Scale‐dependent tribological response and mechanical consequences of adding a SAN ‐Derived Anti‐Scratch Additive to ABS and PP

Abstract

The motorcycle sector increasingly relies on polymeric components for weight reduction, cost control and aesthetic performance,which makes surface integrity—and particularly scratch resistance—a critical design requirement. This studyevaluates the effect of a commercial SAN-basedanti-scratchmasterbatch (MB), originally designed for styrenic matrices, at10 wt% on two commonly used polymers, acrylonitrile–butadiene–styrene (ABS) and polypropylene (PP). The additive concentrationwas selected according to the manufacturer´s recommendation for industrial applications. Compression-moldedplates were characterized by DSC and FTIR to assess thermo-chemicalmodifications, while surface performance wasprobed at two length scales by nanoscratch (SPM) and pin-on-diskabrasion tests. Bulk mechanical behavior was examinedvia nanoindentation, tensile, fracture and impact testing. The additive reduced nanoscale friction and groove depth in ABSbut produced only marginal or no improvement in PP. At the macroscale, ABS+MB exhibited a lower friction coefficient yeta small increase in wear rate; PP+MB displayed increased wear and a tendency toward lower tensile properties and stiffness.These outcomes are consistent with partial plastification and improved local compatibility in ABS, versus poor interfacialadhesion and decreased crystallinity in PP. By intentionally comparing a compatible (ABS) and a noncompatible (PP) matrix,the results highlight the strong dependence of additive efficacy on matrix chemistry and morphology, rather than suggestinggeneral applicability. The findings emphasize that nanoscale improvements do not necessarily translate into better bulkwear performance and that additive formulation must be tailored to the polymer class.