Preparation of a Ductile Biopolyimide Film by Copolymerization

We developed ductile biopolyimide (BPI) films derived from a renewable aromatic diamine, 4,4'-diaminotruxillic acid, with a mixture of two different dianhydrides. The BPI copolymers show high thermal resistance with T-10 values of over 406 degrees C and T-g values of over 208 degrees C, improved tensile strength and elongation at break, and a Young's modulus maintained at around 4 GPa. In addition, the copolymers showed an adhesion strength to the carbon plate of 0.22-4.47 MPa, which: is similar to that of cyanoacrylate superglue. In summary, we develop tough films composed of the copolymers derived from benzophenonetetracarboxylic dianhydride and oxydiphthalic dianhydride., The film shows a strain energy as high as that of a commercial Kapton film. We confirm the ductility of the film by microscopy and tensile testing after it was completely folded.