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

摘要

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℃/mjn. 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℃ and 340-400℃. 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℃ and 340-400℃, 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.