SIDE-CHAIN FUNCTIONALIZATION OF POLYSTYRENE WITH MALEIC-ANHYDRIDE IN THE PRESENCE OF LEWIS-ACIDS

Polystyrenes with different molecular weights were chemically modified with maleic anhydride by use of certain cationic catalysts of Lewis a cid type (BF3 . OEt(2), AlCl3, TiCl4, ZnCl2, FeCl3, and SnCl4) in chlo roform. The effects of molecular weight of polystyrene, as well as typ e of Lewis acid used, on properties and structure of products were inv estigated. The interrelation between the molecular weight of polystyre ne and content of carboxyl groups in the products was made. A direct r elationship between the activity of catalyst used and the number of ca rboxyl groups was found. For characterization of side-chain functional ized polystyrene, fractional precipitation was applied which yielded c arboxyl groups in all fractions. The carboxyl group concentrations wer e found to be the highest in the case of BF3 . OEt(2). Modified polyst yrene samples containing - CO - CH = CH - COOH fragments in side chain s are easily crosslinked at 140-150 degrees C and by UV irradiation as proved by IR, DTA, and TGA analyses. Functionalized polymers obtained are characterized by their high thermostability, adhesion, and photos ensitivity. (C) 1996 John Wiley & Sons, Inc.