2019 Vol. 36, No. 7
2019, 36(7): 1575-1582.
doi: 10.13801/j.cnki.fhclxb.20181009.004
Abstract:
In order to improve the thermal properties and impact rupture strength, flexural strength and hardness et al mechanical properties of polyimide (PI), two-dimensional layered structure nanomaterial Ti3C2Tx was prepared by liquid-phase etching of a ternary layered ceramic Ti3AlC2. The crystal structure and morphology of as-prepared were characterized by XRD and FESEM. The Ti3C2Tx/PI composites with different concentrations of Ti3C2Tx were prepared by wet ball milling and hot pressing. The effects of Ti3C2Tx on the thermal properties, impact rupture strength, flexural strength and hardness of Ti3C2Tx/PI composites were investigated. Simultaneously, the fracture morphology was analyzed. The results suggest that Ti3C2Tx with a thickness of 20-50 nm is nanosheets layered structure, which can uniformly disperse in the PI matrix. During the curing process, PI enters the Ti3C2Tx layers and improves the bonding force between PI and Ti3C2Tx, resulting in good combining interface. The addition of Ti3C2Tx nanosheets enhance the glass transition temperature of PI and improve the impact rupture strength, flexural strength, and hardness properties of the matrix. When adding amount of Ti3C2Tx is 0.25wt%, the glass transition temperature of Ti3C2Tx/PI composite increases by 17℃ and the impact rupture strength ascends by 31%.
In order to improve the thermal properties and impact rupture strength, flexural strength and hardness et al mechanical properties of polyimide (PI), two-dimensional layered structure nanomaterial Ti3C2Tx was prepared by liquid-phase etching of a ternary layered ceramic Ti3AlC2. The crystal structure and morphology of as-prepared were characterized by XRD and FESEM. The Ti3C2Tx/PI composites with different concentrations of Ti3C2Tx were prepared by wet ball milling and hot pressing. The effects of Ti3C2Tx on the thermal properties, impact rupture strength, flexural strength and hardness of Ti3C2Tx/PI composites were investigated. Simultaneously, the fracture morphology was analyzed. The results suggest that Ti3C2Tx with a thickness of 20-50 nm is nanosheets layered structure, which can uniformly disperse in the PI matrix. During the curing process, PI enters the Ti3C2Tx layers and improves the bonding force between PI and Ti3C2Tx, resulting in good combining interface. The addition of Ti3C2Tx nanosheets enhance the glass transition temperature of PI and improve the impact rupture strength, flexural strength, and hardness properties of the matrix. When adding amount of Ti3C2Tx is 0.25wt%, the glass transition temperature of Ti3C2Tx/PI composite increases by 17℃ and the impact rupture strength ascends by 31%.
2019, 36(7): 1583-1590.
doi: 10.13801/j.cnki.fhclxb.20181121.001
Abstract:
The cellulose nanofiber-reduced graphene oxide (CNF-rGO) composite hydrogel was prepared by ascorbic acid reduction of CNF-graphene oxide (GO) composite hydrogel which was obtained from CNF with high aspect ratio and GO with nanosheet. By freeze-drying method, CNF-rGO composite aerogel was obtained. By the in situ polymerization of aniline monomer, CNF-rGO/polyaniline (PANI) composite aerogels as flexible electrode materials was prepared. The effects of different dosage mass ratio of aniline, CNF and rGO on the morphology, structure and electrochemical properties of CNF-rGO/PANI aerogels electrode composites were studied. The results show that the CNF-rGO/PANI composite aerogels still have relatively close 3D network structure after in situ polymerization of aniline. Compared with rGO/PANI aerogel eletrode composites, the CNF-rGO/PANI aerogel eletrode composites have more excellent capacitance behavior. When the mass ratio of CNF and GO is 60:40 and the amount of PANI is 0.1 mol, the specific capacitance of the CNF-rGO/PANI aerogel electrode composites is 85.9 Fg-1, and its electrochemical properties are hardly affected by bending degree. So, the CNF-rGO/PANI aerogel eletrode composites show good electrochemical performance and excellent flexibility.
The cellulose nanofiber-reduced graphene oxide (CNF-rGO) composite hydrogel was prepared by ascorbic acid reduction of CNF-graphene oxide (GO) composite hydrogel which was obtained from CNF with high aspect ratio and GO with nanosheet. By freeze-drying method, CNF-rGO composite aerogel was obtained. By the in situ polymerization of aniline monomer, CNF-rGO/polyaniline (PANI) composite aerogels as flexible electrode materials was prepared. The effects of different dosage mass ratio of aniline, CNF and rGO on the morphology, structure and electrochemical properties of CNF-rGO/PANI aerogels electrode composites were studied. The results show that the CNF-rGO/PANI composite aerogels still have relatively close 3D network structure after in situ polymerization of aniline. Compared with rGO/PANI aerogel eletrode composites, the CNF-rGO/PANI aerogel eletrode composites have more excellent capacitance behavior. When the mass ratio of CNF and GO is 60:40 and the amount of PANI is 0.1 mol, the specific capacitance of the CNF-rGO/PANI aerogel electrode composites is 85.9 Fg-1, and its electrochemical properties are hardly affected by bending degree. So, the CNF-rGO/PANI aerogel eletrode composites show good electrochemical performance and excellent flexibility.
2019, 36(7): 1591-1600.
doi: 10.13801/j.cnki.fhclxb.20181017.001
Abstract:
Poly(furfuryl alcohol) (PFA) was synthesized by the hydrothermal method. The effect of surfactant polyvinylpyrrolidone (PVP) amount and hydrothermal duration on the micromorphology of PFA was investigated. PFA and Ni foam were coated with graphene oxide (GO) prepared by the modified Hummers method, and the coating effects of different mass ratios of PFA:GO were investigated. 3D macroporous graphene (3D rGO) was successfully built through removing PFA and Ni foam templates. 3D hierarchical porous graphene (3D PrGO) was constructed on 3D rGO by KOH activation. 3D PrGO/PANI was synthesized by in-situ composite. The phase composition, microstructure and morphology were analyzed by XRD, SEM, TEM, FTIR, XPS and Brunner-Emmet-Teller (BET) measurements. The electrochemical performance of the composites was analyzed by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The results show that PFA microspheres with a diameter of about 500 nm are successfully synthesized by controlling the ratio of furfuryl alcohol, PVP and water at 180℃ for 24 h. The coating effect is the best at mass ratio of PFA:GO=1:1. The PFA templates are successfully removed by heat treatment at 450℃ for 6 h and pore sizes of 400-600 nm are formed. The mesopores are formed on the 3D rGO after KOH activation. The specific capacitance of 3D PrGO/PANI composites is 433 F/g at 0.5 A/g, and retains 75% after 1 000 cycling at 1 A/g, which is higher than that of pure PANI (69%).
Poly(furfuryl alcohol) (PFA) was synthesized by the hydrothermal method. The effect of surfactant polyvinylpyrrolidone (PVP) amount and hydrothermal duration on the micromorphology of PFA was investigated. PFA and Ni foam were coated with graphene oxide (GO) prepared by the modified Hummers method, and the coating effects of different mass ratios of PFA:GO were investigated. 3D macroporous graphene (3D rGO) was successfully built through removing PFA and Ni foam templates. 3D hierarchical porous graphene (3D PrGO) was constructed on 3D rGO by KOH activation. 3D PrGO/PANI was synthesized by in-situ composite. The phase composition, microstructure and morphology were analyzed by XRD, SEM, TEM, FTIR, XPS and Brunner-Emmet-Teller (BET) measurements. The electrochemical performance of the composites was analyzed by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The results show that PFA microspheres with a diameter of about 500 nm are successfully synthesized by controlling the ratio of furfuryl alcohol, PVP and water at 180℃ for 24 h. The coating effect is the best at mass ratio of PFA:GO=1:1. The PFA templates are successfully removed by heat treatment at 450℃ for 6 h and pore sizes of 400-600 nm are formed. The mesopores are formed on the 3D rGO after KOH activation. The specific capacitance of 3D PrGO/PANI composites is 433 F/g at 0.5 A/g, and retains 75% after 1 000 cycling at 1 A/g, which is higher than that of pure PANI (69%).
