Development and preparation of high‐performance thermoplastic vulcanizates based on blends of natural rubber and thermoplastic polyurethanes

Abstract

AbstractNatural rubber (NR)/thermoplastic polyurethane (TPU) blends were prepared with a dynamic vulcanization technique. The main objective was to prepare high‐performance thermoplastic vulcanizates (TPVs) based on natural rubber [thermoplastic natural rubber (TPNR)] with low hardness values and improved thermal and mechanical properties. In this study, the preparation of dynamically cured NR/TPU blends was carried out systematically, and the final properties were compared to those of typical commercial TPVs. The influence of sulfur‐cured systems, accelerator types, process parameters, and rubber types were investigated. The developed NR/TPU‐based TPNRs showed better tensile strengths and thermal properties than commercial TPVs with similar hardnesses. Moreover, the epoxidized natural rubber (ENR)/TPU‐based TPNRs exhibited a low compression set. The incorporation of NR into the TPU reduced the Shore A hardness to about 60 in comparison to a value of about 85 for the neat TPU; the blends also showed improved oil resistance (oil swelling = 12%) in comparison to commercial TPVs with similar hardnesses. The experimental results indicate that high‐performance TPNRs with low hardness values could be prepared with the proper conditions developed in this study. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013