Glass transition temperatures of epoxy modified with pendent nano-organic rigid-rod compounds

Abstract

Pendent nanoscale organic rigid-rod compounds are molecular fiber-like materials that can be used to reinforce the polymer matrix. In this study, 4,4'-diphenylmethane diisocyanate (MDI) was used to covalently connect a number of organic rigid-rod compounds [4'-hydroxyphenyl-4-hydroxy-benzoate (HPHB), phenyl 4-hydroxybenzoate (HPB), 4,4'-isopropylidenediphenol (BSPA), and 2-naphthol (NPT)] to the secondary hydroxyl groups of the epoxy resin. These reactions were monitored using Fourier transform infrared (FTIR) spectroscopy; the products were characterized using nuclear magnetic resonance (NMR) spectroscopy. The glass transition temperatures of the organic rigid-rod compounds modified epoxy resins were investigated through differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Thermogravimetric analysis (TGA) was used to detect the values of Td and the thermal stabilities of the polymers.