Thermal Analysis Kinetics of the Chemical Crosslinking Reaction of the Styrene-Based Block Copolymer SEEPS

Abstract

The chemical crosslinking reaction of styrene-[ethylene-(ethylene-propylene)]-styrene block copolymer (SEEPS) using the crosslinker benzoyl peroxide was analyzed by non-isothermal differential scanning calorimetry (DSC). Based on the DSC curves at different heating rates, the thermal kinetics of the SEEPS crosslinking reaction was analyzed with the Friedman and Ozawa-Flynn-Wall model-free methods. After applying the model-fit method to the system, precise kinetic equations and parameters were determined. The kinetics model indicates there are three steps in the crosslinking reaction. This optimized model can be used to predict the relationship between the conversion and the reaction time at different temperatures. The model illustrates that SEEPS with various crosslinking degrees can be obtained by controlling the reaction temperature and time. Evaluation of the thermal analysis kinetics was an effective way to select suitable processing conditions to control the crosslinking reaction in SEEPS. Keywords: SEEPS, Chemical crosslinking, Differential scanning calorimetry, Thermal analysis kinetics, Chemical Crosslinking Reaction, Styrene-Based Block Copolymer SEEPS, crosslinker benzoyl peroxide, non-isothermal differential scanning calorimetry (DSC), Ozawa-Flynn-Wall model-free, model-fit method, multi-purpose thermoplastic elastomer, ultraviolet light, ambient conditions, thermal analysis kinetics (TAK), Multiple non-linear regression, activation energy, isoconversional method, Friedman Method, Ozawa-Flynn-Wall Method, DSC curves