Thermal degradation kinetics and thermodynamics of maleimide-sytrene based alternating copolymer: A comparative investigation of monomer and polymer structures

Abstract

Thermal degradation of N-(4-(3-Thienyl methylene)-oxycarbonylphenyl) maleimide monomer, MT and its copolymer with styrene, P(MT-alt-St) were investigated comparatively using TG and DTA methods. Degradation of monomer takes place in three stages which correspond to removal of thiophene, aliphatic groups and the rest of structural decomposition respectively. Degradation of the copolymer occurs in two stages. Thiophene and aliphatic groups decompose simultaneously at the first degradation stage. The main polymeric chain remains intact. The second stage is related to the rest of structural decomposition. Activation energy values of these reactions were calculated by using Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods. In order to determine the effective reaction model and calculate thermodynamic parameters, these methods were combined with modeling equations. It was found that the first degradation stages of monomer and copolymer show good harmony with diffusion model (D1), whereas nucleation and growth model (A2) is effective for the second decomposition stage of the monomer.