Preparation of imide-siloxane/silica nanocomposite membrane

Abstract

In this work, supported polyimide-siloxane hybrid membranes containing different percentages of silica were successfully prepared from pyromellitic dianhydride (PMDA), aminopropyltrimethoxysilane (APrTMOS) and tetramethoxysilane (TMOS) by polycondensation, imidisation and sol-gel reaction. Membranes were coated on supports by spin coating method and the film thickness was 1-3μm. The molecular structure and thermal performance of these membranes were characterized by using Fourier transform-infrared spectrometry (FT-IR) and thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) was used to study the quality of coatings. The results indicated the presence of imide and Si-O-Si bonds in the sample. Weight loss of the hybrid polyimide membrane was reduced 29% compared to the pure polyimide. No defects or cracks were observed on the substrate/coating interface.