Preparation,Characterization And Properties Of PPO/UHMWRE Blends

PPO and UHMWPE are both widely used thermoplastic engineering plastics. PPO is equipped with high heat-resistance, rigidity, strength and excellent electrical properties. But its wear-resistance and toughness are poor. UHMWPE, however, has high wear-resistance,resistance to impact and corrosion but low heat-resistance, rigidity and hardness. Application of PPO and UHMWPE are limited in their respective fields due to their different material properties. This study aims to maintain the basic properties of PPO and improve the wear-resistance and toughness of PPO by blending UHMWPE with it.PS grafted onto UHMWPE(UHMWPE-g-PS) was synthesized by suspension grafting copolymerization technique with pre-irradiated UHMWPE by an electron accelerator in air.By optimizing the experimental conditions, the graft copolymer with 18% grafting degree was prepared. The chemical structure and properties of the graft copolymer were studied using FTIR, 1H-NMR, and SEM. In this article, PPO/UHMWPE-g-PS/UHMWPE blends with various weight ratios were prepared by melt blending, using UHMWPE-g-PS as a compatibilizer. The blends are divided into four blending systems: 70% PPO, 80% PPO,90% PPO, and 95% PPO, respectively.Thermal properties, mechanical properties, wear and friction properties and morphologies were investigated. DSC indicated that with the increasing of the content of graft copolymer, the melting temperature of PPO/UHMWPE-g-PS/UHMWPE blends rose gradually, and the compatibilization was getting better and better. The morphology of the fractured surfaces also confirmed that. Tensile strength, flexural strength and hardness of the four blending systems also increased obviously with the increasing of graft copolymer.Toughness of the blends was improved significantly by addition of UHMWPE. The best mechanical properties was achieved at 95/5/0 blending ratio.It is evident that the properties of modified PPO blends are significantly improved in tribological aspects based on friction and wear data. For 95% and 90% PPO blending systems, tribological parameters were better than those of UHMWPE except for the wear volume. The wear volume of the blend reached to 2.6% of that of PPO at weight ratio of 95/5/0, and the friction coefficient was reduced by55%.Considering the entire performance of the blending systems,PPO/UHMWPE-g-PS/UHMWPE(95/5/0)blend is optimal. At this blending ratio, tensile strength, flexural strength, and Rockwell hardness are 66.4 MPa, 98.6 MPa, and 114.1 HRL,the impacting specimens did not break. Meanwhile wear volume and wear coefficient are0.006 cm~3 and 0.195.