Epoxy laminated composites reinforced with polyethyleneimine functionalized carbon fiber fabric: Mechanical and thermal properties

Epoxy (EP) laminated composites reinforced with polyethyleneimine (PEI) functionalized carbon fiber fabric (CFF), which were prepared by pre-depositing polydopamine on the surface of pristine CFF and then further grafting with PEI, were fabricated and their mechanical and thermal properties were investigated in detail. The flexural strength and flexural modulus of PEI-functionalized CFF/EP composites were 32% and 31% greater than that of as-received CFF/EP composites. The interlaminar shear strength and thermal expansion coefficient of PEI-functionalized CFF/EP composites were 55 ± 2 MPa and 48.9 ppm/°C, improved by 34% and 16.8% compared with the as-received CFF/EP composites. Microstructure and thermal analyses revealed that the PEI-functionalization of CFF enhanced interfacial adhesion due to the increase of interfacial crosslinking density, which causes by the curing reaction between EP and PEI. The PEI-functionalized CFF/EP composites achieve a combination of excellent in-plane and out-of-plane properties, thereby holding enormous potential in many application fields.