperature of 5% loss (Td5) of the cured DCA is 357.8℃, and its residue rate is up to 55.7% at 900℃. According to DSC analysis, the dicyanide groups cure at about 229℃, and the alkenyl groups copolymerized with PSA at 245℃.The strong interfacial layer form between QF and PSA. XPS analysis shows that DCA could form chemical bonds as the bridges between the matrix and fibers. Confirmed by SEM, the rupture mode of QF/PSA composites modified by DCA on the interface is obviously ductile fracture. DCA can apparently modify the interface of QF/PSA composites and improve its mechanical properties.
2019, 36(3): 555-562.
doi: 10.13801/j.cnki.fhclxb.20180704.003
Abstract:
With nylon 6 (PA6) as the matrix and carbon fiber (CF), expanded graphite (EG) as the thermal conductive filler, EG/PA6, CF/PA6 and CF-EG/PA6 thermal conductive composites were prepared by melt-mixing. Fixed the filling content of 40wt%, the effects of different ratios of CF to EG on the contact mode between CF and EG, and the thermal conductivity and mechanical properties of CF-EG/PA6 composites were studied. The results indicate that the addition of EG is beneficial to increase of the thermal conductivity of CF-EG/PA6 composites compared to single CF filling; When CF:EG mass ratio is 25:15, the thermal conductivity of CF-EG/PA6 composite reaches 2.554 W/(m·K), which is 7 times higher than that of PA6, the tensile strength is increased by 125.34%, the flexual strength is increased by 119.8%, and the heat resistance demonstrates excellent. The SEM results show that fibrous CF and worm-like EG can form a 3D network structure with "Terms contact" under the appropriate filling ratio. The 3D network structure not only significantly increases the thermal conductivity of CF-EG/PA6 composite, but also significantly improves the mechanical and thermal properties of the composite. It provides a new idea for the development of filled thermally conductive polymer materials.
With nylon 6 (PA6) as the matrix and carbon fiber (CF), expanded graphite (EG) as the thermal conductive filler, EG/PA6, CF/PA6 and CF-EG/PA6 thermal conductive composites were prepared by melt-mixing. Fixed the filling content of 40wt%, the effects of different ratios of CF to EG on the contact mode between CF and EG, and the thermal conductivity and mechanical properties of CF-EG/PA6 composites were studied. The results indicate that the addition of EG is beneficial to increase of the thermal conductivity of CF-EG/PA6 composites compared to single CF filling; When CF:EG mass ratio is 25:15, the thermal conductivity of CF-EG/PA6 composite reaches 2.554 W/(m·K), which is 7 times higher than that of PA6, the tensile strength is increased by 125.34%, the flexual strength is increased by 119.8%, and the heat resistance demonstrates excellent. The SEM results show that fibrous CF and worm-like EG can form a 3D network structure with "Terms contact" under the appropriate filling ratio. The 3D network structure not only significantly increases the thermal conductivity of CF-EG/PA6 composite, but also significantly improves the mechanical and thermal properties of the composite. It provides a new idea for the development of filled thermally conductive polymer materials.
2019, 36(3): 563-571.
doi: 10.13801/j.cnki.fhclxb.20180621.001
Abstract:
The Compound modifications of poly(lactic acid)(PLA) were conducted by using nano SiO2 or one organic matter as the electrets (O-electret), and using epoxy soybean oil (ESO) and poly(ethylene) (PEG) as the combined plasticizers, respectively. Then the biodegradable electret-plasticizer/PLA meltblown nonwoven composites were manufactured on a commercial meltblown production line. The melt flowability of modified PLA chips was tested by using a torque rheometer and a melt flow index (MFI) instrument. It is found that addition of ESO and PEG improves the MFI to 110 g/10 min. The mechanical properties of meltblown nonwoven composite were tested by DMA. The relevant results indicate that the strength and plasticity of meltblown nonwoven composites can be remarkably enhanced after being modified by plasticizers. Filter media testing platform was used to evaluate the filtration performance of electret-plasticizer/PLA meltblown nonwoven composites. It is found that introduction of electret could improve the PM2.5 filtration efficiency of that to 86% or more. SEM observations were eventually employed to study the micromorphology of the nonwoven composites, the result shows that the ratio of fine fibers within the PLA meltblown nonwoven has been increased notably after electret modification, and with the help of plasticizers such microscale fibers became relatively longer and finer, hence the interlacement of these fibers turned more complex.
The Compound modifications of poly(lactic acid)(PLA) were conducted by using nano SiO2 or one organic matter as the electrets (O-electret), and using epoxy soybean oil (ESO) and poly(ethylene) (PEG) as the combined plasticizers, respectively. Then the biodegradable electret-plasticizer/PLA meltblown nonwoven composites were manufactured on a commercial meltblown production line. The melt flowability of modified PLA chips was tested by using a torque rheometer and a melt flow index (MFI) instrument. It is found that addition of ESO and PEG improves the MFI to 110 g/10 min. The mechanical properties of meltblown nonwoven composite were tested by DMA. The relevant results indicate that the strength and plasticity of meltblown nonwoven composites can be remarkably enhanced after being modified by plasticizers. Filter media testing platform was used to evaluate the filtration performance of electret-plasticizer/PLA meltblown nonwoven composites. It is found that introduction of electret could improve the PM2.5 filtration efficiency of that to 86% or more. SEM observations were eventually employed to study the micromorphology of the nonwoven composites, the result shows that the ratio of fine fibers within the PLA meltblown nonwoven has been increased notably after electret modification, and with the help of plasticizers such microscale fibers became relatively longer and finer, hence the interlacement of these fibers turned more complex.
2019, 36(3): 572-577.
doi: 10.13801/j.cnki.fhclxb.20180704.002
Abstract:
The polyethylene terephthalate (PET) nanofiber membranes with different spinning times were prepared by electrospinning technique. The PET nanofiber membrane, hot melt membrane and polyester needle felt were heat-treated and composited to prepare the sandwich structure of PET nanofiber membrane/polyester needle felt composite filters. The morphology of PET nanofiber membranes and heat treatment conditions of nanofiber membranes were analyzed by SEM and TGA. The air permeability and filtration performance of the PET nanofiber membrane/polyester needle felt composite filters with different spinning times were studied. The results indicate that the average diameter of the fibers of PET nanofiber membrane is 514.95 nm under the conditions of 18% spinning solution concentration, 15 kV spinning voltage, 21 cm receiving distance, 13℃ ambient temperature and 20% ambient humidity. 115℃ is the suitable composite temperature of PET nanofiber membrane/polyester needle felt composite filters. With the increase of spinning time, the density and filtration efficiency of PET nanofiber membrane/polyester needle felt composite filters to particles increase, and air permeability decrease. With 3.86 g/m2 density, the filtration performance of PET nanofiber membrane/polyester needle felt composite filters is the best, and the quality factor QF is obviously better than conventional polyester needle felt. The filtration efficiency of particles below 1 μm is higher than 93% and the efficiency is improved by 58%. The PET nanofiber membrane/polyester needle felt composite filters show excellent filtration performance.
The polyethylene terephthalate (PET) nanofiber membranes with different spinning times were prepared by electrospinning technique. The PET nanofiber membrane, hot melt membrane and polyester needle felt were heat-treated and composited to prepare the sandwich structure of PET nanofiber membrane/polyester needle felt composite filters. The morphology of PET nanofiber membranes and heat treatment conditions of nanofiber membranes were analyzed by SEM and TGA. The air permeability and filtration performance of the PET nanofiber membrane/polyester needle felt composite filters with different spinning times were studied. The results indicate that the average diameter of the fibers of PET nanofiber membrane is 514.95 nm under the conditions of 18% spinning solution concentration, 15 kV spinning voltage, 21 cm receiving distance, 13℃ ambient temperature and 20% ambient humidity. 115℃ is the suitable composite temperature of PET nanofiber membrane/polyester needle felt composite filters. With the increase of spinning time, the density and filtration efficiency of PET nanofiber membrane/polyester needle felt composite filters to particles increase, and air permeability decrease. With 3.86 g/m2 density, the filtration performance of PET nanofiber membrane/polyester needle felt composite filters is the best, and the quality factor QF is obviously better than conventional polyester needle felt. The filtration efficiency of particles below 1 μm is higher than 93% and the efficiency is improved by 58%. The PET nanofiber membrane/polyester needle felt composite filters show excellent filtration performance.
