THERMAL-DECOMPOSITION OF CROSS-LINKED POLYMERS OF SOME DIMETHACRYLATE ESTERS

The thermal decomposition behaviour of a series of dimethacrylate monomers and their crosslinked polymers were investigated by pyrolysis-gas chromatography. The formation of the corresponding monomers and methacrylic acid was monitored to evaluate the relative importance of the two processes, depolymerization and ester group decomposition. As expected, the predominance of either of these processes depends very much upon the structure of the ester, but for most of the polymers investigated there was no clear correlation between it and the amount of monomer liberated. In the case of a sulphur-containing polymer the predominant process of pyrolysis is ester group decomposition and methacrylic acid formation due to the presence of a weak C-S bond and easily abstractable H atoms.