2019, 36(7): 1601-1606.
doi: 10.13801/j.cnki.fhclxb.20181108.005
Abstract:
The silk graft polyacrylonitrile-polyacrylamide (SF-g-P(AN-co-AM)) composite filtration membrane was produced using zinc chloride aqueous solution as the solvent and using water as the coagulation bath. The SF-g-P(AN-co-AM) composite filtration membrane was characterized by SEM, TG analysis and water contact angle. The mechanical properties, separation performance and anti-fouling performance of the SF-g-P(AN-co-AM) membrane were tested. The results show that the fracture strength of the SF-g-P(AN-co-AM) membrane increases with the increasing of the acrylamide content, but the flux decreaseds. When 0.5 g of acrylamide is used, the fracture strength of the SF-g-P(AN-co-AM) membrane reaches 1.4 MPa. The SF-g-P(AN-co-AM) membrane has good separation performance, when the water flux is 35 L/(m2h) under 0.1 MPa pressure and the rejection rate of 0.03 g/L Congo red (Mw=696.68) solution reaches 99%. The SF-g-P(AN-co-AM) membrane exhibits good anti-fouling performance, and the flux recovery rate is 94.4% after three cycles of pure water and bovine serum albumin solution filtration without cleaning.
The silk graft polyacrylonitrile-polyacrylamide (SF-g-P(AN-co-AM)) composite filtration membrane was produced using zinc chloride aqueous solution as the solvent and using water as the coagulation bath. The SF-g-P(AN-co-AM) composite filtration membrane was characterized by SEM, TG analysis and water contact angle. The mechanical properties, separation performance and anti-fouling performance of the SF-g-P(AN-co-AM) membrane were tested. The results show that the fracture strength of the SF-g-P(AN-co-AM) membrane increases with the increasing of the acrylamide content, but the flux decreaseds. When 0.5 g of acrylamide is used, the fracture strength of the SF-g-P(AN-co-AM) membrane reaches 1.4 MPa. The SF-g-P(AN-co-AM) membrane has good separation performance, when the water flux is 35 L/(m2h) under 0.1 MPa pressure and the rejection rate of 0.03 g/L Congo red (Mw=696.68) solution reaches 99%. The SF-g-P(AN-co-AM) membrane exhibits good anti-fouling performance, and the flux recovery rate is 94.4% after three cycles of pure water and bovine serum albumin solution filtration without cleaning.
2019, 36(7): 1607-1617.
doi: 10.13801/j.cnki.fhclxb.20180919.002
Abstract:
Different mass ratios of graphene nanoplates (Gnps) were added into Zn/epoxy (EP) coatings with 40%Zn content to prepare Gnps-40%Zn/EP composite coatings. The Zn/EP coating with 70%Zn content was also prepared as the contrast. The Raman spectra, SEM, salt spray test and electrochemical technique et al were applied to evaluate the barrier property and cathodic protection effect of Gnps-40%Zn/EP composite coatings. The anticorrosive effects of Gnps-40%Zn/EP composite coatings and 70%Zn/EP coating were compared to explore the possibility of reducing Zn content by adding Gnps into Zn/EP coating. To further clarify anticorrosive mechanism of Zn/EP coating with varying Gnps addition, the anticorrosive model was established. The results indicate that Gnps could be well-dispersed into Zn/EP coatings, but disorder parameter of Gnps increases with the increasing of Gnps addition. While Gnps addition are 0.3%, 0.5% and 1.0%, the physical shielding performance of Zn/EP coating can be significantly improved; while Gnps addition are 0.5% and 1.0%, the cathodic protection effect of Zn/EP coatings can be significantly enhanced; While Gnps addition is 1.5%, both shielding performance and cathodic protection effect of Zn/EP coatings are not obviously improved. For Gnps-40%Zn/EP composite coating, the best addition range of Gnps is 0.5%-1.0%. The suitable addition of Gnps can reduce Zn content in Zn/EP coating and lower the production cost.
Different mass ratios of graphene nanoplates (Gnps) were added into Zn/epoxy (EP) coatings with 40%Zn content to prepare Gnps-40%Zn/EP composite coatings. The Zn/EP coating with 70%Zn content was also prepared as the contrast. The Raman spectra, SEM, salt spray test and electrochemical technique et al were applied to evaluate the barrier property and cathodic protection effect of Gnps-40%Zn/EP composite coatings. The anticorrosive effects of Gnps-40%Zn/EP composite coatings and 70%Zn/EP coating were compared to explore the possibility of reducing Zn content by adding Gnps into Zn/EP coating. To further clarify anticorrosive mechanism of Zn/EP coating with varying Gnps addition, the anticorrosive model was established. The results indicate that Gnps could be well-dispersed into Zn/EP coatings, but disorder parameter of Gnps increases with the increasing of Gnps addition. While Gnps addition are 0.3%, 0.5% and 1.0%, the physical shielding performance of Zn/EP coating can be significantly improved; while Gnps addition are 0.5% and 1.0%, the cathodic protection effect of Zn/EP coatings can be significantly enhanced; While Gnps addition is 1.5%, both shielding performance and cathodic protection effect of Zn/EP coatings are not obviously improved. For Gnps-40%Zn/EP composite coating, the best addition range of Gnps is 0.5%-1.0%. The suitable addition of Gnps can reduce Zn content in Zn/EP coating and lower the production cost.
Effects of adding (H4N)2S on corrosion performance of electro synthesized CoO/PANI composite coating
2019, 36(7): 1618-1624.
doi: 10.13801/j.cnki.fhclxb.20181107.002
Abstract:
The CoO/polyaniline (PANI) composite coatings were synthesized in the electrolyte of CoSO4-C6H7N-H2SO4 mixture by means of constant potential method. The effect of (H4N)2S on the CoO/PANI composite coating was studied, and corrosion resistance and microstructure of the CoO/PANI composite coatings were analyzed by combining electrochemical testing technology, SEM, XRD and accelerated corrosion tests. The results show that the CoO exists in the form of crystal in the CoO/PANI composite coatings. With the loading of (H4N)2S, the microstructure of the CoO/PANI coatings changes from irregular thin lamellar morphology into uniform dense contiguous lamellar morphology, when more (H4N)2S was added, a small amount of holes appear on the surface of the (H4N)2S-CoO/PANI composite coating. Self-corrosion current density of CoO/PANI composite film without (H4N)2S is 7.079×10-6 A/cm2, and self-corrosion potential is -0.545 V. After 0.3 g/L (H4N)2S is added, self-corrosion current density of the (H4N)2S-CoO/PANI composite coating is 7.943×10-7 A/cm2, corrosion potential is -0.314 V, polarization resistance is 6 426.8 Ωcm2, corrosion time of 10% HCl drip reaches 478 s, and no rust is observed after 56 h of neutral salt spray test. Addition of (H4N)2S has obvious effects on corrosion resistance of the (H4N)2S-CoO/PANI composite coatings.
The CoO/polyaniline (PANI) composite coatings were synthesized in the electrolyte of CoSO4-C6H7N-H2SO4 mixture by means of constant potential method. The effect of (H4N)2S on the CoO/PANI composite coating was studied, and corrosion resistance and microstructure of the CoO/PANI composite coatings were analyzed by combining electrochemical testing technology, SEM, XRD and accelerated corrosion tests. The results show that the CoO exists in the form of crystal in the CoO/PANI composite coatings. With the loading of (H4N)2S, the microstructure of the CoO/PANI coatings changes from irregular thin lamellar morphology into uniform dense contiguous lamellar morphology, when more (H4N)2S was added, a small amount of holes appear on the surface of the (H4N)2S-CoO/PANI composite coating. Self-corrosion current density of CoO/PANI composite film without (H4N)2S is 7.079×10-6 A/cm2, and self-corrosion potential is -0.545 V. After 0.3 g/L (H4N)2S is added, self-corrosion current density of the (H4N)2S-CoO/PANI composite coating is 7.943×10-7 A/cm2, corrosion potential is -0.314 V, polarization resistance is 6 426.8 Ωcm2, corrosion time of 10% HCl drip reaches 478 s, and no rust is observed after 56 h of neutral salt spray test. Addition of (H4N)2S has obvious effects on corrosion resistance of the (H4N)2S-CoO/PANI composite coatings.