2019, 36(3): 578-583.
doi: 10.13801/j.cnki.fhclxb.20180613.002
Abstract:
Styrene butyl acrylate copolymer (SBA) was prepared by emulsion polymerization. The reduced graphene oxide-SBA/polymethyl methacrylate (rGO-SBA/PMMA) composites were fabricated through melt blending method. The structure of the rGO-SBA/PMMA composite was characterized by FTIR, TGA and dynamic mechanical analysis, and the dielectric properties of the composites were tested. The results show that the addition of rGO can increase the glass transition temperature of SBA. At the same time, it can enhance the thermal stability of rGO-SBA composites. Moreover, the addition of rGO significantly increases the dielectric constant of the rGO-SBA composites. rGO-SBA composite possesses the property of high dielectric. For rGO-SBA/PMMA composites, when the SBA content is 13wt% and the rGO content is 0.52wt%, the dielectric constant can approach to 8.79 and the dielectric loss is as low as 0.37 at 1 000 Hz, which further shows that the rGO-SBA/PMMA composites have the characteristics of high dielectric constant and low dielectric loss.
Styrene butyl acrylate copolymer (SBA) was prepared by emulsion polymerization. The reduced graphene oxide-SBA/polymethyl methacrylate (rGO-SBA/PMMA) composites were fabricated through melt blending method. The structure of the rGO-SBA/PMMA composite was characterized by FTIR, TGA and dynamic mechanical analysis, and the dielectric properties of the composites were tested. The results show that the addition of rGO can increase the glass transition temperature of SBA. At the same time, it can enhance the thermal stability of rGO-SBA composites. Moreover, the addition of rGO significantly increases the dielectric constant of the rGO-SBA composites. rGO-SBA composite possesses the property of high dielectric. For rGO-SBA/PMMA composites, when the SBA content is 13wt% and the rGO content is 0.52wt%, the dielectric constant can approach to 8.79 and the dielectric loss is as low as 0.37 at 1 000 Hz, which further shows that the rGO-SBA/PMMA composites have the characteristics of high dielectric constant and low dielectric loss.
2019, 36(3): 584-591.
doi: 10.13801/j.cnki.fhclxb.20180711.001
Abstract:
The cyclic crosslinking poly(cyclotriphosphazene-co-4,4'-thiobisphenol) (PTP) micro-nano spheres were synthesized using hexachlorocyclotriphosphazene (HCCP) and 4,4'-thiobisphenol (TDP) as raw materials. The obtained PTP spheres were applied in flame retarded epoxy resin (EP) to prepare PTP/EP composites. The PTP spheres were characterized by FTIR and SEM. The thermal stability of PTP/EP composites was investigated by TG, and the flame retardancy was carried out by limiting oxygen index test (LOI) and cone calorimetry (CONE) tests. The results show that the PTP spheres are neither soluble in any organic solvents nor meltable at high temperature. The sphere size is about 500 nm-3 μm and possesses excellent thermal stability and charring ability. The initial decomposition temperature is as high as 453.2℃ and the char residue is 74.3% at 800℃. The addition of PTP spheres can significantly improve the flame retardancy of EP. The peak heat release rate (PHRR) of PTP/EP composite is reduced by 55.43% and the LOI value is increased from 25.6% to 30.4% when merely 5wt% of PTP added. The addition of PTP microspheres also enhanced the mechanical strength of EP. The mechanical strength of PTP/EP composites is also improved with the incorporation of PTP spheres. The PTP spheres can act as a reinforcing agent at room temperature due to the insolubility and infusibility, and also acts as the flame retardant under combustion. The study provides a new ideas and methods for functional flame retardants.
The cyclic crosslinking poly(cyclotriphosphazene-co-4,4'-thiobisphenol) (PTP) micro-nano spheres were synthesized using hexachlorocyclotriphosphazene (HCCP) and 4,4'-thiobisphenol (TDP) as raw materials. The obtained PTP spheres were applied in flame retarded epoxy resin (EP) to prepare PTP/EP composites. The PTP spheres were characterized by FTIR and SEM. The thermal stability of PTP/EP composites was investigated by TG, and the flame retardancy was carried out by limiting oxygen index test (LOI) and cone calorimetry (CONE) tests. The results show that the PTP spheres are neither soluble in any organic solvents nor meltable at high temperature. The sphere size is about 500 nm-3 μm and possesses excellent thermal stability and charring ability. The initial decomposition temperature is as high as 453.2℃ and the char residue is 74.3% at 800℃. The addition of PTP spheres can significantly improve the flame retardancy of EP. The peak heat release rate (PHRR) of PTP/EP composite is reduced by 55.43% and the LOI value is increased from 25.6% to 30.4% when merely 5wt% of PTP added. The addition of PTP microspheres also enhanced the mechanical strength of EP. The mechanical strength of PTP/EP composites is also improved with the incorporation of PTP spheres. The PTP spheres can act as a reinforcing agent at room temperature due to the insolubility and infusibility, and also acts as the flame retardant under combustion. The study provides a new ideas and methods for functional flame retardants.
2019, 36(3): 592-601.
doi: 10.13801/j.cnki.fhclxb.20180529.004
Abstract:
SiO2 hollow microspheres modified Si-containing arylacetylene resin (SiO2/PSAC) casting was prepared to ameliorate the brittleness of cured Si-containing arylacetylene resin and to improve the mechanical properties of the SiO2/PSAC resin casting and to meet the need of the application in the field of aeronautics and astronautics. The structure and properties of the SiO2/PSAC resin casting and quartz fiber reinforced SiO2/PSAC (QF-SiO2/PSAC) composites were investigated. The microstructure of SiO2/PSAC resin castings and QF-SiO2/PSAC composites were observed by SEM, and the toughening mechanism of SiO2 was analyzed. The heat resistance and thermal stability of SiO2/PSAC composites were studied by DMA and TGA. The heat resistance of the resin decreased slightly, but the porous structure made the resin excellent in dielectric properties. Meanwhile, when the content of SiO2 is added to 2wt%, the flexural strength of SiO2/PSAC resin casting is 22.3 MPa. The temperature of decomposition (Td5) is 551℃ and the char yield at 1 000℃ is 86.5%; the flexural strength of QF-2SiO2/PSAC composite is 298.3 MPa, and the modulus reaches 31.0 GPa, which increases by 27.5% and 59.0%, respectively; When the content of SiO2 is 5wt%, the shear strength of QF-5SiO2/PSAC composite increases by 16.0%.
SiO2 hollow microspheres modified Si-containing arylacetylene resin (SiO2/PSAC) casting was prepared to ameliorate the brittleness of cured Si-containing arylacetylene resin and to improve the mechanical properties of the SiO2/PSAC resin casting and to meet the need of the application in the field of aeronautics and astronautics. The structure and properties of the SiO2/PSAC resin casting and quartz fiber reinforced SiO2/PSAC (QF-SiO2/PSAC) composites were investigated. The microstructure of SiO2/PSAC resin castings and QF-SiO2/PSAC composites were observed by SEM, and the toughening mechanism of SiO2 was analyzed. The heat resistance and thermal stability of SiO2/PSAC composites were studied by DMA and TGA. The heat resistance of the resin decreased slightly, but the porous structure made the resin excellent in dielectric properties. Meanwhile, when the content of SiO2 is added to 2wt%, the flexural strength of SiO2/PSAC resin casting is 22.3 MPa. The temperature of decomposition (Td5) is 551℃ and the char yield at 1 000℃ is 86.5%; the flexural strength of QF-2SiO2/PSAC composite is 298.3 MPa, and the modulus reaches 31.0 GPa, which increases by 27.5% and 59.0%, respectively; When the content of SiO2 is 5wt%, the shear strength of QF-5SiO2/PSAC composite increases by 16.0%.
