In situ polymerization of modified graphene/polyimide composite with improved mechanical and thermal properties

The graphene oxide was modified by coupling agent (KH-550). The polyimide/graphene treated by KH-550 (PI/KG) composite were prepared by in situ polymerization from 4,4'-diaminodiphenyl ether (ODA), 2,2-bis(4-(3,4-dicarboxyphenoxy)phenyl)propane dianhydride (BPADA), and modified graphene. The structure and morphology of the composite membranes were analyzed by Fourier transform infrared spectroscopy (FT-IR) and X ray diffraction. Compared to pure PI system, the tensile strength and elongation at break of PI/KG-4 composite, increasing by 26.4 and 24.1 %, was 134 MPa and 9.8 %, respectively. The 5 % mass loss temperature of polyimide system was about 486.1 degrees C, and the PI/KG-6 composite was 493.8 degrees C. PI/KG composites have a better thermal stability and a higher thermal conductivity compared to PI system with the increasing of KG content.