2019, 36(7): 1625-1632.
doi: 10.13801/j.cnki.fhclxb.20181023.001
Abstract:
In order to investigate the seawater corrosion resistance of high-density polyethylene (HDPE) based wood plastic composites, four types of plant fibers (eucalyptus, poplar, bamboo, and rice husk fibers) were incorporated into HDPE. The simulated accelerated seawater corrosion test was carried on to analysis the mechanical properties, color stability, microstructure and chemical groups of four types of plant fibers/HDPE composites before and after corrosion. The results show that the accelerated seawater corrosion would result in poorer fiber/matrix bonding quality (increasing cracks and holes), mechanical properties and color stability (the color shifts towards white, yellow and green for eucalyptus/HDPE and poplar/HDPE and rice husk/HDPE composites, and the color shifts towards white, blue and green for bamboo/HDPE composites), and higher hydroxyl content. After 21 days seawater corrosion, the reductions of the flexural strength and modulus of eucalyptus/HDPE composites are 12.94% and 23.18%, respectively; for the bamboo/HDPE composites, the reductions are 15.45% and 23.20%, respectively; for the rice husk/HDPE composites, the reductions are 18.53% and 25.15%, respectively; and for the poplar/HDPE composites, the reductions are 18.52% and 34.21%, respectively. The eucalyptus/HDPE and poplar/HDPE composites present the lowest and highest degradation (such as mechanical loss, color fading and interfacial debonding) after corrosion, respectively.
In order to investigate the seawater corrosion resistance of high-density polyethylene (HDPE) based wood plastic composites, four types of plant fibers (eucalyptus, poplar, bamboo, and rice husk fibers) were incorporated into HDPE. The simulated accelerated seawater corrosion test was carried on to analysis the mechanical properties, color stability, microstructure and chemical groups of four types of plant fibers/HDPE composites before and after corrosion. The results show that the accelerated seawater corrosion would result in poorer fiber/matrix bonding quality (increasing cracks and holes), mechanical properties and color stability (the color shifts towards white, yellow and green for eucalyptus/HDPE and poplar/HDPE and rice husk/HDPE composites, and the color shifts towards white, blue and green for bamboo/HDPE composites), and higher hydroxyl content. After 21 days seawater corrosion, the reductions of the flexural strength and modulus of eucalyptus/HDPE composites are 12.94% and 23.18%, respectively; for the bamboo/HDPE composites, the reductions are 15.45% and 23.20%, respectively; for the rice husk/HDPE composites, the reductions are 18.53% and 25.15%, respectively; and for the poplar/HDPE composites, the reductions are 18.52% and 34.21%, respectively. The eucalyptus/HDPE and poplar/HDPE composites present the lowest and highest degradation (such as mechanical loss, color fading and interfacial debonding) after corrosion, respectively.
2019, 36(7): 1633-1639.
doi: 10.13801/j.cnki.fhclxb.20181009.003
Abstract:
In order to improve the friction and wear properties of epoxy resin (EP) matrix composites and prepare low-cost EP wear resistant materials, nano SiO2 particles and bamboo fibers (BF) were used as fillers to prepare nano SiO2-BF/EP composites. The friction and wear tester, dynamic thermomechanical analyzer and SEM were used to study the effect of nanoparticles and fibers on the wear resistance, thermodynamic properties and microstructure of the composites. The results show that after adding BF alone, the volumetric wear of BF/EP composite is significantly reduced by 71% compared with the pure EP under the same conditions; At the same time, the addition of nano SiO2 and BF has a significant effect on the glass transition temperature and wear volume of nano SiO2-BF/EP composite. The glass transition temperature is 11℃ higher than that of the pure EP, reaching 124℃. The volumetric wear is about 75.3% lower than that of the pure EP under the same conditions.
In order to improve the friction and wear properties of epoxy resin (EP) matrix composites and prepare low-cost EP wear resistant materials, nano SiO2 particles and bamboo fibers (BF) were used as fillers to prepare nano SiO2-BF/EP composites. The friction and wear tester, dynamic thermomechanical analyzer and SEM were used to study the effect of nanoparticles and fibers on the wear resistance, thermodynamic properties and microstructure of the composites. The results show that after adding BF alone, the volumetric wear of BF/EP composite is significantly reduced by 71% compared with the pure EP under the same conditions; At the same time, the addition of nano SiO2 and BF has a significant effect on the glass transition temperature and wear volume of nano SiO2-BF/EP composite. The glass transition temperature is 11℃ higher than that of the pure EP, reaching 124℃. The volumetric wear is about 75.3% lower than that of the pure EP under the same conditions.
2019, 36(7): 1640-1649.
doi: 10.13801/j.cnki.fhclxb.20181108.002
Abstract:
The curing process and curing kinetics of bismaleimide-polyethersulfone (BMI-PES) multi-phase systems were investigated by DSC using the non-isothermal method at different heating rates. The apparent activation energy and the pre-exponential factor of the curing BMI-PES resin systems were calculated by Kissinger method, and the reaction series were computed by means of Crane formula, and the kinetic equation was concluded. The curing reaction kinetics formula of BMI-PES resin was presented and validated with the homologous experiment. The microphase structure evolution of the curing BMI-PES resin systems with the curing temperature as well as curing time was investigated by SEM. The results indicate that autocatalytic phenomenon exists in the curing reaction process of BMI-PES system and PES resin participates in the curing process of BMI resin. With the increasing of the heating rate of BMI-PES, the curing characteristic temperatures of BMI-PES systems shift toward higher temperature values while the curing enthalpy values are almost constant. With the increasing of the PES content, the curing rate increases accordingly, while the enthalpy decreases, and the curing peak temperature is almost constant. Based on the curing kinetics study, the apparent activation energy of BMI-PES curing reaction increases while the pre-exponential factor and the reaction series are not changed. The curing process of the curing reactions follows the first order reaction. The experimental cure degree is fitted highly well with the theoretical one in the initiation of curing reaction at 200℃. The SEM results suggest that phase inversion structure exists in BMI-PES resin system after 180℃.
The curing process and curing kinetics of bismaleimide-polyethersulfone (BMI-PES) multi-phase systems were investigated by DSC using the non-isothermal method at different heating rates. The apparent activation energy and the pre-exponential factor of the curing BMI-PES resin systems were calculated by Kissinger method, and the reaction series were computed by means of Crane formula, and the kinetic equation was concluded. The curing reaction kinetics formula of BMI-PES resin was presented and validated with the homologous experiment. The microphase structure evolution of the curing BMI-PES resin systems with the curing temperature as well as curing time was investigated by SEM. The results indicate that autocatalytic phenomenon exists in the curing reaction process of BMI-PES system and PES resin participates in the curing process of BMI resin. With the increasing of the heating rate of BMI-PES, the curing characteristic temperatures of BMI-PES systems shift toward higher temperature values while the curing enthalpy values are almost constant. With the increasing of the PES content, the curing rate increases accordingly, while the enthalpy decreases, and the curing peak temperature is almost constant. Based on the curing kinetics study, the apparent activation energy of BMI-PES curing reaction increases while the pre-exponential factor and the reaction series are not changed. The curing process of the curing reactions follows the first order reaction. The experimental cure degree is fitted highly well with the theoretical one in the initiation of curing reaction at 200℃. The SEM results suggest that phase inversion structure exists in BMI-PES resin system after 180℃.
2019, 36(7): 1650-1657.
doi: 10.13801/j.cnki.fhclxb.20180930.003
Abstract:
Organic modified montmorillonite (OMMT) was prepared by intercalation modification of montmorillonite with Gemini surfactant. The OMMT/polystyrene (PS) composites were fabricated through solution mixing. The OMMT/PS composites and polyethylene (PE) were melt-blended to obtain OMMT/PS-PE composites. The effect of OMMT on the mechanical properties and phase morphology of OMMT/PS-PE composite was analyzed. The characterizations of OMMT by FTIR, XRD and TG show that Gemini surfactant is successfully intercalated into the layer of montmorillonite. The morphological structure of OMMT/PS-PE composites and the changes of the particle size of PS dispersed phase, as well as the relationship between the phase morphology and the mechanical properties were examined by SEM observation and electronic universal testing machine. The results demonstrate that the particle size of the disperse phase gradually decreases with the addition of OMMT. The phase morphology of the OMMT/PS-PE composites changes from "sea-island" to co-continuous structure when the content of OMMT reaches to 2.5wt%. Compared with PE-PS matrix without OMMT, the flexural modulus and elongation at break of OMMT/PS-PE composites are significantly improved, and increases more than about 18% and 50 times, respectively.