2019, 36(3): 602-610.
doi: 10.13801/j.cnki.fhclxb.20180918.001
Abstract:
The mesocarbon microbeads (MCMBs) with different size and fabrication process (M22, M15 and M23) were fabricated cyanate ester resin (CE) (MCMBs/CE) composites with volume fraction of 10vol%, 25vol%, 40vol% and 50vol% of MCMBs. The MCMBs/CE composites were characterized by SEM, XRD, Raman spectrum, thermal analyzer and resistance instrument. The results indicate that all the three spherical powders have the graphitization structure. Compared to M15 and M23, the M22 filler shows a regular spherical particle, the highest carbonization (ID/IG=0.23) and the lowest volume resistivity. The moisture resistance, thermal conductivity and electrical conductivity of the MCMBs/CE composites are enhanced with the increasing of fillers volume fraction. While, the impact strength of composites presents a marginal reduction with further increase in filler content. The MCMBs/CE composite achieves a low water absorption of 0.45%, a high impact strength of 23.6 kJ/m2, a high thermal conductivity of 1.28 W/(m·K) and a low volume resistivity of 1.5 Ω·cm containing 40vol% M22 filler.
The mesocarbon microbeads (MCMBs) with different size and fabrication process (M22, M15 and M23) were fabricated cyanate ester resin (CE) (MCMBs/CE) composites with volume fraction of 10vol%, 25vol%, 40vol% and 50vol% of MCMBs. The MCMBs/CE composites were characterized by SEM, XRD, Raman spectrum, thermal analyzer and resistance instrument. The results indicate that all the three spherical powders have the graphitization structure. Compared to M15 and M23, the M22 filler shows a regular spherical particle, the highest carbonization (ID/IG=0.23) and the lowest volume resistivity. The moisture resistance, thermal conductivity and electrical conductivity of the MCMBs/CE composites are enhanced with the increasing of fillers volume fraction. While, the impact strength of composites presents a marginal reduction with further increase in filler content. The MCMBs/CE composite achieves a low water absorption of 0.45%, a high impact strength of 23.6 kJ/m2, a high thermal conductivity of 1.28 W/(m·K) and a low volume resistivity of 1.5 Ω·cm containing 40vol% M22 filler.
2019, 36(3): 611-616.
doi: 10.13801/j.cnki.fhclxb.20180911.002
Abstract:
The basalt fiber fabrics modified with self-made rare earth modifiers (La-BF) enhance the bisphenol-A dicyanate (BADCy). The influence of the modification on basalt fiber (BF) surface was analyzed by SEM and FTIR. The effect of the modification on the thermal stability of BF/BADCy composite was investigated by TG analysis. The modification of the BF/BADCy composites with different mass fractions were analyzed using an electronic universal testing machine. Influence of the flexural properties of the material, the influence of the modification on the dielectric properties of the BF/BADCy composites were analyzed by an impedance analyzer. The results show that the modification reduces the surface defects of the BF and introduces crystalline bulges, which is beneficial to improve the interface properties of the BF/BADCy composite. The modification increases the thermal decomposition temperature of the BF/BADCy composite, and the initial decomposition temperature is increased by 145℃. When the mass fraction of BF is 12wt%, the flexural modulus of the La-BF/BADCy composite is improved to 4.19 GPa and the flexural strength is over 110 MPa. In 1 MHz-3 GHz range, the dielectric constant of the La-BF/BADCy composite is around 1.9. Therefore, the rare earth modification can effectively improve the flexural properties, thermal stability and dielectric properties of BF/BADCy composites.
The basalt fiber fabrics modified with self-made rare earth modifiers (La-BF) enhance the bisphenol-A dicyanate (BADCy). The influence of the modification on basalt fiber (BF) surface was analyzed by SEM and FTIR. The effect of the modification on the thermal stability of BF/BADCy composite was investigated by TG analysis. The modification of the BF/BADCy composites with different mass fractions were analyzed using an electronic universal testing machine. Influence of the flexural properties of the material, the influence of the modification on the dielectric properties of the BF/BADCy composites were analyzed by an impedance analyzer. The results show that the modification reduces the surface defects of the BF and introduces crystalline bulges, which is beneficial to improve the interface properties of the BF/BADCy composite. The modification increases the thermal decomposition temperature of the BF/BADCy composite, and the initial decomposition temperature is increased by 145℃. When the mass fraction of BF is 12wt%, the flexural modulus of the La-BF/BADCy composite is improved to 4.19 GPa and the flexural strength is over 110 MPa. In 1 MHz-3 GHz range, the dielectric constant of the La-BF/BADCy composite is around 1.9. Therefore, the rare earth modification can effectively improve the flexural properties, thermal stability and dielectric properties of BF/BADCy composites.
2019, 36(3): 617-623.
doi: 10.13801/j.cnki.fhclxb.20180726.005
Abstract:
The prepolymer method was used to prepare the glass fiber reinforced self-crosslinking polyurethane (GF/PU) composites, in which three functional polyether polyol (PPG) and two phenyl methane diisocyanate (MDI) acted as the soft and hard segments, respectively. The effects of the polymerization temperature of PU prepolymer, pot-life of application, crystallinity and content of GF on the dynamic mechanical and mechanical properties of the GF/PU composites were studied by using rotating viscometer, DMA, SEM, XRD and mechanical testing machine. The results show that the GF/PU composites exhibit the highest performance comprehensive performance when the polymerization temperature of the PU prepolymer is 50℃ and the mass fraction of GF is 55wt%. The tensile strength, flexural strength, and impact toughness of GF/PU composite are 794 MPa, 846 MPa and 228 kJ/m2, respectively. The peak value of dynamic mechanical properties loss factor (tanδ) is 0.59.
The prepolymer method was used to prepare the glass fiber reinforced self-crosslinking polyurethane (GF/PU) composites, in which three functional polyether polyol (PPG) and two phenyl methane diisocyanate (MDI) acted as the soft and hard segments, respectively. The effects of the polymerization temperature of PU prepolymer, pot-life of application, crystallinity and content of GF on the dynamic mechanical and mechanical properties of the GF/PU composites were studied by using rotating viscometer, DMA, SEM, XRD and mechanical testing machine. The results show that the GF/PU composites exhibit the highest performance comprehensive performance when the polymerization temperature of the PU prepolymer is 50℃ and the mass fraction of GF is 55wt%. The tensile strength, flexural strength, and impact toughness of GF/PU composite are 794 MPa, 846 MPa and 228 kJ/m2, respectively. The peak value of dynamic mechanical properties loss factor (tanδ) is 0.59.
2019, 36(3): 624-629.
doi: 10.13801/j.cnki.fhclxb.20180911.003
Abstract:
The SiO2/polytetrafluoroethylene (PTFE) composite films with 35wt% SiO2 and the thickness of 50 μm were prepared by air-assisted dry blending, cold-pressing, sintering and skiving techniques. The effects of SiO2 particle size on the pinhole defects and mechanical properties for SiO2/PTFE composite films were investigated, and the influence of the dispersion of SiO2 in PTFE and the intermolecular interaction on the mechanism of its performance was also studied. The results show that with the increasing of SiO2 particle size, the dispersion throughout the PTFE matrix tends to be uniform, and PTFE can coat the particles better. The pinhole defects of the SiO2/PTFE composite films are reduced and the mechanical properties are improved. When the particle size (D50) of SiO2 is 12 μm, the distribution in the PTFE matrix is most uniform, the pinhole defects are least, and the PTFE/SiO2 composite film exhibits optimum mechanical properties. The elongation at break is 19.5%, and the tensile strength is 9.2 MPa.
The SiO2/polytetrafluoroethylene (PTFE) composite films with 35wt% SiO2 and the thickness of 50 μm were prepared by air-assisted dry blending, cold-pressing, sintering and skiving techniques. The effects of SiO2 particle size on the pinhole defects and mechanical properties for SiO2/PTFE composite films were investigated, and the influence of the dispersion of SiO2 in PTFE and the intermolecular interaction on the mechanism of its performance was also studied. The results show that with the increasing of SiO2 particle size, the dispersion throughout the PTFE matrix tends to be uniform, and PTFE can coat the particles better. The pinhole defects of the SiO2/PTFE composite films are reduced and the mechanical properties are improved. When the particle size (D50) of SiO2 is 12 μm, the distribution in the PTFE matrix is most uniform, the pinhole defects are least, and the PTFE/SiO2 composite film exhibits optimum mechanical properties. The elongation at break is 19.5%, and the tensile strength is 9.2 MPa.
2019, 36(3): 630-637.
doi: 10.13801/j.cnki.fhclxb.20180911.001
Abstract:
Calcium lignosulfonate (CL) was used to fill high density polyethylene (HDPE) to prepare CL/HDPE composites, the composites were characterized by SEM, DSC, XRD, and the mechanical properties such as strength, creep behavior and stress relaxation of CL/HDPE composites were tested. The results show that the CL/HDPE composites have good the bonding interface and the thermal stability; the addition of CL can improve the flexural strength, but it can lead a negative effect on the impact strength of CL/HDPE composites; the increase of CL content can improve the creep resistance and stress relaxation, but the increase of temperature can lead a negative effect on the creep behavior and stress relaxation of CL/HDPE composites.
