Influence of different ratios of a-ODPA/a-BPDA on the properties of phenylethynyl terminated polyimide

A series of phenylethynyl-terminated imide oligomers based on 3,4'-oxydianiline (3,4'-ODA), with different content of 2,3,3',4'-oxydiphthalic dianhydride (a-ODPA) and 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA), have been prepared by chemical imidization process. The effects of different dianhydrides ratios on curing behavior, solubility, melt viscosity of oligomers, glass transition temperature (T-g), coefficient of thermal expansion (CTE), thermal stability, mechanical performance of films, and adhesive properties were evaluated systematically. The prepared oligomers with more content of a-ODPA exhibited sufficient solubility in some solvents, lower melt viscosity and better adhesion. The cured resins with more content of a-BPDA exhibited lower CTE value, higher T-g and thermal stability in N-2 and air atmosphere. The T-g value of the cured a-BPDA/3,4'-ODA/PEPA system (Oligo-5) was 338 degrees C by tan delta. Meanwhile, the obtained polyimide films based on a-ODPA/a-BPDA monomers possessed high tensile strength (> 98.0 MPa) and strain (> 10.3%). These detailed results may provide some help to choice suitable matrix resin for structural adhesive and high-performance resin-based composite materials.