Phthalide Cardo Chain Extended Siloxane Core Skeletal Modified Polyimide/Multi-Walled Carbon Nanotube Nanocomposites

A new type of siloxane core modified phthalide cardo chain based polyimide (PI) was successfully prepared from siloxane core dianhydride and ether linked phenolphthalein diamine moiety. This PI was further modified with different weight percentages of multi-walled carbon nanotubes (MWCNTs) to obtain MWCNT reinforced PI nanocomposites. The enhancement in the glass transition temperature and improved thermal stability could be afforded by the restrained motion of polymeric chain, caused from nanoreinforcement effect of MWCNTs. The successive increment in the concentration of MWCNTs resulted in augmented dielectric constant because of interfacial polarization of MWCNTs. This PI shows better solubility and low water uptake percentage of 0.42–0.58%. The morphological studies ascertain the molecular level dispersion of MWCNT throughout the PI matrix.