Calcium lignosulfonate (CL) was used to fill high density polyethylene (HDPE) to prepare CL/HDPE composites, the composites were characterized by SEM, DSC, XRD, and the mechanical properties such as strength, creep behavior and stress relaxation of CL/HDPE composites were tested. The results show that the CL/HDPE composites have good the bonding interface and the thermal stability; the addition of CL can improve the flexural strength, but it can lead a negative effect on the impact strength of CL/HDPE composites; the increase of CL content can improve the creep resistance and stress relaxation, but the increase of temperature can lead a negative effect on the creep behavior and stress relaxation of CL/HDPE composites.
2019, 36(3): 638-645.
doi: 10.13801/j.cnki.fhclxb.20180530.006
Abstract:
The continuous aramid fiber(CAF) was added to wood flour/high density polyethylene(WF/HDPE) composites by screw extruder. Surface treatment of CAF with phosphoric acid and silane coupling agent was used to improve the interfacial compatibility between CAF and the WF/HDPE composites. The morphological analysis showed that the surface roughness of CAF increased after the surface treatment. Either the treatment of CAF with phosphoric acid or silane coupling agent, the pull-out strength of CAF bundle increases up to 94.9% and 77.6%, respectively. It shows that the interfacial bonding strength of the treated CAF and the WF/HDPE composites is enhanced. Compared with WF/HDPE composite without CAF, the composite with the untreated CAF results in that the tensile strength, flexural strength and impact strength of CAF-WF/HDPE composite increases by 32.1%, 35.1% and 515.1%, respectively. After CAF treated with silane coupling agent, the mechanical properties of CAF-WF/HDPE composite increase by 42.0%, 37.4% and 550.2%. The dynamic mechanical analysis shows that the interfacial compatibility of the CAF and WF/HDPE composite is improved after surface treatment.
The continuous aramid fiber(CAF) was added to wood flour/high density polyethylene(WF/HDPE) composites by screw extruder. Surface treatment of CAF with phosphoric acid and silane coupling agent was used to improve the interfacial compatibility between CAF and the WF/HDPE composites. The morphological analysis showed that the surface roughness of CAF increased after the surface treatment. Either the treatment of CAF with phosphoric acid or silane coupling agent, the pull-out strength of CAF bundle increases up to 94.9% and 77.6%, respectively. It shows that the interfacial bonding strength of the treated CAF and the WF/HDPE composites is enhanced. Compared with WF/HDPE composite without CAF, the composite with the untreated CAF results in that the tensile strength, flexural strength and impact strength of CAF-WF/HDPE composite increases by 32.1%, 35.1% and 515.1%, respectively. After CAF treated with silane coupling agent, the mechanical properties of CAF-WF/HDPE composite increase by 42.0%, 37.4% and 550.2%. The dynamic mechanical analysis shows that the interfacial compatibility of the CAF and WF/HDPE composite is improved after surface treatment.
2019, 36(3): 646-653.
doi: 10.13801/j.cnki.fhclxb.20180726.003
Abstract:
Loose and porous nano CoFe2O4-reduced graphene oxide (CoFe2O4-rGO) composites were prepared via in situ solvothermal method, using graphene oxide (GO), Co2+ and Fe3+ as the raw materials. XRD, Raman, SEM and HRTEM were employed to characterize the structure and morphology of nano CoFe2O4-rGO composites. The results show that nano CoFe2O4-rGO composites exhibit 3D structure. The self-assembled porous nanospheres with a diameter of about 200 nm are uniformly dispersed on rGO, which solves the agglomeration of CoFe2O4. The electrochemical test results show that nano CoFe2O4-rGO composites deliver a comparatively high specific capacity and excellent cycle and rate performance. The specific capacity reaches 1 262 mAh·g-1 at a current density of 100 mA·g-1, which can still maintain at 642 mAh·g-1 after 50 cycles. The specific capacity reaches 221 mAh·g-1 at a high current density of 2 000 mA·g-1. The enhanced electrochemical performance of nano CoFe2O4-rGO composites results from the homogenous distribution of CoFe2O4 nanospheres on rGO. The 3D structure provides more active sites of Li+ storage, and thus effectively relieve the volume shrinkage/expansion of the electrodes, which in return improve the conductivity of nano CoFe2O4-rGO composites.
Loose and porous nano CoFe2O4-reduced graphene oxide (CoFe2O4-rGO) composites were prepared via in situ solvothermal method, using graphene oxide (GO), Co2+ and Fe3+ as the raw materials. XRD, Raman, SEM and HRTEM were employed to characterize the structure and morphology of nano CoFe2O4-rGO composites. The results show that nano CoFe2O4-rGO composites exhibit 3D structure. The self-assembled porous nanospheres with a diameter of about 200 nm are uniformly dispersed on rGO, which solves the agglomeration of CoFe2O4. The electrochemical test results show that nano CoFe2O4-rGO composites deliver a comparatively high specific capacity and excellent cycle and rate performance. The specific capacity reaches 1 262 mAh·g-1 at a current density of 100 mA·g-1, which can still maintain at 642 mAh·g-1 after 50 cycles. The specific capacity reaches 221 mAh·g-1 at a high current density of 2 000 mA·g-1. The enhanced electrochemical performance of nano CoFe2O4-rGO composites results from the homogenous distribution of CoFe2O4 nanospheres on rGO. The 3D structure provides more active sites of Li+ storage, and thus effectively relieve the volume shrinkage/expansion of the electrodes, which in return improve the conductivity of nano CoFe2O4-rGO composites.
2019, 36(3): 654-660.
doi: 10.13801/j.cnki.fhclxb.20180911.004
Abstract:
The Mg/NiTi composites were prepared by pressureless infiltration of Mg powders to improve the strength and damping capacity of porous NiTi alloys. The microstructure of the Mg/NiTi composites were investiaged by OM, SEM, EDS and XRD, the compressive strength and energy absorption ability were analyzed by compressive test and the internal friction and storage modulus were tested by the thermal mechanical analyzer. The results show that the pores of the porous NiTi alloy are filled by Mg through the pressureless infiltration of Mg powders, and the porosity decreases from 50.38% to 5.6% for Mg/NiTi composites. Moreover, the interface bonding of Mg and NiTi alloy is good. The porous NiTi alloys are mainly composed of B2 austenite phase and B19' martensite phase with a few Ni3Ti and NiTi2 phases, while the Mg/NiTi composites are composed of infiltrated Mg phase and newly generated Mg2Ni phase except the phases contained in the porous NiTi alloys. The transformation behavior of the porous NiTi alloys does not change but the transformation temperatures increase after the infiltration of Mg. The compressive strength of the Mg/NiTi composites is up to 554 MPa, 61% higher than that of the porous NiTi alloys. The compression fracture mode also changes from the pore wall collapsed fracture of the porous NiTi alloy to the shear fracture of the Mg/NiTi composites. The energy absorption ability of the Mg/NiTi is greatly improved compared to the porous NiTi alloys. At the same time, the internal friction value of Mg/NiTi composites has a little increase, while the storage modulus is significantly improved, presenting much better damping capacity.
The Mg/NiTi composites were prepared by pressureless infiltration of Mg powders to improve the strength and damping capacity of porous NiTi alloys. The microstructure of the Mg/NiTi composites were investiaged by OM, SEM, EDS and XRD, the compressive strength and energy absorption ability were analyzed by compressive test and the internal friction and storage modulus were tested by the thermal mechanical analyzer. The results show that the pores of the porous NiTi alloy are filled by Mg through the pressureless infiltration of Mg powders, and the porosity decreases from 50.38% to 5.6% for Mg/NiTi composites. Moreover, the interface bonding of Mg and NiTi alloy is good. The porous NiTi alloys are mainly composed of B2 austenite phase and B19' martensite phase with a few Ni3Ti and NiTi2 phases, while the Mg/NiTi composites are composed of infiltrated Mg phase and newly generated Mg2Ni phase except the phases contained in the porous NiTi alloys. The transformation behavior of the porous NiTi alloys does not change but the transformation temperatures increase after the infiltration of Mg. The compressive strength of the Mg/NiTi composites is up to 554 MPa, 61% higher than that of the porous NiTi alloys. The compression fracture mode also changes from the pore wall collapsed fracture of the porous NiTi alloy to the shear fracture of the Mg/NiTi composites. The energy absorption ability of the Mg/NiTi is greatly improved compared to the porous NiTi alloys. At the same time, the internal friction value of Mg/NiTi composites has a little increase, while the storage modulus is significantly improved, presenting much better damping capacity.
