STUDY OF THERMAL DECOMPOSITION OF THE COPOLYMER BASED ON POLYETHYLENE GLYCOL FUMARATE WITH METHACRYLIC ACID

Abstract

Thermal performance of copolymer based on polyethylene glycol fumarate and methacrylic acid in a dynamic mode, in an inert nitrogen environment are considered in the present work. Kinetic evaluation of thermal decomposition process was conducted using three different data processing methods (Friedman, Ozawa-Flynn-Wall, Kissinger-Akahira-Sunose). Utilizing a mixed-method approach kinetic triplets Eа, A, g(a) were received. The received kinetic parameters were used to calculate the thermodynamic characteristics of Gibbs energy (∆G), enthalpy (∆H) and entropy of activation (∆S). Copolymer thermal gravimetric analysis (TGA) and differential thermogravimetric analysis (DTA) curves were studied under nitrogen environment using a heating rate of 2,5, 5, 10 or 20°C/min. The method of Invariant Kinetic Parameters was used to identify the reaction model and pre-exponential factor. The main phase of copolymer decomposition was set, which occurred within a narrow temperature interval and is evidenced by the spike on the differential curve. Values for 13 reaction models were received. Utilised methods resulted in a proper energy activation alignment within 223-229 kJ mol-1. Design and experimental data provided close values. TGA and DTA curve analysis has shown a sufficient thermal stability of these copolymers under the nitrogen environment.