Reclaimed tire rubber and polyolefin blends

Abstract

The effect of blend ratio, compatibilization and dynamic curing system using sulphur, peroxide and mixed system on impact, tensile strength and swelling ratio of RTR/polyolefin blends were investigated. Increasing the RTR loading lead to the increase of impact strength to a maximum at the loading of 50 pbw for the blends with all polyethylenes and 60 pbw for the one with polypropylene. At higher loading, the impact strength of each blend was dropped. This was probably attributed to the large amount of carbon black that was already present in RTR that was critical point for the improvement. The highest impact strength and tensile strength of RTR/HDPE blends was obtained by sulphur vulcanization, by sulphur-peroxide mixed system for RTR/LDPE or LLDPE blends, and by peroxide for RTR/PP blends. Crosslink density determined by solvent swelling ratio, agreed well with the mechanical test results. These suggested that there was high degree of the filler-matrix interaction. The phase structure and miscibility of the two components in the blend at various compositions were assessed by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Rheological behavior was also studied to understand the effect of shear rate on the flow behavior and elasticity of the materials.