The colored poly(m-phenylene isophthalamide)(PMIA)spinning solution was prepared by wet spinning and the die-swell of the colored PMIA spinning solution was done when it was extruded from a die in this experiment.The ...The colored poly(m-phenylene isophthalamide)(PMIA)spinning solution was prepared by wet spinning and the die-swell of the colored PMIA spinning solution was done when it was extruded from a die in this experiment.The properties and structures of colored PMIA fibers were characterized by scanning electron microscopy(SEM).The colored PMIA spinning dopes were first commixed in a pressurizer and then spun into a coagulation bath.The effect of die swell on the colored PMIA solution was resulted from the viscoelastic properties of the colored PMIA solution in the spinning process.The results showed that the die-swell ratio of the colored PMIA solution increased linearly with increasing the pressure and die length/diameter ratio(L/D).At the same pressure and L/D,the die-swell ratio decreased with the increase of filter layers and temperature.Also,optimized spinning parameters of the dopedyed PMIA fiber were obtained.展开更多
In order to solve the problem of oily wastewater,the poly(m-phenyleneisophthalamide)(PMIA)braided tube reinforced(PBR)poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether)(PFA)hollow fiber membrane with thermal and...In order to solve the problem of oily wastewater,the poly(m-phenyleneisophthalamide)(PMIA)braided tube reinforced(PBR)poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether)(PFA)hollow fiber membrane with thermal and solvent resistant property was prepared via no-solvent green method.The membrane surface and pore structure was optimized by changing the sintering temperature and graphene(GE)content.The morphologies showed that the spherical surface with good lipophilicity was formed,and the excellent mechanical strength with a favorable interface bonding state could be obtained due to the PFA melts permeating into the supporting layer.The doping of GE produced synergistic effects with the sintering temperature owing to its good thermal conductivity and pore formation.The PBR-PFA/GE hollow fiber membrane exhibited good hydrophobicity and lipophilicity with more than 97%separation efficiency for different oil products at-0.02 MPa.With the addition of GE,the average pore size first increases and then decreases,and the porosity gradually decreases.In addition,the hollow fiber membrane showed high separation ability to the water-in-oil emulsion,and maintained a stable flux recovery rate after recycling,making it possible to apply in the field of oily wastewater treatment.展开更多
A series of flexible poly(m-phenylene isophthalamide)(PMIA)-based composites with different sizes and mass fractions of hexagonal boron nitride(hBN)were successfully manufactured for the first time via the casting tec...A series of flexible poly(m-phenylene isophthalamide)(PMIA)-based composites with different sizes and mass fractions of hexagonal boron nitride(hBN)were successfully manufactured for the first time via the casting technique.The effects of modified hBN particles on microstructure,mechanical properties,dielectric properties and thermal conductivities of fabricated composites were investigated.The results indicate that modified hBN particles manifest good compatibility with the PMIA matrix.The Young's modulus and Theat-resistance index of PMIA-based composites are increased with increasing the mass fraction of hBN particles.Due to additional thermal conductive paths and networks formed by nano-sized hBN particles,the K-m/n-hBN-30 composite displays the thermal conductivity of 0.94 W·m^-1·K^-1 higher than that of the K-m-hBN-30 composite(0.86 W·m^-1·K^-1),and more than 4 times higher than that of neat PMIA.Moreover,the obtained PMIA-based composites also show low dielectric constant and ideal dielectric loss.Owing to the excellent comprehensive performance,hBN/PMIA composites present potential applications in the broad field of electronic materials.展开更多
Poly(m-phthaloyl-m-phenylenediamine)(PMIA)is promising as the separator in lithium-ion batteries(LIBs)for its excellent thermostability,insulation and self-extinguishing properties.However,its low mechanical strength ...Poly(m-phthaloyl-m-phenylenediamine)(PMIA)is promising as the separator in lithium-ion batteries(LIBs)for its excellent thermostability,insulation and self-extinguishing properties.However,its low mechanical strength and poor electrolyte affinity limit its application in LIBs.In this work,a new PMIA@polyacrylonitrile-polyvinylidene fluoride hexafluoropropylene-titanium dioxide(PMIA@PAN/PVDFHFP/TiO_(2))composite fibrous separator with a coaxial core-shell structure was developed by combining coaxial electrospinning,hot pressing,and heat treatment techniques.This separator not only inherits the exceptional thermostability of PMIA,showing no evident thermal shrinkage at 220 ℃,but also reveals improved mechanical strength(29.7 MPa)due to the formation of firm connections between fibers with the melted PVDF-HFP.Meanwhile,the massive polar groups in PVDF-HFP play a vital role in improving the electrolyte affinity,which renders the separator a high ionic conductivity of 1.36×10^(-3)s/cm.Therefore,the LIBs with PMIA@PAN/PVDF-HFP/TiO_(2)separators exhibited excellent cycling and rate performance at 25℃,and a high capacity retention rate(76.2%)at 80℃for 200 cycles at 1 C.Besides,the lithium metal symmetric battery assembled by the separator showed a small overpotential,indicating that the separator had a role in inhibiting lithium dendrites.In short,the PMIA@PAN/PVDF-HFP/TiO_(2) separator possesses a wide application prospect in the domain of LIBs.展开更多
文摘The colored poly(m-phenylene isophthalamide)(PMIA)spinning solution was prepared by wet spinning and the die-swell of the colored PMIA spinning solution was done when it was extruded from a die in this experiment.The properties and structures of colored PMIA fibers were characterized by scanning electron microscopy(SEM).The colored PMIA spinning dopes were first commixed in a pressurizer and then spun into a coagulation bath.The effect of die swell on the colored PMIA solution was resulted from the viscoelastic properties of the colored PMIA solution in the spinning process.The results showed that the die-swell ratio of the colored PMIA solution increased linearly with increasing the pressure and die length/diameter ratio(L/D).At the same pressure and L/D,the die-swell ratio decreased with the increase of filter layers and temperature.Also,optimized spinning parameters of the dopedyed PMIA fiber were obtained.