Organic modified montmorillonite (OMMT) was prepared by intercalation modification of montmorillonite with Gemini surfactant. The OMMT/polystyrene (PS) composites were fabricated through solution mixing. The OMMT/PS composites and polyethylene (PE) were melt-blended to obtain OMMT/PS-PE composites. The effect of OMMT on the mechanical properties and phase morphology of OMMT/PS-PE composite was analyzed. The characterizations of OMMT by FTIR, XRD and TG show that Gemini surfactant is successfully intercalated into the layer of montmorillonite. The morphological structure of OMMT/PS-PE composites and the changes of the particle size of PS dispersed phase, as well as the relationship between the phase morphology and the mechanical properties were examined by SEM observation and electronic universal testing machine. The results demonstrate that the particle size of the disperse phase gradually decreases with the addition of OMMT. The phase morphology of the OMMT/PS-PE composites changes from "sea-island" to co-continuous structure when the content of OMMT reaches to 2.5wt%. Compared with PE-PS matrix without OMMT, the flexural modulus and elongation at break of OMMT/PS-PE composites are significantly improved, and increases more than about 18% and 50 times, respectively.
2019, 36(7): 1658-1666.
doi: 10.13801/j.cnki.fhclxb.20181108.004
Abstract:
With 4,4'-diamino diphenyl methane (DDM) as the curing agent, bismaleimide (BMI) and phenolic epoxy resin (F51) as the matrix, polyethersulfone (PES) as the toughening agent and functionalized nano SiO2 by silane coupling agent KH560(KH-SiO2) as the modifier, the KH-SiO2-PES/BMI-F51 composites were prepared by in-situ polymerization method, and the curing process and reaction curing kinetics were determined by non-isothermal DSC. The apparent activation energy of KH-SiO2-PES/BMI-F51 composites are 96.03 kJ/mol and 99.18 kJ/mol according to Kissinger equation and Ozawa equation, respectively. The FTIR results reveal that the surface modification of KH-SiO2 is favourable, the characteristic peaks of unsaturated double bond and epoxy group disappear, and the C=C double bond in BMI and epoxy group in F51 are involved in the curing reaction of KH-SiO2-PES/BMI-F51 composites under the effect of DDM. The SEM images exhibit that PES resin and KH-SiO2 uniformly disperse in the resin matrix when the content of PES resin and KH-SiO2 are appropriate, the broken cracks develop irregularly and the material exhibits ductile fracture. The mechanical performances and thermogravimetric properties show that bending strength, bending modulus and impact strength of KH-SiO2-PES/BMI-F51composites are 156.23 MPa, 4.18 GPa and 20.89 kJ/m2, when the mass fraction of PES and KH-SiO2 are 4wt% and 1.5wt%, which are 49.7%, 29.4% and 82.8% higher than that of BMI-F51 matrix, respectively. The thermal decomposition temperature of KH-SiO2-PES/BMI-F51 composites is 393.1℃, and the temperature at the residual mass of 50% reaches 523.1℃, the heat-resistant property is excellent. The mechanical properties and heat-resistant properties of KH-SiO2-PES/BMI-F51 composites are greatly improved, which provides theoretical data for expanding the application range of F51 and BMI.
With 4,4'-diamino diphenyl methane (DDM) as the curing agent, bismaleimide (BMI) and phenolic epoxy resin (F51) as the matrix, polyethersulfone (PES) as the toughening agent and functionalized nano SiO2 by silane coupling agent KH560(KH-SiO2) as the modifier, the KH-SiO2-PES/BMI-F51 composites were prepared by in-situ polymerization method, and the curing process and reaction curing kinetics were determined by non-isothermal DSC. The apparent activation energy of KH-SiO2-PES/BMI-F51 composites are 96.03 kJ/mol and 99.18 kJ/mol according to Kissinger equation and Ozawa equation, respectively. The FTIR results reveal that the surface modification of KH-SiO2 is favourable, the characteristic peaks of unsaturated double bond and epoxy group disappear, and the C=C double bond in BMI and epoxy group in F51 are involved in the curing reaction of KH-SiO2-PES/BMI-F51 composites under the effect of DDM. The SEM images exhibit that PES resin and KH-SiO2 uniformly disperse in the resin matrix when the content of PES resin and KH-SiO2 are appropriate, the broken cracks develop irregularly and the material exhibits ductile fracture. The mechanical performances and thermogravimetric properties show that bending strength, bending modulus and impact strength of KH-SiO2-PES/BMI-F51composites are 156.23 MPa, 4.18 GPa and 20.89 kJ/m2, when the mass fraction of PES and KH-SiO2 are 4wt% and 1.5wt%, which are 49.7%, 29.4% and 82.8% higher than that of BMI-F51 matrix, respectively. The thermal decomposition temperature of KH-SiO2-PES/BMI-F51 composites is 393.1℃, and the temperature at the residual mass of 50% reaches 523.1℃, the heat-resistant property is excellent. The mechanical properties and heat-resistant properties of KH-SiO2-PES/BMI-F51 composites are greatly improved, which provides theoretical data for expanding the application range of F51 and BMI.
2019, 36(7): 1667-1673.
doi: 10.13801/j.cnki.fhclxb.20181122.003
Abstract:
Zn doped β-tricalcium phosphate (β-TCP) powder was prepared by the chemical coprecipitation, mixed with Ti powder at 3:7 (mass ratio) and pressed evenly, and Zn doped β-TCP/Ti composite samples were obtained by vacuum sintering. The microstructure, surface morphology and phase analysis were carried out by metallographic observation, SEM and XRD, and microhardness, abrasive wear, uniaxial compression and in vitro bioactivity tests were carried out. The results show that the particle size (D50) in Zn-β-TCP powder is focus on 1-20 μm. The component of Zn-β-TCP/Ti composite are TiO2, β-TCP and CaTiO3. The phases of Zn-β-TCP/Ti composites consist of TiO2, β-TCP, CaTiO3 and ZnO. When Zn2+ is dissolved into β-TCP lattice, the diffraction peak is shifted, and the Zn-β-TCP/Ti biocomposite with 10mol% Zn has the largest migration angle. The crystallinity of β-TCP decreases with the increase of Zn. The TiO2 phase of the β-TCP/Ti composite is dispersed in the net β-TCP phase. The pore size of the Zn-β-TCP/Ti composite with 10mol% Zn is 200-300 μm, which meets the requirements of engineering scaffold materials, with the highest microhardness of HV 346.2, the lowest wear loss of 0.051 mgmm-2, the compressive strength between 130-180 MPa, and the maximum elastic modulus of 8.021 GPa. The addition of Zn improves the microhardness and wear resistance of the Zn-β-TCP/Ti composites. The accumulation of carbonate hydroxyapatite increases with the soaking in simulated body fluid, and the Zn-β-TCP/Ti biocomposites have good bioactivity.
Zn doped β-tricalcium phosphate (β-TCP) powder was prepared by the chemical coprecipitation, mixed with Ti powder at 3:7 (mass ratio) and pressed evenly, and Zn doped β-TCP/Ti composite samples were obtained by vacuum sintering. The microstructure, surface morphology and phase analysis were carried out by metallographic observation, SEM and XRD, and microhardness, abrasive wear, uniaxial compression and in vitro bioactivity tests were carried out. The results show that the particle size (D50) in Zn-β-TCP powder is focus on 1-20 μm. The component of Zn-β-TCP/Ti composite are TiO2, β-TCP and CaTiO3. The phases of Zn-β-TCP/Ti composites consist of TiO2, β-TCP, CaTiO3 and ZnO. When Zn2+ is dissolved into β-TCP lattice, the diffraction peak is shifted, and the Zn-β-TCP/Ti biocomposite with 10mol% Zn has the largest migration angle. The crystallinity of β-TCP decreases with the increase of Zn. The TiO2 phase of the β-TCP/Ti composite is dispersed in the net β-TCP phase. The pore size of the Zn-β-TCP/Ti composite with 10mol% Zn is 200-300 μm, which meets the requirements of engineering scaffold materials, with the highest microhardness of HV 346.2, the lowest wear loss of 0.051 mgmm-2, the compressive strength between 130-180 MPa, and the maximum elastic modulus of 8.021 GPa. The addition of Zn improves the microhardness and wear resistance of the Zn-β-TCP/Ti composites. The accumulation of carbonate hydroxyapatite increases with the soaking in simulated body fluid, and the Zn-β-TCP/Ti biocomposites have good bioactivity.
