Dissertation
Dissertation > Industrial Technology > Chemical Industry > Synthetic resins and plastics industry > General issues > Basic theory

Study the Composites of Rare Earth β-Nucleating Agent/POM/EVA/Polypropylene

Author NieZuo
Tutor DingHuiLi
School Hebei University of Technology
Course Polymer Chemistry and Physics
Keywords polypropylene rare-earthβ-nucleating agent polyoxymethylene ethylene/vinyl acetate composite material mechanical properties crystallization properties
CLC TQ320.1
Type Master's thesis
Year 2011
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In this study, rare earthβ-nucleating agent (WBGⅡ), polyoxymethylene (POM) and Ethylene/vinyl acetate(EVA) are used to modify ethylene-propylene random copolymer(PPR). The effect of WBGⅡ, POM andEVA on the mechanical properties, thermal performance and crystallization properties of the composite werediscussed 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 EVAcan 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 ofWBGⅡ/POM/EVA/PPR equals 0.5/3/15/100. The tensile and flexural properties of modified PPR onlydecrease 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 showsthat both WBGⅡand POM can induceβ-crystal modification in PPR, they change crystalline morphology ofPPR from spherulite shapedα-crystal to acicular shapedβ-crystal. WBGⅡand POM both increase the amountof crystallization center, accelerate the crystallization rate and make the size of crystal much smaller. As aelastomer, EVAcan improve the impact strength significantly.The TG test shows the modified PPR has good thermal stability. The DMA test results indicate that modifiedPPR has fine compatibility.The melting temperature and crystallization temperature of PPR has been improved by the addition ofWBGⅡand POM.

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