基金funding provided by the National Natural Science Foundation of China(52103035,52173038).
文摘In order to solve the problem of oily wastewater,the poly(m-phenyleneisophthalamide)(PMIA)braided tube reinforced(PBR)poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether)(PFA)hollow fiber membrane with thermal and solvent resistant property was prepared via no-solvent green method.The membrane surface and pore structure was optimized by changing the sintering temperature and graphene(GE)content.The morphologies showed that the spherical surface with good lipophilicity was formed,and the excellent mechanical strength with a favorable interface bonding state could be obtained due to the PFA melts permeating into the supporting layer.The doping of GE produced synergistic effects with the sintering temperature owing to its good thermal conductivity and pore formation.The PBR-PFA/GE hollow fiber membrane exhibited good hydrophobicity and lipophilicity with more than 97%separation efficiency for different oil products at-0.02 MPa.With the addition of GE,the average pore size first increases and then decreases,and the porosity gradually decreases.In addition,the hollow fiber membrane showed high separation ability to the water-in-oil emulsion,and maintained a stable flux recovery rate after recycling,making it possible to apply in the field of oily wastewater treatment.
基金the Natural Science Foundation of Shanghai(Grant No.17ZR1401100)the National Natural Science Foundation of China(Grant No.51473031).
文摘A series of flexible poly(m-phenylene isophthalamide)(PMIA)-based composites with different sizes and mass fractions of hexagonal boron nitride(hBN)were successfully manufactured for the first time via the casting technique.The effects of modified hBN particles on microstructure,mechanical properties,dielectric properties and thermal conductivities of fabricated composites were investigated.The results indicate that modified hBN particles manifest good compatibility with the PMIA matrix.The Young's modulus and Theat-resistance index of PMIA-based composites are increased with increasing the mass fraction of hBN particles.Due to additional thermal conductive paths and networks formed by nano-sized hBN particles,the K-m/n-hBN-30 composite displays the thermal conductivity of 0.94 W·m^-1·K^-1 higher than that of the K-m-hBN-30 composite(0.86 W·m^-1·K^-1),and more than 4 times higher than that of neat PMIA.Moreover,the obtained PMIA-based composites also show low dielectric constant and ideal dielectric loss.Owing to the excellent comprehensive performance,hBN/PMIA composites present potential applications in the broad field of electronic materials.
基金supported by the Natural Science Foundation of Sichuan Province(Nos.2023YFG0096,2022NSFSC2008 and 2023NSFSC0442).
文摘Poly(m-phthaloyl-m-phenylenediamine)(PMIA)is promising as the separator in lithium-ion batteries(LIBs)for its excellent thermostability,insulation and self-extinguishing properties.However,its low mechanical strength and poor electrolyte affinity limit its application in LIBs.In this work,a new PMIA@polyacrylonitrile-polyvinylidene fluoride hexafluoropropylene-titanium dioxide(PMIA@PAN/PVDFHFP/TiO_(2))composite fibrous separator with a coaxial core-shell structure was developed by combining coaxial electrospinning,hot pressing,and heat treatment techniques.This separator not only inherits the exceptional thermostability of PMIA,showing no evident thermal shrinkage at 220 ℃,but also reveals improved mechanical strength(29.7 MPa)due to the formation of firm connections between fibers with the melted PVDF-HFP.Meanwhile,the massive polar groups in PVDF-HFP play a vital role in improving the electrolyte affinity,which renders the separator a high ionic conductivity of 1.36×10^(-3)s/cm.Therefore,the LIBs with PMIA@PAN/PVDF-HFP/TiO_(2)separators exhibited excellent cycling and rate performance at 25℃,and a high capacity retention rate(76.2%)at 80℃for 200 cycles at 1 C.Besides,the lithium metal symmetric battery assembled by the separator showed a small overpotential,indicating that the separator had a role in inhibiting lithium dendrites.In short,the PMIA@PAN/PVDF-HFP/TiO_(2) separator possesses a wide application prospect in the domain of LIBs.
