Evaluation of expanded perlite behavior in PS/Perlite composites

Abstract In this study, composites based on PS/Perlite were prepared with 10 (P10) and 20 (P20) wt% of perlite by melt mixing in a twin screw extruder. The perlite effect was assessed by the composites morphological, thermal, mechanical and rheological properties. The photographs obtained by SEM revealed that some perlite's particles broke during the processes. Thermal analysis results showed that the addition of perlite did not affect the thermal stability of the PS matrix, but reduced its glass transition temperature about 20 °C. The comparison of the tensile property values indicated that perlite increased the elastic modulus by 23% and 31% for P10 and P20 composites, respectively, but also caused premature fracture of the materials. The rheology of PS/Perlite composites was evaluated at dynamic mode. The results revealed that the mineral filler addition to the PS matrix decreased the system's viscosity, highlighting its lubricant effect, which may be an interesting behavior for production of thermoformed packings with insulation ability, when compared to the neat PS.