Thermosetting Polyimide Stretch Film

Compared to " Kapton" film of" Du Pont", our native polyimide(PI) film can not afford advanced usage. In order to improve the properties , especially the mechanical property of PI film, we, according to some studies, creat a new processing method , cast-stretching method.We get the idea from the fact: in order to get PI, we must first synthesize polyamide acid(PAA), then second cure PAA in the high temperature. PAA is still of line molecule, and can be resolved in polar solvents. So we can stretch PAA casted-film, and finally cure it. After stretching, macromolecule of PAA film can arrange down the drawing way. This compact structure will lead to high mechanics of PI film.This paper discusses the cast-stretching technics from five parts: synthesization of PAA, casting of PAA film, stretching (monoaxially and biaxially) of PAA film and solidification of PAA. We study and confirm the influential factors in these five parts. Mainly we make sure the proper qualification of stretching film, the influence of drawing on the properties of PI film, and then through Small Angle Laser Scattering(SALS) and DSC, we analyse the influence of stretching on the microcosmic structure of PI.This paper indicates that cast-stretching method can effectively enhance the performance of PI film, satisfying the high need today.