| Expandable polystyrene (EPS) is the preferred raw material for making polystyrene foam patterns that finds use in various applications, including as a construction material for buildings, spacecraft insulation, and as pattern mold in metal casting processes. Thus, information regarding the physicochemical behavior of EPS could be used for material and process development. In this study, the decomposition kinetics and gas diffusion characteristics of EPS foams have been investigated.;The goal of the kinetic study was to understand the effects of heating rate and gaseous environment on the decomposition behavior of EPS. Laboratory-scale kinetic experiments (both low and high heating rates) were carefully designed to collect pyrolysis data that were later used to estimate values for kinetic parameters, including activation energy and pre-exponential constant. A thorough review of literature on the available kinetic models have been presented and discussed. During the course of this study, a simple, yet effective, fast pyrolysis technique has been demonstrated for studying decomposition kinetics of various materials, including polymers and bio-mass.;Diffusion studies focused towards understanding the gas diffusion behavior through expanded polymeric foams from a multiscale perspective. An experimental technique was developed to collect gas transmission data for both monolithic polymer films and expanded foams. An existing coarse multiscale model available in the literature was further developed to account for the diffusion anomalies due to certain morphological features of the foam. The experimental data was utilized to validate the multiscale behavior and estimate the fractional contribution of the individual diffusion mechanisms. Results highlight the significance of the multiscale model in exploring and understanding the microstructure of the foam. |
