Structure and properties of polyimide fiber prepared from polyamic acid solution with high solid content and low viscosity

The polyamic acid (PAA) solutions with high solid content and low viscosity derived from 3,3',4,4'-biphe-nyldianhydride (BPDA)/p-phenylene diamine (PDA) were synthesized via heat treatment and partial chemical imidization, and the structure and properties of the corresponding polyimide (PI) fibers were studied. The results show that both heat treatment and partial chemical imidization can destroy the gel network structure without affecting the molecular weight of PAA, and restore the fluidity of PAA gel with high solid content. The PI fibers prepared from the PAA solution with high solid content and low viscosity have better mechanical properties, which is attributed to the high solid content reduces the internal structural defects of the nascent PAA fibers caused by dual-diffusion effect in the coagulation bath stage.

Automated summary

In this study, polyamic acid solutions with high solid content and low viscosity were synthesized through heat treatment and partial chemical imidization. The structure and properties of the corresponding polyimide fibers were investigated. The results showed that high solid content polyamic acid solutions can result in polyimide fibers with improved mechanical properties.