稀土b成核剂plmevapp复合材料的研究-study on plmewvapp composite with rare earth b nucleating agent.docx

稀土β成核剂/POM/EVA/PP 复合材料的研究 Study on the Composites of Rare Earth β-Nucleating Agent/POM/EVA/Polypropylene ABSTRACT In this study, rare earth β-nucleating agent (WBGⅡ), polyoxymethylene (POM) and Ethylene/vinyl acetate (EVA) are used to modify ethylene-propylene random copolymer(PPR). The effect of WBGⅡ, POM and EVA on the mechanical properties, thermal performance and crystallization properties of the composite were discussed by the means of mechanical properties tests, TGA, DMA, PLM, DSC and SEM. And it shows that: By adding certain amount of WBGⅡ, POM and EVA can improve the impact strength of PPR significantly. The impact strength of modified PPR changes from 10.3 KJ/m2 to 15.4 KJ/m2, 1.5 times higher than neat PPR, and the elongation at break changes from 91.5% to 287.3%, 4 times higher than neat PPR, when the ratio of WBGⅡ/POM/EVA/PPR equals 0.5/3/15/100. The tensile and flexural properties of modified PPR only decrease a small amount, the mechanical properties of the composites is improved obviously. The crystallization properties of modified PPR was discussed by means of PLM, WAXD and DSC. It shows that both WBGⅡ and POM can induce β-crystal modification in PPR, they change crystalline morphology of PPR from spherulite shaped α-crystal to acicular shaped β-crystal. WBGⅡand POM both increase the amount of crystallization center, accelerate the crystallization rate and make the size of crystal much smaller. As a elastomer, EVA can improve the impact strength significantly. The TG test shows the modified PPR has good thermal stability. The DMA test results indicate that modified PPR has fine compatibility. The melting temperature and crystallization temperature of PPR has been improved by the addition of WBGⅡ and POM. Key words: polypropylene, rare-earth β-nucleating agent, polyoxymethylene, ethylene/vinyl acetate, composite material, mechanical properties, crystallization properties ii  原创性声明 本人郑重 ):-i H)J : 用7 甲欠的学价论立 ，是本人在导师指导下