Effect of mold temperature and additive migration on scratch behavior of TPOs at elevated temperatures

Abstract Scratch performance of thermoplastic olefins (TPOs) has been considered one of the required properties for automotive applications. The scratch resistance of TPOs can be enhanced by utilization of commonly used slip additives such as erucamide. When TPOs are injection molded, the mold temperature impacts the migration of the slip additive toward the surface and the surface crystallinity of the TPOs, which has been shown to influence scratch resistance. In order to evaluate the effect of the mold temperature and erucamide migration on scratch behavior at elevated temperatures, this research has adopted the ASTM D7027/ISO 19252 linearly increasing normal load scratch test methodology to investigate the scratch behavior of the model TPOs at 25 °C, 50 °C, and 75 °C. This study provides a comprehensive understanding on the effects of mold temperature, slip additive, elevated testing temperature, and thermal aging on scratch behavior of TPOs.