2019, 36(3): 661-668.
doi: 10.13801/j.cnki.fhclxb.20180530.007
Abstract:
The in-situ TiB2/Fe composites were synthesized by microwave sintering. The isothermal oxidation behavior of TiB2/Fe composites was investigated in air at 500℃, 600℃ and 700℃. The surface, cross-sectional morphology and phase composition of the oxide films were also analyzed. The results show that the in-situ TiB2/Fe composites are composed of TiB2, Fe2B and α-Fe phases. With the oxidation temperatures increasing, the oxidation weight of TiB2/Fe composites increases obviously and shows the law of parabolic. At 500℃, the main oxidation products of the composites are Fe2O3 and Fe3O4. At 700℃, the oxides are composed of Fe2O3, TiO2, Fe9TiO15 and Fe3BO6. With the increase of TiB2 contents, the oxide particle size, oxidation mass and oxide layer thickness of TiB2/Fe composites decrease at the same temperature, and the oxidation activation energy increases, which leads to the improvement of the oxidation resistance of TiB2/Fe composites.
The in-situ TiB2/Fe composites were synthesized by microwave sintering. The isothermal oxidation behavior of TiB2/Fe composites was investigated in air at 500℃, 600℃ and 700℃. The surface, cross-sectional morphology and phase composition of the oxide films were also analyzed. The results show that the in-situ TiB2/Fe composites are composed of TiB2, Fe2B and α-Fe phases. With the oxidation temperatures increasing, the oxidation weight of TiB2/Fe composites increases obviously and shows the law of parabolic. At 500℃, the main oxidation products of the composites are Fe2O3 and Fe3O4. At 700℃, the oxides are composed of Fe2O3, TiO2, Fe9TiO15 and Fe3BO6. With the increase of TiB2 contents, the oxide particle size, oxidation mass and oxide layer thickness of TiB2/Fe composites decrease at the same temperature, and the oxidation activation energy increases, which leads to the improvement of the oxidation resistance of TiB2/Fe composites.
2019, 36(3): 669-676.
doi: 10.13801/j.cnki.fhclxb.20180530.005
Abstract:
Diamond/Al, diamond/AlSi7 and diamond/AlSi9 composites were fabricated by using gas pressure infiltration, and the decline behaviors for the thermal conductivity of the composites when exposed to the air were analyzed. The results show that the reaction product Al4C3 between the diamond and the molten Al can decompose into Al(OH)3 in the humid air, resulting in the decline for the thermal conductivity of diamond/Al composites. Adding element Si into Al is found to inhibit the decline rate effectively, the mechanism of which are as follows:decrease in the amount of Al4C3 because of the decrease in the solubility of C of diamond in molten Al and the preferential precipitation of eutectic Si on diamond; increase in the density of the diamond/AlSi composites to prevent the contact between Al4C3 and moisture. Some methods of inhibiting the decline of the thermal conductivity of diamond/Al composites were also discussed, which is hopeful to prolong the service time of the composites in humid environment.
Diamond/Al, diamond/AlSi7 and diamond/AlSi9 composites were fabricated by using gas pressure infiltration, and the decline behaviors for the thermal conductivity of the composites when exposed to the air were analyzed. The results show that the reaction product Al4C3 between the diamond and the molten Al can decompose into Al(OH)3 in the humid air, resulting in the decline for the thermal conductivity of diamond/Al composites. Adding element Si into Al is found to inhibit the decline rate effectively, the mechanism of which are as follows:decrease in the amount of Al4C3 because of the decrease in the solubility of C of diamond in molten Al and the preferential precipitation of eutectic Si on diamond; increase in the density of the diamond/AlSi composites to prevent the contact between Al4C3 and moisture. Some methods of inhibiting the decline of the thermal conductivity of diamond/Al composites were also discussed, which is hopeful to prolong the service time of the composites in humid environment.
2019, 36(3): 677-684.
doi: 10.13801/j.cnki.fhclxb.20180530.003
Abstract:
In order to improve the high temperature properties of low grade magnesium-based material, Mg-α-SiAlON/MgO composites were prepared using sintered magnesia, Al metal powder, Si powder and Al2O3 powder as the raw material, the Mg-α-SiAlON phase in-situ forming in the Mg-α-SiAlON/MgO composites sintered at different temperature and mass fraction were determined by XRD, SEM and EDS. The synthesis atmosphere conditions of Mg-α-SiAlON were determined by thermodynamic analysis and the reaction mechanism of Mg-α-SiAlON phase were explained. The experiment results show that the partial pressure of nitrogen and oxygen at 1 550℃ satisfies the thermodynamic requirement for the synthesis of Mg-α-SiAlON. When the total mass fraction of sintered magnesia powder, Al metal powder, Si powder and Al2O3 powder is 40wt%, the content of Mg-α-SiAlON phase with plate-like shape is as high as 32.1% in Mg-α-SiAlON/MgO composites nitrided at 1 550℃ for 3 h. Mg-α-SiAlON phase interlace to form a skeleton and envelope the low melting phase inside of it. The in-situ synthesis of Mg-α-SiAlON/MgO composites from sintered magnesia by nitridation is beneficial for improving the thermal shock resistance of magnesium-based material.
In order to improve the high temperature properties of low grade magnesium-based material, Mg-α-SiAlON/MgO composites were prepared using sintered magnesia, Al metal powder, Si powder and Al2O3 powder as the raw material, the Mg-α-SiAlON phase in-situ forming in the Mg-α-SiAlON/MgO composites sintered at different temperature and mass fraction were determined by XRD, SEM and EDS. The synthesis atmosphere conditions of Mg-α-SiAlON were determined by thermodynamic analysis and the reaction mechanism of Mg-α-SiAlON phase were explained. The experiment results show that the partial pressure of nitrogen and oxygen at 1 550℃ satisfies the thermodynamic requirement for the synthesis of Mg-α-SiAlON. When the total mass fraction of sintered magnesia powder, Al metal powder, Si powder and Al2O3 powder is 40wt%, the content of Mg-α-SiAlON phase with plate-like shape is as high as 32.1% in Mg-α-SiAlON/MgO composites nitrided at 1 550℃ for 3 h. Mg-α-SiAlON phase interlace to form a skeleton and envelope the low melting phase inside of it. The in-situ synthesis of Mg-α-SiAlON/MgO composites from sintered magnesia by nitridation is beneficial for improving the thermal shock resistance of magnesium-based material.
2019, 36(3): 685-692.
doi: 10.13801/j.cnki.fhclxb.20180530.008
Abstract:
In order to achieve a better close shade of artificial restoration match with natural dentition, a color-gradient 3 mol% Y2O3-stabilized ZrO2 (3Y-TZP) ceramics for dental restoration was prepared by forming and sintering process with powders of Fe2O3 (0.01wt%-0.09wt%)-Al2O3 (0.1wt%)/3Y-TZP as the raw materials. Their colorimetric characterization, sintering performance, and mechanical properties were tested, and the effect of Fe2O3 and Al2O3 on 3Y-TZP ceramics was studied. The results show that the color of the gradient Al2O3-Fe2O3/3Y-TZP changing from saffron yellow to white gradually, which matches with the natural dentition. In addition, the doping of trace Al2O3 (0.1wt%) on uncolored porcelain layer can avoid the cracking between porcelain layers during the presintering process. The flexural strength changes of gradient and can meet the need of dental restoration (≥ 800 MPa). The doping of trace Fe2O3 (0.01wt%) and Al2O3 (0.1wt%) can improve the densification and grain growth during the sintering process. And the doping of trace Fe2O3 (0.01wt%) and Al2O3 (0.1wt%) in 3Y-TZP can increase the flexural strength of the Al2O3-Fe2O3/3Y-TZP, but the flexural strength decreases when more Fe2O3 is doped (≤ 0.09wt%) in 3Y-TZP.
