Cross-linking of polystyrene by Friedel-Crafts chemistry

The alkylation of polystyrene with a difunctional alkylating agent, either 1,4-benzenedimethanol or 2,2'-biphenyldimethanol, proceeds in the presence of a zeolite catalyst to give a significant amount of dress-linked, and thermally stable, polymer. Various zeolites are used as catalysts; there is apparently some relationship between the type of zeolite and its catalytic activity. Tile extent of cross-linking depends upon-temperature. With some zeolites there is no reaction below 300 degrees C while others will permit reaction below 300 degrees C.