A simple strategy to prepare functional PI microspheres by constructing coating on PAA microspheres followed thermal imidization reaction

Abstract

With the development of downstream applications, functionalized polyimide (PI) composites have gradually become a research hotspot. The traditional approaches to prepare functional PI are complex and time-consuming, which are not suitable for large-scale production. In this paper, a three-step strategy for PI microspheres functionalization through PAA microsphere preparation, functional material cladding and thermal imidization is proposed. First, polyamide acid (PAA)-the precursor of polyimide, was prepared in the form of microspheres with a mean particle size of about 2 μm by water vapor induced phase separation (WVIPS) method. Subsequently, the functional fillers like TiO2 and graphene oxide have been successfully coated on the surface of PAA microspheres by hydrogen bonding and electrostatic adsorption force, respectively. It is worthy to note that the coated microspheres exhibiting well stability after the thermal imidization process. This work provided a facile and efficient strategy for the fabrication of functionalized PI composites.