Tailoring of 4-vinylpyridine-based resins for hydrolytic degradation and solubilisation

Gel-type and macroporous 4-vinylpyridine-derived polymer resins have been prepared by suspension polymerisation employing ethylene glycol diacrylate, ethylene glycol dimethacrylate or divinylbenzene as the crosslinker. Each resin has also been converted into its pyridinium ion form via methylation using methyl iodide, in effect producing the corresponding anion exchange resins. The hydrolytic stability under both acidic and alkaline conditions of both the neutral and the cationic forms of all the resins has been assessed. Crosslinks derived from the diacrylate monomer are the most hydrolytically labile whereas the dimethacrylate derived crosslinks cleave only under basic conditions and when the resin is in its quaternised form. Remarkably a gel-type resin lightly crosslinked using divinylbenzene also degrades under similar conditions, and since the crosslink itself is likely to be stable it seems that mainchain scission is involved in this instance. (C) 1999 Elsevier Science Ltd. All rights reserved.