Some observations on the copolymerization of styrene with furfuryl methacrylate

The tendency for crosslinking to occur either during free radical polymerization in solution or to develop subsequently in air after precipitation of linear polymer has been observed for both polymerization of furfuryl methacrylate (FM) and copolymerization of FM with styrene (ST). Reactivity ratios rFM=0.33±0.08 and rST=0.44±0.02 have been determined. Thermo-oxidative stability is lowered by incorporation of FM moieties into poly-ST. Glass transition temperatures (Tg) of copolymers accord with the Fox equation and extrapolation affords a value of 64°C for the Tg of linear poly-FM. After admixture of solutions of poly(FM-co-ST) and bismaleimide (BM) at ambient temperature crosslinked gel is produced slowly by intermolecular Diels–Alder reaction between diene units (FM) and the dienophile (BM). The retro Diels–Alder reaction occurs rapidly on heating, regenerating linear copolymer and BM. The crosslinked gels exhibit considerable swelling in chloroform and toluene.