COPOLYMERS OF 2-VINYL-4,4-DIMETHYLAZLACTONE WITH STYRENE AND ETHYL ALPHA-HYDROXYMETHYLACRYLATE

The monomer reactivity ratios for copolymerization of 2-vinyl-4,4-dimethylazlactone (VA) and ethyl alpha-hydroxymethylacrylate (EHMA) were 0.20-0.24 and 0.53-0.74, respectively, which show that EHMA is slightly more reactive with VA than with itself and should lead to random copolymers favoring alternation. The VA-styrene (VA-St) system also has a tendency to form random copolymers but with increased tendency for alternation with both r1 and r2 between 0.18-0.22. T(g)'s of VA-EHMA and VA-St copolymers varied between 100 and 136-degrees-C, and 96 and 117-degrees-C, respectively. Thermolysis of VA-EHMA copolymers resulted in crosslinking via the ring-opening reaction of VA groups by EHMA alcohols, followed by transesterification involving EHMA units at higher temperatures leading to highly crosslinked structures. The preformed dimer of EHMA and VA was also synthesized and found to be an effective crosslinking agent in free radical vinyl polymerizations.