High abrasive wear resistance polyethylene blends: an adapted Ratner–Lancaster correlation

Abstract

Ultra-high molecular weight polyethylene (UHMWPE) is one of the polymers with the best abrasive wear performance that exists, being used in engineering applications where this property is required. Despite its excellent property, UHMWPE still performs poorly in many applications. Therefore, the development of new materials with better properties is always very desirable. In this study, it is presented for the first time that it is possible to obtain polyethylene blends with better wear performance than UHMWPE. Linear polyethylenes, high-density polyethylene (HDPE), high molecular weight polyethylene (HMWPE) and UHMWPE, and blends, HMWPE-UHMWPE (10, 20 and 40 wt%), and HDPE-UHMWPE (20 and 40 wt%), have been studied here. The study was developed based on the correlation between the tensile test and the wear test of these materials. In 1968, Lancaster suggested that the abrasive wear resistance of polymers is strongly related to the product between the stress and strain at breaking obtained from the tensile test. This correlation is known as the Ratner–Lancaster correlation. Although this correlation is suitable for many polymers, it is not suitable for all. HDPE, HMWPE, and UHMWPE are examples of polymers where this correlation is not suitable. With the knowledge that the amorphous phase of polymers is responsible for wear resistance and ultimate tensile properties, a new and more suitable correlation for linear polyethylenes is suggested in this study. This correlation shows that the hardening modulus must be included as a factor to predict the abrasive wear resistance. The blends of HMWPE containing 10 and 20 wt% of UHMWPE showed volumetric loss after the wear test of 47.0 and 45.2 mm3, respectively, while UHMWPE presented a higher volumetric loss, of 55.7 mm3. The excellent performance of the blends was possibly due to a better understanding of the correlation between the tensile and abrasive tests proposed in this study.