Polyimide nanocomposite coating materials with special functions

摘要

Sol-gel-based imide nanocomposite coating systems have been synthesized using 3,3'4,4'-benzophenonetetracarboxylic dianhydiide (BTDA) and y-aminopiopylttimethoxysilane (APTS) as precursors. This basic system, where the imide group starts to form at 140°C, was used as a basis for adding the third function of SiC>2 nanoparticles for hardness, SiO2/graphite for wear resistance, graphite/PTFE for lubrication, or fluorosilanes for low surface free energy. The results show that these combinations lead to a coefficient of friction u. as low as 0,11, a wear coefficient of k = 5x10"6 mm3/Nm and surface free energy of 18 mJ/m2, Practical tests in an automotive clutch showed a superior behaviour compared to conventional coating systems.