Enhanced Thermal, Optical and Mechanical Performance of Copolyimide Composite Film Filled with TSP-POSS

A substrate is one critical factor for the wide application of flexible displays and electronic packaging materials in the future. Polyimides with high optical transparency, good thermal stability, dielectric properties, and nice mechanical properties are significant in substrates. A simple and feasible method to modify transparent polyimide films is to blend them with inorganic fillers. In this work, we successfully modified the transparent films by using phenyltriethoxysilane to synthesize trisilanol phenyl polyhedral silsesquioxane and adding it to the films. The introduction of trisilanol phenyl polyhedral silsesquioxane into the copolymer films resulted in the increase of high-temperature dimensional stability, optical performance, and mechanical properties of the films. The sample containing 5% of trisilanol phenyl polyhedral silsesquioxane exhibited a glass transition temperature of 322°C, coefficient of thermal expansion of 41.4 ppm/K, and tensile strength of 127 MPa, and the transmittance at 450 nm has reached 83.5%.