Non-isothermal decomposition kinetics of in-chain functionalized poly(MMA-co-ethylene)

Abstract

Efficient incorporation of polar monomers in polyolefin can lead to many desirable properties in the parent chain. Herein, we report the synthesis of ethylene and methyl methacrylate (MMA)-based copolymers by transition metal-catalysed reverse atom transfer radical polymerization technique with controlled ethylene feed pressure. Successful copolymerization was confirmed by 1H nuclear magnetic resonance analysis. With increasing polymerization time, resultant copolymers exhibit bimodal molecular weight distributions with controlled high molecular weight component and less-controlled low molecular weight component as confirmed by size-exclusion chromatography analysis. Morphological and crystal structures of the copolymer were established using scanning electron microscope and X-ray diffraction analysis, respectively. Thermogravimetric analysis of the copolymer under non-isothermal condition shows a two-step decomposition process with the major decomposition in the range of 320–450 °C. Based on approaches of Friedman and Flynn–Wall–Ozawa, model-free multivariate nonlinear regression analyses were performed to find out the formal mechanisms, kinetic model and its corresponding kinetic triplets. The results revealed the nth-order (Fn) mechanism responsible for the decomposition of the copolymer. The estimated kinetic parameters for the decomposition of poly(MMA-co-ethylene) copolymer were Ea= 227.80 kJ mol−1 and A = 6.76 × 1015 s−1.