2019, 36(7): 1674-1683.
doi: 10.13801/j.cnki.fhclxb.20181121.002
Abstract:
The SiFe@C anode materials were prepared by mechanical ball milling and high-temperature pyrolysis method with SiFe and pitch as the raw materials, and the characteristics of a series of SiFe@C composites prepared at different pyrolysis temperatures were compared with those of uncoated SiFe. The phase composition, morphology and electrochemical performance of SiFe@C anode composites were detected by XRD, SEM, TEM, EDS and constant current charge-discharge test. The results reveal that the initial discharge specific capacity of SiFe@C composite electrode prepared at 850℃ is 1 376.25 mAh/g with the initial coulombic efficiency of 86.35%. After 70 cycles, the discharge specific capacity is 940.33 mAh/g, the coulombic efficiency is 98.78% and the capacity retention rate is 76.32%, which indicates that its cycling stability and rate capability is much higher than the SiFe and other SiFe@C electrode composites obtained at other temperatures.
The SiFe@C anode materials were prepared by mechanical ball milling and high-temperature pyrolysis method with SiFe and pitch as the raw materials, and the characteristics of a series of SiFe@C composites prepared at different pyrolysis temperatures were compared with those of uncoated SiFe. The phase composition, morphology and electrochemical performance of SiFe@C anode composites were detected by XRD, SEM, TEM, EDS and constant current charge-discharge test. The results reveal that the initial discharge specific capacity of SiFe@C composite electrode prepared at 850℃ is 1 376.25 mAh/g with the initial coulombic efficiency of 86.35%. After 70 cycles, the discharge specific capacity is 940.33 mAh/g, the coulombic efficiency is 98.78% and the capacity retention rate is 76.32%, which indicates that its cycling stability and rate capability is much higher than the SiFe and other SiFe@C electrode composites obtained at other temperatures.
2019, 36(7): 1684-1690.
doi: 10.13801/j.cnki.fhclxb.20181011.001
Abstract:
The 3wt%TiB2/Cu composites reinforced with different sized TiB2 particles were prepared by spark plasma sintering (SPS). The variations of density, electrical conductivity, hardness and arc resistance of 3wt%TiB2/Cu composites with the TiB2 particle size were studied, and arc erosion behavior of the TiB2/Cu composites reinforced with different sized TiB2 particles were emphatically analyzed. The results show that the hardness and density of 3wt%TiB2/Cu composite decrease gently with increasing of TiB2 particles size. The comprehensive performance of 3wt%TiB2/Cu composite with fine TiB2 particle size is better. With the increase of TiB2 particles size, the stability of the arc erosion resistance of 3wt%TiB2/Cu composites decreases, and the mass loss of 3wt%TiB2/Cu composites cathode material increases. The arc erosion resistance of 3wt%TiB2/Cu composite reinforced with 10 μm TiB2 particles is optimal. Observations on arc erosion morphology show that 3wt%TiB2/Cu composites are mostly transferred from cathodes to anodes, and the mass loss of cathode and arc erosion area on the contact surface increase gradually with increasing of the TiB2 particle size, which shows that the fine TiB2 particles in Cu matrix can reduce the splashing of molten copper during arc erosion.
The 3wt%TiB2/Cu composites reinforced with different sized TiB2 particles were prepared by spark plasma sintering (SPS). The variations of density, electrical conductivity, hardness and arc resistance of 3wt%TiB2/Cu composites with the TiB2 particle size were studied, and arc erosion behavior of the TiB2/Cu composites reinforced with different sized TiB2 particles were emphatically analyzed. The results show that the hardness and density of 3wt%TiB2/Cu composite decrease gently with increasing of TiB2 particles size. The comprehensive performance of 3wt%TiB2/Cu composite with fine TiB2 particle size is better. With the increase of TiB2 particles size, the stability of the arc erosion resistance of 3wt%TiB2/Cu composites decreases, and the mass loss of 3wt%TiB2/Cu composites cathode material increases. The arc erosion resistance of 3wt%TiB2/Cu composite reinforced with 10 μm TiB2 particles is optimal. Observations on arc erosion morphology show that 3wt%TiB2/Cu composites are mostly transferred from cathodes to anodes, and the mass loss of cathode and arc erosion area on the contact surface increase gradually with increasing of the TiB2 particle size, which shows that the fine TiB2 particles in Cu matrix can reduce the splashing of molten copper during arc erosion.
Preparation and ablative mechanism of C/C-ZrC-SiC composites filled with Fe-based superalloy coating
2019, 36(7): 1691-1699.
doi: 10.13801/j.cnki.fhclxb.20181112.002
Abstract:
The C/C-ZrC-SiC composites filled with Fe-based superalloy coating were prepared by low pressure suspension impregnation to improve the C/C-ZrC-SiC composites used in the field of hypersonic flight vehicle's thermal protective performance. The evolution rule of the surface microstructure of the C/C-ZrC-SiC composites filled with Fe-based superalloy before and after oxy-acetylene flame ablation was studied by means of XRD, SEM and EDS. And the effect of the Fe-based superalloy coating on the ablation behavior of the C/C-ZrC-SiC composites was clarified. The results show that the C/C-ZrC-SiC composites are infiltrated by low pressure suspension infiltration at 1 650℃ for 2 h, and a uniform, dense and tightly bonded Fe-based superalloy coating is formed on the surface. After the ablation at 2 500℃ for 180 s, the surface of the modified the C/C-ZrC-SiC composites generates a smaller ablation pit, and the mass and linear ablation rate are reduced by 8% and 35% respectively than the unmodified sample. And a uniform and dense protective layer of the Fe2O3-ZrO2 composite oxides is formed on the surface, which greatly reduces the occurrence of surface cracks, holes and other defects, thereby reducing the diffusion rate of oxygen and the stress concentration caused by defects. The Fe-based superalloy coating improves the high temperature oxidation resistance and mechanical corrosion resistance of the C/C-ZrC-SiC composites.
The C/C-ZrC-SiC composites filled with Fe-based superalloy coating were prepared by low pressure suspension impregnation to improve the C/C-ZrC-SiC composites used in the field of hypersonic flight vehicle's thermal protective performance. The evolution rule of the surface microstructure of the C/C-ZrC-SiC composites filled with Fe-based superalloy before and after oxy-acetylene flame ablation was studied by means of XRD, SEM and EDS. And the effect of the Fe-based superalloy coating on the ablation behavior of the C/C-ZrC-SiC composites was clarified. The results show that the C/C-ZrC-SiC composites are infiltrated by low pressure suspension infiltration at 1 650℃ for 2 h, and a uniform, dense and tightly bonded Fe-based superalloy coating is formed on the surface. After the ablation at 2 500℃ for 180 s, the surface of the modified the C/C-ZrC-SiC composites generates a smaller ablation pit, and the mass and linear ablation rate are reduced by 8% and 35% respectively than the unmodified sample. And a uniform and dense protective layer of the Fe2O3-ZrO2 composite oxides is formed on the surface, which greatly reduces the occurrence of surface cracks, holes and other defects, thereby reducing the diffusion rate of oxygen and the stress concentration caused by defects. The Fe-based superalloy coating improves the high temperature oxidation resistance and mechanical corrosion resistance of the C/C-ZrC-SiC composites.
2019, 36(7): 1700-1707.
doi: 10.13801/j.cnki.fhclxb.20180930.001
Abstract:
To improve the dispersibility of nano SiO2 particles in silicon rubber (SR) and the interfacial bonding performance of the two phases, the surface modification agent consisting of hydroxyl silicone oil (HSO) and 3-(trimethoxysilyl)propylmethacrylate (KH570) for nano SiO2was designed. And the modified nano SiO2/SR composites were prepared. The morphology structure of nano SiO2 and the dispersibility of nano SiO2in the ethanol were investigated, the fracture surface morphology, mechanical properties and thermal stability of the modified nano SiO2/SR composites were also analyzed. The results show that KH570 is successfully grafted to the surface of nano SiO2 and formes chemical bonds with the SR matrix. When the nano SiO2 is treated by the hybrid surface modification agent (HSO cooperated with KH570), the dispersibility of SiO2 in SR matrix, and the interface bonding performances between SiO2 and SR are improved obviously, the mechanical properties and thermal stability of the SiO2/SR composites are also enhanced significantly. When SiO2:HSO:KH570 mass ratio is 2.0:0.2:0.6, the initial temperature of thermal decomposition of the modified nano SiO2/SR composite increases to 230℃. When SiO2:HSO:KH570 mass ratio is 2.0:0.2:0.45, the tensile strength and elongation at break of the modified nano SiO2/SR composite increase twice, respectively.