In order to achieve a better close shade of artificial restoration match with natural dentition, a color-gradient 3 mol% Y2O3-stabilized ZrO2 (3Y-TZP) ceramics for dental restoration was prepared by forming and sintering process with powders of Fe2O3 (0.01wt%-0.09wt%)-Al2O3 (0.1wt%)/3Y-TZP as the raw materials. Their colorimetric characterization, sintering performance, and mechanical properties were tested, and the effect of Fe2O3 and Al2O3 on 3Y-TZP ceramics was studied. The results show that the color of the gradient Al2O3-Fe2O3/3Y-TZP changing from saffron yellow to white gradually, which matches with the natural dentition. In addition, the doping of trace Al2O3 (0.1wt%) on uncolored porcelain layer can avoid the cracking between porcelain layers during the presintering process. The flexural strength changes of gradient and can meet the need of dental restoration (≥ 800 MPa). The doping of trace Fe2O3 (0.01wt%) and Al2O3 (0.1wt%) can improve the densification and grain growth during the sintering process. And the doping of trace Fe2O3 (0.01wt%) and Al2O3 (0.1wt%) in 3Y-TZP can increase the flexural strength of the Al2O3-Fe2O3/3Y-TZP, but the flexural strength decreases when more Fe2O3 is doped (≤ 0.09wt%) in 3Y-TZP.
Adsorption and photocatalytic properties of V-N-TiO2/attapulgite and V-N-TiO2/glass beads composites
2019, 36(3): 693-700.
doi: 10.13801/j.cnki.fhclxb.20180704.001
Abstract:
The adsorption characteristics and photocatalytic properties of self-developed V-N-TiO2, V-N-TiO2/attapulgite and V-N-TiO2/glass beads composites were studied. The humic acid, methylene blue, and dimethylformamide were used as the target degradants. The results show that the adsorption of humic acid and methylene blue except dimethylformamide by V-N-TiO2, V-N-TiO2/attapulgite and V-N-TiO2/glass beads composites, attapulgite, glass beads conforms to the Langmuir isotherm model. The loading form of V-N-TiO2/attapulgite and V-N-TiO2/glass beads composites has the greatest influence on its adsorption performance. All photocatalytic reactions of humic acid and methylene blue by V-N-TiO2, V-N-TiO2/attapulgite and V-N-TiO2/glass beads composites are consistent with the first-order kinetic equation. The photocatalytic property of V-N-TiO2/attapulgite and V-N-TiO2/glass beads composites is related to the adsorption equilibrium constant Ka and the photocatalytic surface reaction rate constant Kr. When the composite has a large difference in the value of the adsorption equilibrium constant for different target degradation products, the greater the adsorption equilibrium constant, the greater the reaction rate constant, the faster the photocatalytic reaction proceeds. When the composite does not differ greatly in the value of the adsorption equilibrium constant for different target degradation products, the greater the photocatalytic surface reaction rate constant, the greater the reaction rate constant, and the faster the photocatalytic reaction proceeds.
The adsorption characteristics and photocatalytic properties of self-developed V-N-TiO2, V-N-TiO2/attapulgite and V-N-TiO2/glass beads composites were studied. The humic acid, methylene blue, and dimethylformamide were used as the target degradants. The results show that the adsorption of humic acid and methylene blue except dimethylformamide by V-N-TiO2, V-N-TiO2/attapulgite and V-N-TiO2/glass beads composites, attapulgite, glass beads conforms to the Langmuir isotherm model. The loading form of V-N-TiO2/attapulgite and V-N-TiO2/glass beads composites has the greatest influence on its adsorption performance. All photocatalytic reactions of humic acid and methylene blue by V-N-TiO2, V-N-TiO2/attapulgite and V-N-TiO2/glass beads composites are consistent with the first-order kinetic equation. The photocatalytic property of V-N-TiO2/attapulgite and V-N-TiO2/glass beads composites is related to the adsorption equilibrium constant Ka and the photocatalytic surface reaction rate constant Kr. When the composite has a large difference in the value of the adsorption equilibrium constant for different target degradation products, the greater the adsorption equilibrium constant, the greater the reaction rate constant, the faster the photocatalytic reaction proceeds. When the composite does not differ greatly in the value of the adsorption equilibrium constant for different target degradation products, the greater the photocatalytic surface reaction rate constant, the greater the reaction rate constant, and the faster the photocatalytic reaction proceeds.
2019, 36(3): 701-707.
doi: 10.13801/j.cnki.fhclxb.20180529.003
Abstract:
The optimum preparation method of chitosan/zeolite molecular sieve composite adsorbed particles was confirmed through the modified conditions for the removal of NH4+-N and NO3--N simultaneously. And the surface physicochemical properties of the chitosan/zeolite molecular sieve composite adsorbed particles were analyzed by SEM, specific surface area (BET), FTIR and XPS, respectively. The results show that when the mixed solution of acetic acid and chitosan with the concentration of 4vol% and 7 g/L is vibrated for 10 h at the temperature of 30℃, the adsorption capacity of the prepared chitosan/zeolite molecular sieve particles for NH4+-N and NO3--N is 0.636 mg/g and 1.952 mg/g and the removal rate reachs 81.60% and 40.28%, respectively. More protrusions and micropores are also found on the surface of chitosan/zeolite molecular sieve particles with the specific surface area of 391.52 m2/g. FTIR analysis shows that -NH2 and -CH3, the characteristic function groups of chitosan are already loaded into the basic framework of zeolite molecular sieve and the XPS analysis indicates that the element O1s plays an important role in the attachment of chitosan to zeolite molecular sieves. The findings of the research can provide a theoretical basis for the upgrading of water purification plant in the northern cold region.
The optimum preparation method of chitosan/zeolite molecular sieve composite adsorbed particles was confirmed through the modified conditions for the removal of NH4+-N and NO3--N simultaneously. And the surface physicochemical properties of the chitosan/zeolite molecular sieve composite adsorbed particles were analyzed by SEM, specific surface area (BET), FTIR and XPS, respectively. The results show that when the mixed solution of acetic acid and chitosan with the concentration of 4vol% and 7 g/L is vibrated for 10 h at the temperature of 30℃, the adsorption capacity of the prepared chitosan/zeolite molecular sieve particles for NH4+-N and NO3--N is 0.636 mg/g and 1.952 mg/g and the removal rate reachs 81.60% and 40.28%, respectively. More protrusions and micropores are also found on the surface of chitosan/zeolite molecular sieve particles with the specific surface area of 391.52 m2/g. FTIR analysis shows that -NH2 and -CH3, the characteristic function groups of chitosan are already loaded into the basic framework of zeolite molecular sieve and the XPS analysis indicates that the element O1s plays an important role in the attachment of chitosan to zeolite molecular sieves. The findings of the research can provide a theoretical basis for the upgrading of water purification plant in the northern cold region.
2019, 36(3): 708-714.
doi: 10.13801/j.cnki.fhclxb.20180613.004
Abstract:
In order to improve the dispersion degree of graphene oxide (GO)/Fe3O4 composites, modified graphene oxide (GOP) was obtained by functional modification of GO surface with triphenylphosphine (PPh3). GOP/Fe3O4 composites was synthesized in one step by coprecipitation method. The morphologies, structures and magnetic properties of GOP/Fe3O4 composites were characterized by SEM, TEM, XRD, FTIR, Raman and VSM. The electromagnetic parameters of the GOP/Fe3O4 composites were measured by phasor network analyzer (PNA), and the electromagnetic wave absorption properties of GOP/Fe3O4 composites were simulated. The results show that the maximum absorption peak value of GOP/Fe3O4 composites is -25.4 dB and the maximum absorption bandwidth is 6.0 GHz, which is greatly improved compared with the unmodified GO/Fe3O4 composites.
In order to improve the dispersion degree of graphene oxide (GO)/Fe3O4 composites, modified graphene oxide (GOP) was obtained by functional modification of GO surface with triphenylphosphine (PPh3). GOP/Fe3O4 composites was synthesized in one step by coprecipitation method. The morphologies, structures and magnetic properties of GOP/Fe3O4 composites were characterized by SEM, TEM, XRD, FTIR, Raman and VSM. The electromagnetic parameters of the GOP/Fe3O4 composites were measured by phasor network analyzer (PNA), and the electromagnetic wave absorption properties of GOP/Fe3O4 composites were simulated. The results show that the maximum absorption peak value of GOP/Fe3O4 composites is -25.4 dB and the maximum absorption bandwidth is 6.0 GHz, which is greatly improved compared with the unmodified GO/Fe3O4 composites.
