PMMA stability under hydrothermal conditions

Abstract

PMMA is a synthetic polymer of methyl methacrylate. PMMA is used widely in many applications and the interest in their physicochemical properties is growing. In this work, a hydrothermal study was carried out to evaluate the PMMA stability under hydrothermal conditions (up to 200°C), pH (2−10) and reaction time (up to 360 min). The water-PMMA system is affected by different mechanisms when dosed with bases or acids suggesting predominantly an interaction of ester groups with the medium. The results prove that the polymer is highly stable at the tested conditions. It is observed that water molecules are encapsulated in the polymer due to the softening and hardening during the process. This phenomenon was seen in the thermogravimetric analysis. The glass transition temperature of PMMA was slightly reduced after the treatment. This suggests that the hydrothermal process promotes the degradation of the shortest polymeric chains.