Toughened And Flame-retardant Modification Of Poly(4-methyl-1-pentene)

Isotactic poly(4-methyl-1-pentene)(PMP) is a kind of extremely potential applications ofnew polyolefin materials, which has a number of better properties such as high meltingtemperature, low dielectric constant, high transparency and mechanical properties than otherpolyolefin materials. But as a competitor of fluorine plastic using in high temperature and highfrequency signal transmission cable, its flexibility and toughness is deficient. In this thesis, thetoughening and flame retardance of PMP were studied by blending method systematicly.1. In order to analyze the isothermal crystallization kinetics, non-isothermal crystallizationkinetics and the changes of the mechanical properties of the PMP/PP blend, different proportionsof PMP/PP blend were prepared. The result shows that PMP and PP will have influence on eachother’s crystallizaiton, and no obvious phase separation were found on fracture surfaces. So thereis compatibility between PMP and PP to some extent, the modification of PP can be referenced inPMP toughening and flame retardant modification research.2. In the study of mechanical properties, thermal properties and morphology of fracturesurface of PMP/elastomers (EPDM, POE, SBS), we can find PMP/EPDM and PMP/POE blendshave better impact strength, whereas PMP/SBS blends have the best elongation at break of35.33%. There is obvious phase separation between PMP and elastomers. In DSC analysis, POEand EPDM facilitates the crystallization of PMP, but the big side group of SBS hinders regulararrangement of PMP molecular chains. This has bad effect on mechanical properties and resultedin lower crystallinity.3. For the modification of PMP with different contents of SBS,10%SBS has betterproperties, its elongation at break reaches35.33%and impact strength reaches46.9J/m. With theincreasing content of SBS, its elongation at break decreases dramatically and has bad effect onapplications.4. The ternary blend and crosslinking method can improve the PMP/SBS blendcomprehensive performance. PMP/PP/SBS ternary blend has better comprehensive performance,PP in the blend have the effect of compatilizer, at the same time improve the rigidity and strengthof blend; DCP crosslinking PMP/SBS blend has a higher flexibility, elongation at break can beup to113.33%, but the rigidity and strength will be decreased.5. There has great differences between DIPE and PEPA modifications of PMP. Considering flame retardant and mechanical properties, DIPE is more fit in PMP modification as carbonificcompounded with MPP. When MPP:DIPE reaches3:1, LOI could reach32.4%and VerticalBurning Test could reach UL94V-0Grade.6. MPP compounded with DIPE in3:1can be used as IFR, the more content of IFR, thebetter flame retardant properties PMP will have. When IFR become more than30%, LOI canreach32.4%, Vertical Burning Test can reach UL94V-0Grade and the carbon yield is higherthan other samples which reaches14.44%. Mechanical properties of the blends become worsewith IFR and this may relate with the poor compatibility between PMP and IFR.7. By adding5%of PP-MAH and A-172to improve compatibility between PMP and flameretardant, impact performance and the elongation at break were obviously improved, the impactstrength of the A-172modified flame retardant PMP is115.65J/m, up212%. But as a result ofthe existence of small molecules, rigidity and strength of the blends slightly decrease. At thesame time, the LOI dropped to29.2%, vertical combustion performance is also reduced.