Spectroscopic and Thermal Investigations on Methyl Methacrylate – co – Methacrylic Acid Copolymer

Abstract

Gamma irradiation effects on methyl methacrylate (MMA) – methacrylic acid (MAA) copolymer were investigated by spectroscopic (ESR, FTIR) and thermal (DSC) methods. Electron spin resonance (ESR) spectra of the irradiated copolymer are analysed to be caused by different component spectra from the free radicals (~ CH2 – CH – CH2 ~ and – COOH or – COOCH3) as per computer simulation analysis. The ESR signals could be annealed near the transition temperature of the copolymer, and the free radicals formed irradiation might react to form stable structures at transition temperatures. Fourier transform infrared (FTIR) studies suggested that the 3380 cm-1 absorption band (due to COOH groups and or hydrogen bonding) and 1734 cm-1 absorption band (due to carbonyl groups) were mostly affected by irradiation. Differential scanning calorimeter (DSC) thermogram indicated that the copolymer is a two-phase system (PMMA and PMAA), and transition temperatures are influenced by gamma irradiation. The dosimetric application of copolymer is tested by the ESR technique, and it was found suitable for dosimetry.