Low-Dielectric Constant and Low-Temperature Curable Polyimide/POSS Nanocomposites

With the rapid development of ultra large scale integrated circuits, low stress, low thermal expansion, low dielectric constant, and low temperature curable (<250 degrees C) polyimides (PIs) with excellent mechanical, thermal properties are required. Unfortunately, high curing temperatures above 300 degrees C and limited dielectric property still remain to be solved. Herein, a new type of aminopropyl isobutyl polysilsesquioxane (POSS) with single vertex activity is introduced by in situ polymerization resulting in the PI-POSS nanocomposites which exhibit a low dielectric constant (kappa <= 2.6). Furthermore, low-temperature curing at 200 degrees C (99.4% imidization) under the catalysis of quinoline is also achieved. The as-prepared PI-POSS nanocomposites also show excellent mechanical properties of which the tensile strength can reach up to 148 MPa and the elongation at break achieves 98%. Moreover, the temperature of weight loss 5% is as high as 550 degrees C and the glass transition temperature can also reach 349 degrees C. The as-prepared PI-POSS nanocomposites prove excellent electrical performance and mechanical properties, showing a huge market prospect of 5G chip packaging and millimeter wave antenna in the future.