New Colorless and Transparent Poly(ether imide) Derived from a Biobased Plant Oil (Anethole): Synthesis and Properties

Starting from anethole, a biobased plant oil, a new monomer containing Wagner–Jauregg-type imide units was synthesized via cascade double Diels–Alder reaction. The reaction between the monomer and decafluorobiphenyl gave a colorless and transparent poly(ether imide) film, which exhibited a transmittance of more than 85% at 450 nm and a cutoff wavelength of less than 292 nm. Such a new polyimide also displayed high thermostability with 5% weight loss temperature (Td5) of more than 413 °C, a glass transition temperature (Tg) of higher than 364 °C, and a coefficient of thermal expansion (CTE) of lower than 30 ppm/°C. Moreover, the polymer exhibited good mechanic properties with tensile strength of 1.87 GPa and modulus of 53.3 MPa. These data indicate that the new polyimide is suitable as the plastic substrate for the application in the display industry.