To improve the dispersibility of nano SiO2 particles in silicon rubber (SR) and the interfacial bonding performance of the two phases, the surface modification agent consisting of hydroxyl silicone oil (HSO) and 3-(trimethoxysilyl)propylmethacrylate (KH570) for nano SiO2was designed. And the modified nano SiO2/SR composites were prepared. The morphology structure of nano SiO2 and the dispersibility of nano SiO2in the ethanol were investigated, the fracture surface morphology, mechanical properties and thermal stability of the modified nano SiO2/SR composites were also analyzed. The results show that KH570 is successfully grafted to the surface of nano SiO2 and formes chemical bonds with the SR matrix. When the nano SiO2 is treated by the hybrid surface modification agent (HSO cooperated with KH570), the dispersibility of SiO2 in SR matrix, and the interface bonding performances between SiO2 and SR are improved obviously, the mechanical properties and thermal stability of the SiO2/SR composites are also enhanced significantly. When SiO2:HSO:KH570 mass ratio is 2.0:0.2:0.6, the initial temperature of thermal decomposition of the modified nano SiO2/SR composite increases to 230℃. When SiO2:HSO:KH570 mass ratio is 2.0:0.2:0.45, the tensile strength and elongation at break of the modified nano SiO2/SR composite increase twice, respectively.
2019, 36(7): 1708-1715.
doi: 10.13801/j.cnki.fhclxb.20181025.002
Abstract:
High-porosity and uniform-thickness composite separator was prepared by high-pressure electrospinning using polyethylene-vinyl alcohol sulfonate (EVOH-SO3Li) and poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) as raw materials. The performance of the EVOH-SO3Li/PVDF-HFP separator was characterized by FTIR, SEM, universal tensile tester, TGA, BMP3 electrochemical workstation and battery testing system. The test results show that the EVOH-SO3Li/PVDF-HFP separator forms a dense three-dimensional network structure with uniform fiber thickness and uniform pore size. The porosity and liquid absorption rate of EVOH-SO3Li/PVDF-HFP separator are 85% and 437%, respectively. Compared with pure EVOH-SO3Li separator, the maximum tensile strength of EVOH-SO3Li/PVDF-HFP composite separator is increased from 2.17 MPa to 8.33 MPa. The initial thermal decomposition temperature also raises to 310℃. The excellent performance of electrochemical and battery is exhibited. The electrochemical stability window is increased from 5.6 V to 5.8 V, the interfacial impedance is reduced from 425.51 Ω to 115.24 Ω, and the ionic conductivity is increased from 1.592×10-3 S/cm to 3.102×10-3 S/cm. Lithium-ion batteries assembled with EVOH-SO3Li/PVDF-HFP separators have a capacity retention rate of 96.65% after 100 cycles at 0.5 C discharge current.
High-porosity and uniform-thickness composite separator was prepared by high-pressure electrospinning using polyethylene-vinyl alcohol sulfonate (EVOH-SO3Li) and poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) as raw materials. The performance of the EVOH-SO3Li/PVDF-HFP separator was characterized by FTIR, SEM, universal tensile tester, TGA, BMP3 electrochemical workstation and battery testing system. The test results show that the EVOH-SO3Li/PVDF-HFP separator forms a dense three-dimensional network structure with uniform fiber thickness and uniform pore size. The porosity and liquid absorption rate of EVOH-SO3Li/PVDF-HFP separator are 85% and 437%, respectively. Compared with pure EVOH-SO3Li separator, the maximum tensile strength of EVOH-SO3Li/PVDF-HFP composite separator is increased from 2.17 MPa to 8.33 MPa. The initial thermal decomposition temperature also raises to 310℃. The excellent performance of electrochemical and battery is exhibited. The electrochemical stability window is increased from 5.6 V to 5.8 V, the interfacial impedance is reduced from 425.51 Ω to 115.24 Ω, and the ionic conductivity is increased from 1.592×10-3 S/cm to 3.102×10-3 S/cm. Lithium-ion batteries assembled with EVOH-SO3Li/PVDF-HFP separators have a capacity retention rate of 96.65% after 100 cycles at 0.5 C discharge current.
2019, 36(7): 1716-1727.
doi: 10.13801/j.cnki.fhclxb.20181017.002
Abstract:
Visible light responsive MoS2/Sb2S3 composite photocatalyst was successfully designed and constructed by a simple one-step hydrothermal process. XRD, SEM, UV-vis diffuse reflectance spectroscopy (UV-Vis DRS) and XPS were used to characterize its photocatalytic activity. The degradation experiment was conducted with rhodamine B (RhB) as the target pollutant. Compared with the pure Sb2S3 and MoS2, the MoS2/Sb2S3 composite photocatalyst exhibits highly enhanced efficiency in the degradation of RhB, showing excellent adsorption performance and photocatalytic performance. Compared with TiO2, Bi2S3, C3N4 and Sb2S3, MoS2/Sb2S3 composite photocatalyst is possessed as more excellent photocatalyst under the same experimental conditions. In addition, the photocatalytic degradation mechanism was carried on the exploration. This research expounds the mechanism of photocatalytic reaction, and provides a application for the photocatalyst preparation methods of degradation high concentration organic wastewater, which has certain application value.
Visible light responsive MoS2/Sb2S3 composite photocatalyst was successfully designed and constructed by a simple one-step hydrothermal process. XRD, SEM, UV-vis diffuse reflectance spectroscopy (UV-Vis DRS) and XPS were used to characterize its photocatalytic activity. The degradation experiment was conducted with rhodamine B (RhB) as the target pollutant. Compared with the pure Sb2S3 and MoS2, the MoS2/Sb2S3 composite photocatalyst exhibits highly enhanced efficiency in the degradation of RhB, showing excellent adsorption performance and photocatalytic performance. Compared with TiO2, Bi2S3, C3N4 and Sb2S3, MoS2/Sb2S3 composite photocatalyst is possessed as more excellent photocatalyst under the same experimental conditions. In addition, the photocatalytic degradation mechanism was carried on the exploration. This research expounds the mechanism of photocatalytic reaction, and provides a application for the photocatalyst preparation methods of degradation high concentration organic wastewater, which has certain application value.
2019, 36(7): 1728-1736.
doi: 10.13801/j.cnki.fhclxb.20190109.002
Abstract:
Superhydrophobic and superoleophilic graphene (GE)/formaldehyde-melamine-sodium (FMS) bisulfite copolymer sponge was synthesized by a two-step method, first polymerize GE on the sponge substrate, followed by surface modification with polymethylphenyl silicone to take advantage of its adhesion force in an effort to enhance the hydrophobicity of the FMS sponge absorbent. The modified GE/FMS sponge was characterized by FTIR, SEM, TGA and water contact angle measurement. The results show that the fabricated GE/FMS copolymer sponge is successfully embellished with GE, with a water contact angle of 158.9° after functionalization. The modified GE/FMS sponge exhibits excellent oil-water and organic solvent-water separation with stable superhydrophobic properties maintained after 20 times of absorption-desorption engine oil. The sponge sorbent displays a high sorption capacity with chloroform and engine oil for the modified GE/FMS sponge amounted to about 125 times and 90 times its own weight respectively. The GE/FMS sponge can also separate oil or organic solvent from water efficiently from simulated separation process. The GE/FMS sponge sorbent shows a recovery rate of greater than 87% for the absorption of oils and organic solvents tested. Further, the separation of oil or organic solvent was simulated, overall the newly developed GE/FMS sponge shows much better performance in terms of sorption capacity, recovery rate and reusability, which makes the GE/FMS sponge a promising sorbent for potential applications in the separation and recovery of spilled oils from water.
