Ferroelectric polymer poly(vinylidene fluoride)(PVDF)shows excellent electro-activity and is promising for flexible electronic devices.However,the processing of PVDF into the favourable ferroelectric structure(β-phas...Ferroelectric polymer poly(vinylidene fluoride)(PVDF)shows excellent electro-activity and is promising for flexible electronic devices.However,the processing of PVDF into the favourable ferroelectric structure(β-phase)presents difficulties,while its copolymer with trifluoroethylene(PVDF-TrFE)can directly crystallize into β-phase,but shows limited thermal stability and high-cost processing.As a result,an easily implementable method,pressing-and-folding(P&F),was used to produce highly compatible blended films of PVDF and PVDF-TrFE without using any hazardous solvent or complex polymer processing equipment.Hot-pressed PVDF(molecular weight:530 kg/mol)and PVDF-TrFE(molar ratio:51/49)films were firstly stacked before undergoing P&F treatment.Compared to extrusion-blended films before and after P&F,the P&F stacked films showed isotropic crystalline structure of b-phase,as confirmed using X-ray diffraction and infrared spectroscopy.The ferroelectric remnant polarization of the P&F stacked films is 0.068 C/m^(2),surpassing pure PVDF-TrFE(0.062 C/m^(2))and the simulated value of remnant polarization of pure PVDF(~0.065 C/m^(2)).The above findings promise to provide inspirations for new processing strategy on PVDF-based functional polymers.展开更多
An novel compounding process using nano-CaCO_(3) aqueous suspension for preparing polymer/nano-CaCO_(3) composites with nanoparticles dispersed at the nanoscale is reported.The process is called the mild mixing method...An novel compounding process using nano-CaCO_(3) aqueous suspension for preparing polymer/nano-CaCO_(3) composites with nanoparticles dispersed at the nanoscale is reported.The process is called the mild mixing method.In this method,the pre-dispersed nano-particle suspensions are blended with melting polymers in a weak shearing field using an extruder,followed by removing the water from the vent.The four typical poly-meric nanocomposites were prepared by mild mixing method.The dispersion of nano-CaCO_(3) in the matrix of the polymer at the nanoscale was confirmed by scanning electron microscopy(SEM).The molecular weights of polycarbonate(PC)and its nanocomposite showed that the degradation had not occurred during the mild mixing processing.The mechanical properties of the composite with 1.5 wt-% nano-CaCO_(3) improve slightly.It proved that this approach is suitable for the preparation of nano-composites based on both polar and non-polar polymers.展开更多
基金This work is sponsored by National Natural Science Foundation of China(52103024)Fundamental Research Funds for the Central Universities(2232021D-01)+2 种基金Shanghai Pujiang Program(20PJ1400600)the fellowship of the China Postdoctoral Science Foundation(2021M690646)Engineering and Physical Sciences Research Council(EPSRC)(EP/L017695/1).
文摘Ferroelectric polymer poly(vinylidene fluoride)(PVDF)shows excellent electro-activity and is promising for flexible electronic devices.However,the processing of PVDF into the favourable ferroelectric structure(β-phase)presents difficulties,while its copolymer with trifluoroethylene(PVDF-TrFE)can directly crystallize into β-phase,but shows limited thermal stability and high-cost processing.As a result,an easily implementable method,pressing-and-folding(P&F),was used to produce highly compatible blended films of PVDF and PVDF-TrFE without using any hazardous solvent or complex polymer processing equipment.Hot-pressed PVDF(molecular weight:530 kg/mol)and PVDF-TrFE(molar ratio:51/49)films were firstly stacked before undergoing P&F treatment.Compared to extrusion-blended films before and after P&F,the P&F stacked films showed isotropic crystalline structure of b-phase,as confirmed using X-ray diffraction and infrared spectroscopy.The ferroelectric remnant polarization of the P&F stacked films is 0.068 C/m^(2),surpassing pure PVDF-TrFE(0.062 C/m^(2))and the simulated value of remnant polarization of pure PVDF(~0.065 C/m^(2)).The above findings promise to provide inspirations for new processing strategy on PVDF-based functional polymers.
基金The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China(Grant No.10590351)Sichuan University Youth Science Foundation(Grant No.06007).
文摘An novel compounding process using nano-CaCO_(3) aqueous suspension for preparing polymer/nano-CaCO_(3) composites with nanoparticles dispersed at the nanoscale is reported.The process is called the mild mixing method.In this method,the pre-dispersed nano-particle suspensions are blended with melting polymers in a weak shearing field using an extruder,followed by removing the water from the vent.The four typical poly-meric nanocomposites were prepared by mild mixing method.The dispersion of nano-CaCO_(3) in the matrix of the polymer at the nanoscale was confirmed by scanning electron microscopy(SEM).The molecular weights of polycarbonate(PC)and its nanocomposite showed that the degradation had not occurred during the mild mixing processing.The mechanical properties of the composite with 1.5 wt-% nano-CaCO_(3) improve slightly.It proved that this approach is suitable for the preparation of nano-composites based on both polar and non-polar polymers.
