Cross-linking of polystyrene by Friedel-Crafts chemistry to improve thermal stability

Copolymers which contain either alcohol or chloride functionalized polystyr ene units have been prepared and they participate in Friedel-Crafts chemist ry to give cross-linked polymers by the evolution of either hydrogen chlori de or water. Proof of cross-linking comes from the identification of the ev olved gas, the insolubility of the product. and the thermal resistance of t he newly formed polymer. The onset temperature for the degradation is raise d by about 100 degrees C relative to that of polystyrene and the fraction w hich is not volatile at 800 degrees C ranges from 10% for the alcohol copol ymers to 20% for the chloride copolymers. (C) 1999 Elsevier Science Ltd. Al l rights reserved.