2019, 36(3): 715-722.
doi: 10.13801/j.cnki.fhclxb.20180821.006
Abstract:
A single-side highhydrophobic fluorinated silica/poly(ether sulfone) (fSiO2/PES) composite membrane was prepared by vacuum-filtrating with tetraethoxysilian (TEOS) and perfluorodecyltriethoxysilane (PFDTES) as the silica source. The chemical component and morphology of the single-side highhydrophobic fSiO2/PES composite membrane was examined by ATR-FTIR, XPS, TEM and FESEM, individually. The effects of PFDTES modification amount and the heat treatment condition on membrane hydrophobicity were investigated, and the hydrophobic stability of fSiO2/PES composite membrane was evaluated. The results show that the water contact angle of the single-side highhydrophobic fSiO2/PES composite membrane is 131.5° when the mass ratio of PFDTES:TEOS is 3. The water contact angle of the single-side highhydrophobic fSiO2/PES composite membrane is 138.9°, as the heat treatment temperature is 100℃ and the heat treatment time is 4 h. In addition, the single-side highhydrophobic fSiO2/PES composite membrane exhibits excellent hydrophobic stable performance.
A single-side highhydrophobic fluorinated silica/poly(ether sulfone) (fSiO2/PES) composite membrane was prepared by vacuum-filtrating with tetraethoxysilian (TEOS) and perfluorodecyltriethoxysilane (PFDTES) as the silica source. The chemical component and morphology of the single-side highhydrophobic fSiO2/PES composite membrane was examined by ATR-FTIR, XPS, TEM and FESEM, individually. The effects of PFDTES modification amount and the heat treatment condition on membrane hydrophobicity were investigated, and the hydrophobic stability of fSiO2/PES composite membrane was evaluated. The results show that the water contact angle of the single-side highhydrophobic fSiO2/PES composite membrane is 131.5° when the mass ratio of PFDTES:TEOS is 3. The water contact angle of the single-side highhydrophobic fSiO2/PES composite membrane is 138.9°, as the heat treatment temperature is 100℃ and the heat treatment time is 4 h. In addition, the single-side highhydrophobic fSiO2/PES composite membrane exhibits excellent hydrophobic stable performance.
2019, 36(3): 723-729.
doi: 10.13801/j.cnki.fhclxb.20180911.007
Abstract:
In order to obtain flexible high-conductivity conductive materials, a novel conductive film of bacterial cellulose@polypyrrole-single wall carbon nanotubes(BC@PPy-SWCNTs) composite films was prepared by simple in situ oxidative polymerization and vacuum filtration using BC, pyrrole (Py) and SWCNTs as the raw materials without any adhesive. The surface morphology and chemical composition of BC@PPy-SWCNTs composite films were characterized by SEM and FTIR. The electrochemical properties of BC@PPy-SWCNTs composite films were studied. The results demonstrate that when the 4.7% mass ratio of SWCNTs is added, the conductivity of BC@PPy-SWCNTs film can reach 6.42 S·cm-1, which is much higher than that of BC@PPy film. When the charging current is 5 mA·cm-2, the area capacitance of BC@PPy-SWCNTs composite films can reach 0.53 F·cm-2 with an energy density of 0.036 mWh·cm-2 and a power density of 1.75 mW·cm-2, respectively. The film widens the variety of BC@PPy-SWCNTs composite films electrode composite films, which has a great possibility for use in supercapacitors, batteries, and sensors.
In order to obtain flexible high-conductivity conductive materials, a novel conductive film of bacterial cellulose@polypyrrole-single wall carbon nanotubes(BC@PPy-SWCNTs) composite films was prepared by simple in situ oxidative polymerization and vacuum filtration using BC, pyrrole (Py) and SWCNTs as the raw materials without any adhesive. The surface morphology and chemical composition of BC@PPy-SWCNTs composite films were characterized by SEM and FTIR. The electrochemical properties of BC@PPy-SWCNTs composite films were studied. The results demonstrate that when the 4.7% mass ratio of SWCNTs is added, the conductivity of BC@PPy-SWCNTs film can reach 6.42 S·cm-1, which is much higher than that of BC@PPy film. When the charging current is 5 mA·cm-2, the area capacitance of BC@PPy-SWCNTs composite films can reach 0.53 F·cm-2 with an energy density of 0.036 mWh·cm-2 and a power density of 1.75 mW·cm-2, respectively. The film widens the variety of BC@PPy-SWCNTs composite films electrode composite films, which has a great possibility for use in supercapacitors, batteries, and sensors.
2019, 36(3): 730-738.
doi: 10.13801/j.cnki.fhclxb.20180911.006
Abstract:
The multi-walled carbon nanotubes/stearic acid-octadecyl alcohol@urea formaldehyde resin (MWCNTs/SA-OA@UF) phase change microcapsules with SA-OA eutectic composite phase change materials(at the mass ratio of 50.02%, phase change temperature was 55℃) as core material, UF modified by melamine as wall material and amino multi-walled carbon nanotubes (MWCNTs-NH2) as highly thermally conductive filler were prepared by using in-situ polymerization method. The chemical structure, morphology, thermal properties and thermal conductivity of the MWCNTs/SA-OA@UF phase change microcapsules were characterized by FTIR, SEM, DSC, TGA and thermal conductivity meter. The effects of different MWCNT modification methods, different types of emulsifiers and the amount of MWCNTs-NH2 added in the SA-OA@UF phase change microcapsules were discussed. The results show that the MWCNTs-NH2 have good dispersibility in the solution; The compounded emulsifiers of sodium dodecyl benzene sulfonate(SDBS) and Triton X-100 make the surface morphology of the SA-OA@UF phase change microcapsules smoother and smoother; The addition of MWCNTs-NH2 with the mass ratio of 0.5% make the MWCNTs/SA-OA@UF phase change microcapsule's thermal conductivity reaches 0.224 W/(m·K), which increases by 38% (55℃), the coating rate increases by 6.9%, the particle size is more uniform and the thermal stability is significantly improved.
The multi-walled carbon nanotubes/stearic acid-octadecyl alcohol@urea formaldehyde resin (MWCNTs/SA-OA@UF) phase change microcapsules with SA-OA eutectic composite phase change materials(at the mass ratio of 50.02%, phase change temperature was 55℃) as core material, UF modified by melamine as wall material and amino multi-walled carbon nanotubes (MWCNTs-NH2) as highly thermally conductive filler were prepared by using in-situ polymerization method. The chemical structure, morphology, thermal properties and thermal conductivity of the MWCNTs/SA-OA@UF phase change microcapsules were characterized by FTIR, SEM, DSC, TGA and thermal conductivity meter. The effects of different MWCNT modification methods, different types of emulsifiers and the amount of MWCNTs-NH2 added in the SA-OA@UF phase change microcapsules were discussed. The results show that the MWCNTs-NH2 have good dispersibility in the solution; The compounded emulsifiers of sodium dodecyl benzene sulfonate(SDBS) and Triton X-100 make the surface morphology of the SA-OA@UF phase change microcapsules smoother and smoother; The addition of MWCNTs-NH2 with the mass ratio of 0.5% make the MWCNTs/SA-OA@UF phase change microcapsule's thermal conductivity reaches 0.224 W/(m·K), which increases by 38% (55℃), the coating rate increases by 6.9%, the particle size is more uniform and the thermal stability is significantly improved.
2019, 36(3): 739-747.
doi: 10.13801/j.cnki.fhclxb.20180821.005
Abstract:
The ternary metallic Ni-Mg-Al oxide (TMO) was synthesized by a homogeneous precipitation method. The carbon nanotubes/3D graphene composites (CNTs/3DGR) were synthesized on the TMO by chemical vapor deposition(CVD) method using CH4 as carbon source and Ar as protective gas. Herein, CNTs were grown on the in-situ reduced Ni nanoparticles, and the 3DGR was grown over the metallic composite oxides of Mg and Al. After etching the metal oxides, the CNTs/3DGR composite was obtained. The structure and performance of CNTs/3DGR were optimized by controlling the parameters during the precipitation of TMO and the CVD reaction of CNTs/3DGR, such as the metal ion molar ratio, growth temperature and growth time. TEM, SEM, EDS, Raman and XRD were employed to demonstrate the structure, morphology and composition of CNTs/3DGR composite. The results support that the synergistic roles of CNTs and GR contribute to give more paves for the electron transport, which promotes the electronic conductivity to improve the capacitance performance significantly with a specific capacitance of 20 F/g.
