Effects of rubber particle size and type on scratch performance were investigated using two types of styrenic copolymers: acrylonitrile styrene acrylate (ASA) and acrylonitrile butadiene styrene (ABS). ASAs with rubber particle sizes of 100 nm and 1 mu m, respectively, and ABS with rubber particle size of 100 nm were examined. Linearly increasing normal load scratch tests were performed according to the ASTM D7027/ISO 19252 standard. A noticeable drop in scratch resistance is found in ASA with 100 nm rubber particles when compared to ASA containing 1 mu m rubber particles. ABS is observed to exhibit a higher scratch resistance when compared to ASA with comparable rubber particle size. Detailed deformation and damage mechanisms have been investigated to explain the observed differences in scratch performance of the model systems. Implication of the present findings for design of scratch resistant polymers is discussed. (C) 2015 Elsevier Ltd. All rights reserved.