Hydroxy-containing low molecular weight poly（2,6-dimethyl-1,4-phenylene oxide）（r PPO） and self-promoted hydroxycontaining phthalonitrile（HPPH） were prepared by redistribution reaction and the simple nucleophilic displacement of a nitro-substituent from 4-nitrophthalonitrile in a dipolar aprotic solvent respectively. The hydroxy-containing phthalonitriles modified by r PPO were prepared by mechanical blending without compatibilizer, followed by heating. The curing behavior was studied using dynamic rheological analysis, and the results showed that the r PPO-modified phthalonitrile exhibited a large processing window（over-67 °C） and complex viscosity（0.18-0.8 Pa·s） at moderate temperatures. After curing at 300 °C, the resulting polymers showed good thermal stability and high modulus as observed by thermogravimetric analysis（TGA） and dynamic mechanical analysis（DMA）. The dielectric properties and the morphology of r PPO-modified phthalonitrile networks were studied by dielectric analysis and field-emission scanning electron microscopy（SEM）.
Jing-Zhi MaKang ChengJiang-Bo LvChang ChenJiang-Huai HuKe ZengGang Yang
A series of polymer blends were prepared from 1,3-bis（3,4-dicyanophenoxy）benzene（3 BOCN） and epoxy resin with methyl tetrahydrophthalic anhydride as curing agent. The curing behavior and curing kinetics of the blends were studied by differential scanning calorimetry. The apparent activation energy of the blends with various contents of 3 BOCN was higher than that of the blends without 3 BOCN. A model experiment suggested that there is no obvious reaction between phthalonitrile and epoxy. The thermal and mechanical properties of the polymer blends were evaluated. The polymer blends exhibit high storage modulus and char yield compared with the neat epoxy. The polymer blends show ductile fracture morphology by scanning electron microscopy（SEM） images.