The ternary metallic Ni-Mg-Al oxide (TMO) was synthesized by a homogeneous precipitation method. The carbon nanotubes/3D graphene composites (CNTs/3DGR) were synthesized on the TMO by chemical vapor deposition(CVD) method using CH4 as carbon source and Ar as protective gas. Herein, CNTs were grown on the in-situ reduced Ni nanoparticles, and the 3DGR was grown over the metallic composite oxides of Mg and Al. After etching the metal oxides, the CNTs/3DGR composite was obtained. The structure and performance of CNTs/3DGR were optimized by controlling the parameters during the precipitation of TMO and the CVD reaction of CNTs/3DGR, such as the metal ion molar ratio, growth temperature and growth time. TEM, SEM, EDS, Raman and XRD were employed to demonstrate the structure, morphology and composition of CNTs/3DGR composite. The results support that the synergistic roles of CNTs and GR contribute to give more paves for the electron transport, which promotes the electronic conductivity to improve the capacitance performance significantly with a specific capacitance of 20 F/g.
2019, 36(3): 748-755.
doi: 10.13801/j.cnki.fhclxb.20180514.001
Abstract:
Small amount of multi-walled carbon nanotubes (MWCNTs) was mixed with certain content of WS2 to fabricate a composite filler, then mixing which with ethylene propylene diene monomer (EPDM) to get the MWCNTs-WS2/EPDM composites with different MWCNTs content. The composite samples were prepared by using a mixing process and the nonlinear conductivity, direct current dielectric breakdown strength and thermal conductivity of MWCNTs-WS2/EPDM composites were investigated. The results show that with the help of WS2, very small amount of MWCNTs enhances the nonlinear conductivity of MWCNTs-WS2/EPDM composites obviously at 25℃, and the improvement is regularly by increasing the content of MWCNTs. Because of the excellent conductivity of MWCNTs and the electrical conduction positive temperature coefficient effect of itself, the nonlinear conductivity of MWCNTs-WS2/EPDM composites decreases with the increasing of temperature. There is no nonlinear change for the conductivity of MWCNTs-WS2/EPDM composites in increasing electric field at 80℃.The thermal conductivity of MWCNTs-WS2/EPDM composites is improved obviously with the help of MWCNTs.
Small amount of multi-walled carbon nanotubes (MWCNTs) was mixed with certain content of WS2 to fabricate a composite filler, then mixing which with ethylene propylene diene monomer (EPDM) to get the MWCNTs-WS2/EPDM composites with different MWCNTs content. The composite samples were prepared by using a mixing process and the nonlinear conductivity, direct current dielectric breakdown strength and thermal conductivity of MWCNTs-WS2/EPDM composites were investigated. The results show that with the help of WS2, very small amount of MWCNTs enhances the nonlinear conductivity of MWCNTs-WS2/EPDM composites obviously at 25℃, and the improvement is regularly by increasing the content of MWCNTs. Because of the excellent conductivity of MWCNTs and the electrical conduction positive temperature coefficient effect of itself, the nonlinear conductivity of MWCNTs-WS2/EPDM composites decreases with the increasing of temperature. There is no nonlinear change for the conductivity of MWCNTs-WS2/EPDM composites in increasing electric field at 80℃.The thermal conductivity of MWCNTs-WS2/EPDM composites is improved obviously with the help of MWCNTs.
2019, 36(3): 756-763.
doi: 10.13801/j.cnki.fhclxb.20180615.001
Abstract:
BiVO4/BaTiO3 composites were prepared by mixing-calcining treatment of BaTiO3 and BiVO4 nanoparticles. XRD and FTIR analysis indicate that the BiVO4/BaTiO3 composite is consisted of BiVO4 and BaTiO3, and no trace of impurity phase is detected. TEM observation exhibits that the BaTiO3 nanoparticles with~55 nm are decorated on the surface of BiVO4 particles with an average size of~400 nm. The photocatalytic activity of BiVO4/BaTiO3 composites was evaluated by the degradation of acid orange 7(AO7) under simulated sunlight irradiation, revealing that the BiVO4/BaTiO3 composites exhibit improved photocatalytic activity compared to bare BaTiO3. The photocatalytic activity of BiVO4/BaTiO3 composite achieves the optical value when the content of BiVO4 reaches 8wt% and about 68% of dye is degraded after 6 h exposure, which is 1.9 times of bare BaTiO3. Moreover, the BiVO4/BaTiO3 composite has good photocatalytic stability and the degradation percentage of AO7 maintains~62% for three consecutive runs. The analysis of the photocatalytic mechanism suggests that the enhancement of the photocatalytic activity for the BiVO4/BaTiO3 composite is attributed to the photogenerated electron-hole pairs separation derived from the charge migration between BiVO4 and BaTiO3.
BiVO4/BaTiO3 composites were prepared by mixing-calcining treatment of BaTiO3 and BiVO4 nanoparticles. XRD and FTIR analysis indicate that the BiVO4/BaTiO3 composite is consisted of BiVO4 and BaTiO3, and no trace of impurity phase is detected. TEM observation exhibits that the BaTiO3 nanoparticles with~55 nm are decorated on the surface of BiVO4 particles with an average size of~400 nm. The photocatalytic activity of BiVO4/BaTiO3 composites was evaluated by the degradation of acid orange 7(AO7) under simulated sunlight irradiation, revealing that the BiVO4/BaTiO3 composites exhibit improved photocatalytic activity compared to bare BaTiO3. The photocatalytic activity of BiVO4/BaTiO3 composite achieves the optical value when the content of BiVO4 reaches 8wt% and about 68% of dye is degraded after 6 h exposure, which is 1.9 times of bare BaTiO3. Moreover, the BiVO4/BaTiO3 composite has good photocatalytic stability and the degradation percentage of AO7 maintains~62% for three consecutive runs. The analysis of the photocatalytic mechanism suggests that the enhancement of the photocatalytic activity for the BiVO4/BaTiO3 composite is attributed to the photogenerated electron-hole pairs separation derived from the charge migration between BiVO4 and BaTiO3.
2019, 36(3): 764-769.
doi: 10.13801/j.cnki.fhclxb.20180712.001
Abstract:
MnO2 has been used as a capacitor material owing to its high theoretical specific capacitance, however, its poor conductivity and cycle stability limits its electrochemical applications. The annealed ultrathin MnOx-modified porous carbon nanofiber (APCNF-MnOx) was successfully fabricated by self-incubation of electrospun porous carbon nanofibers (PCNF) in KMnO4 solution and followed by heat treatment. The effects of porosity of the carbon fiber on the morphology of MnOx and the electrochemical properties were comparatively studied by contact angle test, SEM, TEM and electrochemical characterization. The electrochemical results demonstrate that the APCNF-MnOx electrode can keep high capacitance retention, with the specific capacity 4 times higher (20 mV/s) than that of the annealed MnOx-modified nonporous carbon nanofiber (ACNF-MnOx). The APCNF-MnOx, as a cathode, is applied successfully for capacitive desalination. The desalination amount of the capacitor reaches 9.23 mg/g, which is 29% higher than that of ACNF-MnOx.
MnO2 has been used as a capacitor material owing to its high theoretical specific capacitance, however, its poor conductivity and cycle stability limits its electrochemical applications. The annealed ultrathin MnOx-modified porous carbon nanofiber (APCNF-MnOx) was successfully fabricated by self-incubation of electrospun porous carbon nanofibers (PCNF) in KMnO4 solution and followed by heat treatment. The effects of porosity of the carbon fiber on the morphology of MnOx and the electrochemical properties were comparatively studied by contact angle test, SEM, TEM and electrochemical characterization. The electrochemical results demonstrate that the APCNF-MnOx electrode can keep high capacitance retention, with the specific capacity 4 times higher (20 mV/s) than that of the annealed MnOx-modified nonporous carbon nanofiber (ACNF-MnOx). The APCNF-MnOx, as a cathode, is applied successfully for capacitive desalination. The desalination amount of the capacitor reaches 9.23 mg/g, which is 29% higher than that of ACNF-MnOx.