Superhydrophobic and superoleophilic graphene (GE)/formaldehyde-melamine-sodium (FMS) bisulfite copolymer sponge was synthesized by a two-step method, first polymerize GE on the sponge substrate, followed by surface modification with polymethylphenyl silicone to take advantage of its adhesion force in an effort to enhance the hydrophobicity of the FMS sponge absorbent. The modified GE/FMS sponge was characterized by FTIR, SEM, TGA and water contact angle measurement. The results show that the fabricated GE/FMS copolymer sponge is successfully embellished with GE, with a water contact angle of 158.9° after functionalization. The modified GE/FMS sponge exhibits excellent oil-water and organic solvent-water separation with stable superhydrophobic properties maintained after 20 times of absorption-desorption engine oil. The sponge sorbent displays a high sorption capacity with chloroform and engine oil for the modified GE/FMS sponge amounted to about 125 times and 90 times its own weight respectively. The GE/FMS sponge can also separate oil or organic solvent from water efficiently from simulated separation process. The GE/FMS sponge sorbent shows a recovery rate of greater than 87% for the absorption of oils and organic solvents tested. Further, the separation of oil or organic solvent was simulated, overall the newly developed GE/FMS sponge shows much better performance in terms of sorption capacity, recovery rate and reusability, which makes the GE/FMS sponge a promising sorbent for potential applications in the separation and recovery of spilled oils from water.
2019, 36(7): 1737-1745.
doi: 10.13801/j.cnki.fhclxb.20181009.002
Abstract:
In order to overcome the disadvantage of low activity of the ZnO nanocrystals under visible light irradiation, the six square wurtzite spong-like ZnO nanocrystals were prepared by liquid phase co-precipitation thermal decomposition method with zinc nitrate hexahydrate, hexamethylene tetramine and oxalic acid dihydrate as the raw materials. The as-prepared spong-like ZnO were composited with Ag2O nanocrystals under alkaline condition. The obtained Ag2O/ZnO composite photocatalysts were characterized by XRD, FTIR, UV-Vis diffuse reflection spectroscopy (UV-Vis DRS), FESEM, TEM and BET analysis. The dark adsorption and photocatalytic acivity of the Ag2O/ZnO composite photocatalysts with different mole ratios were investigated with formaldehyde (HCHO) as a degradation model using visible light source. The results indicate that with the increase of Ag2O, the dark adsorption of HCHO increases first and then decreases with the maximum removal of 43.34% in which the mole ratio of Ag2O to ZnO is 1:5. On the other hand, the best degradation effect is achieved when the mole ratio of Ag2O to ZnO is 1:10, and the photodegradation of HCHO also increases first and then decreases under visible light with 78% photodegradation of HCHO and 85% of HCHO total removal after 90 min of visible light irradiation.
In order to overcome the disadvantage of low activity of the ZnO nanocrystals under visible light irradiation, the six square wurtzite spong-like ZnO nanocrystals were prepared by liquid phase co-precipitation thermal decomposition method with zinc nitrate hexahydrate, hexamethylene tetramine and oxalic acid dihydrate as the raw materials. The as-prepared spong-like ZnO were composited with Ag2O nanocrystals under alkaline condition. The obtained Ag2O/ZnO composite photocatalysts were characterized by XRD, FTIR, UV-Vis diffuse reflection spectroscopy (UV-Vis DRS), FESEM, TEM and BET analysis. The dark adsorption and photocatalytic acivity of the Ag2O/ZnO composite photocatalysts with different mole ratios were investigated with formaldehyde (HCHO) as a degradation model using visible light source. The results indicate that with the increase of Ag2O, the dark adsorption of HCHO increases first and then decreases with the maximum removal of 43.34% in which the mole ratio of Ag2O to ZnO is 1:5. On the other hand, the best degradation effect is achieved when the mole ratio of Ag2O to ZnO is 1:10, and the photodegradation of HCHO also increases first and then decreases under visible light with 78% photodegradation of HCHO and 85% of HCHO total removal after 90 min of visible light irradiation.
2019, 36(7): 1746-1752.
doi: 10.13801/j.cnki.fhclxb.20181113.001
Abstract:
The rice husk biochar/acetate starch-urea (RHBC/AS-UR) composite films were prepared by casting method with different AS:UR:RHBC mass ratios of 8:1:1, 8:2:1, 8:4:1, respectively. The micromorphology and structure properties of the RHBC/AS-UR composite films were investigated by SEM, FTIR, XRD and TGA. The RHBC/AS-UR composite-coated UR fertilizers were prepared in a spouted fluidized bed coating equipment and its release characteristics were tested. The results show that the rice husk biochar can be uniformly dispersed in the RHBC/AS-UR composite film and has good bonding with AS-UR in a "solid bridge" structure. In the mean time, the thermal stability of RHBC/AS-UR composite films is enhanced by adding RHBC. The adding of UR can improve the ductility of RHBC/AS-UR composite film. When the mass fraction of UR is 18.2wt%, the best mechanical properties of the RHBC/AS-18.2wt%UR composite film can be reached and the elongation at break increases by 500%. Compared to the pure UR granule without and with RHBC/AS-UR coating, the UR coated with different mass ratios of RHBC/AS-UR composite films can effectively reduce the release rate of UR-N. The total release rate of RHBC/AS-18.2wt%UR coated UR is the lowest (only 81%), which exhibits better slow-release property.
The rice husk biochar/acetate starch-urea (RHBC/AS-UR) composite films were prepared by casting method with different AS:UR:RHBC mass ratios of 8:1:1, 8:2:1, 8:4:1, respectively. The micromorphology and structure properties of the RHBC/AS-UR composite films were investigated by SEM, FTIR, XRD and TGA. The RHBC/AS-UR composite-coated UR fertilizers were prepared in a spouted fluidized bed coating equipment and its release characteristics were tested. The results show that the rice husk biochar can be uniformly dispersed in the RHBC/AS-UR composite film and has good bonding with AS-UR in a "solid bridge" structure. In the mean time, the thermal stability of RHBC/AS-UR composite films is enhanced by adding RHBC. The adding of UR can improve the ductility of RHBC/AS-UR composite film. When the mass fraction of UR is 18.2wt%, the best mechanical properties of the RHBC/AS-18.2wt%UR composite film can be reached and the elongation at break increases by 500%. Compared to the pure UR granule without and with RHBC/AS-UR coating, the UR coated with different mass ratios of RHBC/AS-UR composite films can effectively reduce the release rate of UR-N. The total release rate of RHBC/AS-18.2wt%UR coated UR is the lowest (only 81%), which exhibits better slow-release property.
2019, 36(7): 1753-1760.
doi: 10.13801/j.cnki.fhclxb.20180927.001
Abstract:
The nano-SnO2-Fe2O3 composites were prepared by hydrothermal synthesis method and were used as the active material for lithium-ion batteries. The multi-walled carbon nanotubes (MWCNTs) conductive paper was used as the collector instead of traditional copper foil. The lithium-ion batteries were assembled with SnO2-Fe2O3/MWCNTs conductive paper as anode and metal lithium foil as the counter electrodes. The structure and physical properties of electrodes were characterized by XRD and SEM. The results show that SnO2-Fe2O3 is uniformly intercalated in the bores of the 3D conductive network constructed by MWCNTs. The results of electrochemical tests show that SnO2-Fe2O3/MWCNTs conductive paper electrodes can improve the cycle and rate performance of lithium-ion batteries significantly. The specific capacity of SnO2-Fe2O3/MWCNTs conductive paper electrode can reach 1088 mAh/g at the current density of 100 mA/g after 30 cycles. The specific capacity of SnO2-Fe2O3/MWCNTs conductive paper can maintain at 898 mAh/g with 200 mA/g current density after cycling 200 cycles. The specific capacity of SnO2-Fe2O3/MWCNTs conductive paper decreases with the increase of the current density, but the coulombic efficiency still remain above 96%. While the current increases to 1 600 mA/g, the capacity of SnO2-Fe2O3/MWCNTs conductive paper still maintain at 547 mAh/g. The specific capacity of SnO2-Fe2O3/MWCNTs conductive paper can recover to 1 000 mAh/g while the current reduces to 100 mA/g, and SnO2-Fe2O3/MWCNTs conductive paper exhibit excellent rate performance.
