Non-isothermal kinetic analysis of UHMWPE sheet

Abstract Thermal decomposition behavior of ultra high molecular weight polyethylene (UHMWPE) is studied through thermogravimetric analysis technique. Thermograms are recorded at four different heating rates (2.5, 5, 10, 15 and 20 ℃/min) in nitrogen environment. These thermograms revealed that the thermal decomposition of UHMWPE occurred in three different stages. Among these stages, second stage of decomposition is highly complex. Therefore, deconvoluted into two peaks by using bi-Gaussian asymmetric function. Kinetic triplets related to these peaks are determined by adopting two iso-conversional kinetic models (Starink (SR) and Friedman (FR)). The reaction mechanism is also identified by using integral master plot method. Finally, thermodynamic parameters viz. change in entropy (∆S), change in enthalpy (∆H) and change in Gibbs free energy (∆G) are estimated at considered heating rates.