Preparation, curing properties, and phase morphology of epoxy-novolac resin/multiepoxy-terminated low-molecular-weight poly(phenylene oxide) blend

The multiepoxy-terminated low-molecular-weight poly (phenylene oxide) (PPOE) was synthesized by modifying the terminal hydroxyl group of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) with epoxy-novolac resin (EPN). The curing kinetics, phase morphology, and thermal stability of the cured EPN/PPOE blends were investigated and compared to the unmodified EPN/PPO and EPN/EPPO (epichlorohydrin-modified PPO) blends. As revealed by the Fourier transform infrared and differential scanning calorimetry analyses, PPOE took part in the curing reaction and formed a crosslinked structure with EPN. The curing rate of EPN/PPOE blends first increased and then decreased with the increase of PPOE fraction. PPOE had both catalytic and steric hindrance effects on the curing reaction. EPN/PPOE blends showed faster curing rate and higher degree of curing than the corresponding EPN/PPO and EPN/EPPO blends. The reactive blending improved the dispersion of PPOE in EPN matrix and the thermal stability of the blend. POLYM. ENG. SCI., 54:2595–2604, 2014. © 2013 Society of Plastics Engineers