The nano-SnO2-Fe2O3 composites were prepared by hydrothermal synthesis method and were used as the active material for lithium-ion batteries. The multi-walled carbon nanotubes (MWCNTs) conductive paper was used as the collector instead of traditional copper foil. The lithium-ion batteries were assembled with SnO2-Fe2O3/MWCNTs conductive paper as anode and metal lithium foil as the counter electrodes. The structure and physical properties of electrodes were characterized by XRD and SEM. The results show that SnO2-Fe2O3 is uniformly intercalated in the bores of the 3D conductive network constructed by MWCNTs. The results of electrochemical tests show that SnO2-Fe2O3/MWCNTs conductive paper electrodes can improve the cycle and rate performance of lithium-ion batteries significantly. The specific capacity of SnO2-Fe2O3/MWCNTs conductive paper electrode can reach 1088 mAh/g at the current density of 100 mA/g after 30 cycles. The specific capacity of SnO2-Fe2O3/MWCNTs conductive paper can maintain at 898 mAh/g with 200 mA/g current density after cycling 200 cycles. The specific capacity of SnO2-Fe2O3/MWCNTs conductive paper decreases with the increase of the current density, but the coulombic efficiency still remain above 96%. While the current increases to 1 600 mA/g, the capacity of SnO2-Fe2O3/MWCNTs conductive paper still maintain at 547 mAh/g. The specific capacity of SnO2-Fe2O3/MWCNTs conductive paper can recover to 1 000 mAh/g while the current reduces to 100 mA/g, and SnO2-Fe2O3/MWCNTs conductive paper exhibit excellent rate performance.
2019, 36(7): 1761-1768.
doi: 10.13801/j.cnki.fhclxb.20180930.002
Abstract:
The ion-responsive poly(1-vinyl-3-ethylimidazolium tetrafluoroborate) (PVEIm+BF4-)@CaO microcapsule was synthesized by phase separation. By the ion-exchange of BF4- on the poly(ionic liquids) (PILs) with Cl- in water, the hydrophobic crosslinked PILs shell can be converted to hydrophilic and formed hydrophilic channels in water. The CaO in microcapsules can be released to water through the channels and transferred to Ca(OH)2. The addition of PVEIm+BF4-@CaO microcapsule to NaCl solution can reduce the Cl- concentration from 8.3 mmolL-1 to 5.8 mmolL-1 and increase the pH from 7.00 to 11.83 simultaneously. The release rate of CaO shows a direct relationship with ionic liquids (ILs) content and the mass ratio of styrene(St):divinylbenzene(DVB). The increase of Cl- concentration can result in the increase of CaO release rate. The CaO can be completely released to NaCl solution from PVEIm+BF4-@CaO microcapsules consisted with different mass ratios of monomers or triggered by various concentrations of Cl-. The maximum Ca2+ concentrations in the solution are similar, which is about 3.4 mmolL-1. SO42- can also trigger the release of microcapsule. The results show that the PVEIm+BF4-@CaO microcapsules are sensitive to Cl- and SO42-. The concentration ratio of Cl-/OH- decreases significantly after the PVEIm+BF4-@CaO microcapsules adding, which is beneficial to improve the corrosion resistance of steel bars to Cl-.
The ion-responsive poly(1-vinyl-3-ethylimidazolium tetrafluoroborate) (PVEIm+BF4-)@CaO microcapsule was synthesized by phase separation. By the ion-exchange of BF4- on the poly(ionic liquids) (PILs) with Cl- in water, the hydrophobic crosslinked PILs shell can be converted to hydrophilic and formed hydrophilic channels in water. The CaO in microcapsules can be released to water through the channels and transferred to Ca(OH)2. The addition of PVEIm+BF4-@CaO microcapsule to NaCl solution can reduce the Cl- concentration from 8.3 mmolL-1 to 5.8 mmolL-1 and increase the pH from 7.00 to 11.83 simultaneously. The release rate of CaO shows a direct relationship with ionic liquids (ILs) content and the mass ratio of styrene(St):divinylbenzene(DVB). The increase of Cl- concentration can result in the increase of CaO release rate. The CaO can be completely released to NaCl solution from PVEIm+BF4-@CaO microcapsules consisted with different mass ratios of monomers or triggered by various concentrations of Cl-. The maximum Ca2+ concentrations in the solution are similar, which is about 3.4 mmolL-1. SO42- can also trigger the release of microcapsule. The results show that the PVEIm+BF4-@CaO microcapsules are sensitive to Cl- and SO42-. The concentration ratio of Cl-/OH- decreases significantly after the PVEIm+BF4-@CaO microcapsules adding, which is beneficial to improve the corrosion resistance of steel bars to Cl-.
2019, 36(7): 1769-1775.
doi: 10.13801/j.cnki.fhclxb.20181023.002
Abstract:
In order to develop an effective adsorbent for Cd ions removal, activated carbon (AC) was prepared with rice husk and modified with pentaethylenehexamine (PEHA). The batch adsorption were studied for AC and AC-PEHA to determine the effect of contact time, initial Cd ions concentration and solution pH on the Cd ions ions uptake. The effect of HCl concentration on desorption efficiency for Cd ions was discussed as well. SEM, FTIR and BET surface area analysis were used to characterize the structure, morphology and properties of AC and AC-PEHA. The results show that the adsorption equilibrium are achieved for both AC and AC-PEHA at react time 60 min, and adsorption kinetics are well described by the pseudo-second-order model. Comparing with AC, The adsorption capacities of AC-PEHA for Cd ions increase from 26.15 mgg-1 to 53.58 mgg-1 at initial Cd ions concentration of 10-350 mgL-1 and pH of 5.0. The adsorption of Cd ions on AC-PEHA is more favourable under alkaline condition (pH=6-8). The maximum Cd ions desorption of 83.8% for AC-PEHA occurs with 30 gL-1 HCl. Although the total pore volume and average pore width of AC decrease by 21.6% and 7.4% respectively after PEHA modification, the modification add more primary amine groups to AC pores, and it significantly enhances the Cd ions adsorption capacity of AC.
In order to develop an effective adsorbent for Cd ions removal, activated carbon (AC) was prepared with rice husk and modified with pentaethylenehexamine (PEHA). The batch adsorption were studied for AC and AC-PEHA to determine the effect of contact time, initial Cd ions concentration and solution pH on the Cd ions ions uptake. The effect of HCl concentration on desorption efficiency for Cd ions was discussed as well. SEM, FTIR and BET surface area analysis were used to characterize the structure, morphology and properties of AC and AC-PEHA. The results show that the adsorption equilibrium are achieved for both AC and AC-PEHA at react time 60 min, and adsorption kinetics are well described by the pseudo-second-order model. Comparing with AC, The adsorption capacities of AC-PEHA for Cd ions increase from 26.15 mgg-1 to 53.58 mgg-1 at initial Cd ions concentration of 10-350 mgL-1 and pH of 5.0. The adsorption of Cd ions on AC-PEHA is more favourable under alkaline condition (pH=6-8). The maximum Cd ions desorption of 83.8% for AC-PEHA occurs with 30 gL-1 HCl. Although the total pore volume and average pore width of AC decrease by 21.6% and 7.4% respectively after PEHA modification, the modification add more primary amine groups to AC pores, and it significantly enhances the Cd ions adsorption capacity of AC.
2019, 36(7): 1776-1786.
doi: 10.13801/j.cnki.fhclxb.20181025.001
Abstract:
The graphene oxide (GO) was preparaed by natural flake graphite, then it was reduced to graphene(RGO) by Zn. ZnO is attached to the surface of RGO. The structure, morphology, degree of oxidation, electromagnetic loss properties, Debye relaxation and microwave absorbing properties of ZnO/RGO composite were investigated by XRD, Raman, SEM, TEM, FTIR and vector network analyzer (VNA). The results show that when the reduction temperature is 50℃, the structure of RGO is more complete after reduction and the layer spacing is 0.89 nm, the permittivity and permeability of ZnO/RGO composite are higher. At 17.15 GHz, the reflectivity of ZnO/RGO composite is -41.2 dB, the bandwidth of the reflection loss of ZnO/RGO composite below -10 dB is 3.67 GHz.
The graphene oxide (GO) was preparaed by natural flake graphite, then it was reduced to graphene(RGO) by Zn. ZnO is attached to the surface of RGO. The structure, morphology, degree of oxidation, electromagnetic loss properties, Debye relaxation and microwave absorbing properties of ZnO/RGO composite were investigated by XRD, Raman, SEM, TEM, FTIR and vector network analyzer (VNA). The results show that when the reduction temperature is 50℃, the structure of RGO is more complete after reduction and the layer spacing is 0.89 nm, the permittivity and permeability of ZnO/RGO composite are higher. At 17.15 GHz, the reflectivity of ZnO/RGO composite is -41.2 dB, the bandwidth of the reflection loss of ZnO/RGO composite below -10 dB is 3.67 GHz.
