Synthesis and evaluation of photolytically and thermally crosslinkable polyimide copolymers with diacetylene functionality

The polyimide block copolymers with diacetylene functionality were prepared in a two‐step process: (1) oligomeric imide formation terminated with 1‐amino‐3‐ethynylbenzene, and (2) oxidative coupling of the acetylene‐terminated polyimides with p‐ and/or m‐diethynylbenzene or bispropargyl ether of Bisphenol A to form block copolymers, or oxidative coupling within themselves in the presence of a copper (I) catalyst. The resulting copolymers were crosslinked with UV irradiation or thermal treatment. The thermal crosslinking process and the thermal stability of the crosslinked materials were studied by differential scanning calorimetry (DSC) and isothermal gravimetric analysis (IGA), respectively.