Investigation of scratch behavior of PC/PBT blend

Blend of polycarbonate (PC) and polybutylene terephthalate (PBT) has wide range of applications including automotive parts where aesthetic properties are important. This study aims to study the scratch behavior of PC/PBT blends in the 0-100 wt% range of compositions. Blends were made via melt compounding technique. Scratch hardness of specimens were measured and the scratch behavior of them were evaluated via optical microscopy. These images revealed the scratch behavior transition of the blends from brittle damages for PBT to smooth and homogenous surface for PC. Pure PC and its 20% PBT blend had the best scratch resistance due to the smooth scratch behavior and plastic flow during scratch test. As the PBT content increased, the ability of the blend for plastic flow decreased and regular fractures formed in the scratch groove. It was shown that scratch mechanism directly affects scratch resistance and varies smoothly as composition of the blend changes