Polyimide‐epoxy alloys prepared via micro‐modification: Water sorption and diffusion

Abstract

AbstractA novel polyimide‐epoxy or PI‐EP alloys are prepared by the modification of polyamic acid in the concentration range of 1.54×10−6 to 1.54×10−2 mol/L. The methanol sorption for these alloys at 24 hrs and at equilibrium conditions are determined and the residual solvent in fully cyclized polyimides were calculated. The presence of the residual solvent is visualized in fully imidized polymer and a structure containing partly imidized amic acid moiety is proposed and their concentration (in percentage) is calculated. The water sorption for these alloys at 24 hrs and at equilibrium conditions and the values of the water diffusion coefficient are determined from absorption isotherms. The PI‐EP alloys have shown comparatively lower water sorption and higher diffusion coefficient than the unmodified polyimide. The mechanistic aspects of water sorption and diffusion are discussed.