Effects of molecular weight and thermal history on scratch behavior of polypropylene thin sheets

The effects of molecular weight (Mw) and thermal history on the scratch behavior of polypropylene (PP) thin sheets and a commercial thermoplastic olefin (TPO) have been investigated. Scratch parameters like the critical load for onset of scratch visibility and scratch coefficient of friction (SCOF) were utilized in this evaluation. The results suggest that scratch performance is improved when the Mw and surface crystallinity of PP are high. Correlation between scratch resistance and surface crystallinity of PP is established and discussed. Approaches for the preparation of scratch-resistant TPOs are also addressed.