A detailed study of thermal degradation of poly(2-hydroxyethyl methacrylate)

The thermal degradation behaviour of poly-2-hydroxyethyl methachrylate and of its deuterium derivative have been studied using thermogravimetry under nitrogen atmosphere, with programmed heating at 10°C/min. At first, the partially degraded polymer has been examined by IR. The cold ring fraction (CRF) was trapped at two ranges from ambient temperature to 340°C and 340–400°C. These CRFs were characterized by IR, 1H, 13C NMR, and GC–MS. When the polymer decomposes thermally at two temperature ranges which are from ambient temperature to 340°C and 340–400°C, at both CRFs, the major product is monomer due to depolymerisation reaction. The side products arising from ester decomposition are a six-membered glutaric anhydride type of ring, an oxolane type of ring, 2-isopropenyl ethyl methacrylate, methacrylic acid and CO 2. A mechanism which accounts for all these products has been formulated. The activation energy for the thermal degradation of poly(HEMA) is predicted as 129.8 kJ/mol