Abrasive wear studies on maleic anhydride modified polypropylene and polyethylene terephthalate blends

Abstract

Polypropylene and polyethylene terephthalate (PP/PET) blends have been developed, with and without maleic anhydride (MAH), by using a melt and mixing method. Abrasive wear loss in PP/PET blends having 5, 10, 20, and 50 wt% of PET, with and without MAH, has been determined. Addition of MAH reduced the density and impact strength and increased the tensile strength of blends. It has been found that at 3 N load the wear rate of PP/PET/MAH blends decrease. This reduction in wear rate at 3N load is due to the increased cross-linking created by the addition of small-size MAH. At 5 N load, abrasive wear rate reduced for PP/PET 95/5 and 90/10 blends on adding MAH. At 7 N load, wear rate of PP/PET(95/5) having MAH shows a reduction in wear rate compared to pure PP/PET blend. MAH addition on the wear rate of PP/PET blend at 7 N load shows that wear rate of PP/PET(95/5) blend for 6.4m sliding distance reduced from 3.85 × 10−10 to 3.38 × 10−10 m3/m. Wear rate, at 7 N load, for PP/PET(90/10) blend increased on adding MAH. Similarly, at 7 N load the PP/PET(80/20) and PP/PET(50/50) blends showed an increase in wear rate on adding MAH. Reversal of the wear rate trend from decrease to increase on adding MAH has been observed for more than 10 wt% blend at 7 N load. This can be explained based on the following two reasons: (a) at higher PET content, effective bonding between components of blends reduced and (b) higher loads would have increased the ploughing and cutting of the surface, which would have resulted in increased wear rate after 10 wt% PET loading. In the case of 50 PET loading, poor bonding of PP and PET was observed in worn surfaces. The majority of PET is present as second phase in the blend. In the case of PP/PET(50/50) blend, high wear rate is dominated by PET phase.