Study On The Preparation And Performance Of Polyacrylonitrile-based Composite Piezoelectric Materials

Piezoelectric polymer has the advantages of softness,light weight and can be processed into any shape.The preparation process is simple,which solves the problems of brittle and difficult polarization of piezoelectric ceramics.The traditional piezoelectric polymer is polyvinylidene fluoride?PVDF?,which has poor high-temperature piezoelectric stability and low melting point,so it is difficult to meet the application in some specific high-temperature fields.In solid state,PAN has two kinds of molecular conformations,namely,3¹ helix conformation and plane sawtooth conformation.Plane sawtooth conformation corresponds to the piezoelectric properties of PAN.In the high temperature environment,the molecular conformation of PAN tends to shift to the 3¹helix conformation,which will reduce its piezoelectric performance.In view of the above problems,in this paper,PAN-based composite piezoelectric materials were prepared by electrospinning.The research contents are as follows:Firstly,PAN/inorganic salt composite fiber membrane was prepared,and the effects of the amount of inorganic salt and spinning speed on the piezoelectric properties of PAN/inorganic salt composite fiber membrane were studied.Through FTIR,XRD,mechanical properties,piezoelectric properties and their stability tests,the conclusion is as follows:when the doping inorganic salt is Al Cl₃,Na NO₃,Fe Cl₃·6H₂O,the doping amount is 0.9%,0.9%,12%,respectively,and the spinning speed is 1000 mm/s,1000mm/s,1100 mm/s,the piezoelectric properties are the best.After high temperature relaxation heat treatment,the piezoelectric properties of the composite fiber membrane doped with inorganic salts are higher than that of the pure PAN fiber membrane.Secondly,PAN/PVDF composite fiber membrane was prepared,and the effect of the ratio of PVDF on the piezoelectric properties of composite fiber membrane was studied.When the ratio of PAN to PVDF is 70:30,the piezoelectricity of the composite fiber membrane is the best.Through DSC,mechanical properties,FTIR and XRD test,it is confirmed that there is an interaction between PAN and PVDF,which is conducive to improve the piezoelectric properties and piezoelectric stability of the composite fiber membrane.Finally,PAN and GO composite fiber membrane was prepared.Through FTIR,XRD,DSC,mechanical properties and piezoelectric properties test,the conclusion is as follows:when the amount of GO doping is 0.75%,the piezoelectricity of the fiber membrane is the best.The interaction force between PAN and GO is conducive to improve the piezoelectric properties and piezoelectric stability of the fiber membrane.In this paper,PAN,inorganic salt,polymer and nanoparticles were successfully compounded to prepare composite piezoelectric materials.Their piezoelectric properties and piezoelectric stability were improved.This composite piezoelectric material will have important significance and application value in the field of high temperature.