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1、冠『」匕」二山_气习刁子【d匕:岁=t立士仑j忆摘要本文选择不同种类聚乙烯(PE)作为基体树脂,过氧化二异丙苯(DCP)作为引发剂,乙烯基三乙氧基硅烷(VTES)作为接枝单体,二月桂酸二丁基锡(DBTDL)作为催化剂,在双螺杆挤出机中进行了二步法硅烷交联聚乙烯的研究。讨论了PE种类、DCP和VTES含量以及交联温度、时间、螺杆转速等工艺条件对交联料的性能影响规律,研制出了综合性能优异的硅烷交联聚乙烯产品,并实际用于铝塑复合热水管中。在此基础上,比较系统地研究了纳米蒙脱土(n-MMT)对硅烷交联聚乙烯的改性。探讨了母料法、
2、直接共混法和溶液法三种n-MMT的分散方法,采用透射电子显微镜(TEM)、扫描电子显微镜(SEM)和X射线衍射(XRD)等手段表征了n-MMT在聚合物中的分散、插层状态,采用差示钾描量热法(DSC)研究了n-MMT对PE结晶行为的影响,研究了蒙脱土含量对硅烷接枝聚乙烯的性能影响。结果表明采用聚乙烯接枝马来酸配(PE-g-MAH)作为载体树脂,先在双螺杆挤出机中制备纳米蒙脱土母料,再与硅烷接枝聚乙烯共混挤出制备硅烷接枝聚乙烯/蒙脱土纳米复合材料是一种可行的方法,能够实现PE分子链向蒙脱土的层间插层,并使接枝料的热稳定性、屈
3、服强度、屈服模量提高,但使接枝料的断裂延伸率和交联料的交联度下降。当n-MMT含量为3-5%(质量百分比)之间,硅烷接枝聚乙烯/蒙脱土复合材料的综合性能较好。关键词:硅烷交联聚乙烯纳米蒙脱土插层复合材料a耳」匕口二J匕二气习斑d二州二七2i2二弋恤界AbstractWithdicumylperoxide(DCP)asinitiator,vinyltriethoxysilane(VTES)asmonomer,dibutyltindilaurate(DBTDL)ascatalyst,thethesischoosesdifer
4、entPolyethylene(PE)tostudysalinecross-linkingofpolyethylene(PEX)inthetwo-screwextruder.TheefectsoftechnicsonthepropertiesofPEXwerestudied,suchasthekindofPE,thedosageofDCPandVTES,cross-linkingreactiontimeandtemperature,screwrotationalspeed.PEXhasgoodperformancesan
5、dhasbeenusedtoproductionofthealuminum-plasticscompoundpipealready.4nthebasisofaboveresearch,nano-montmorillonite(n-MMT)modifiedPEXwasstudied.Threedispersedmethodswasinvestigated,theyaremeltblendingintercalation,mastbatchintercalationandsolutionintercalation.Thest
6、ructureofn-MMTinthepolymermatrixwasstudiedbymeansofTEM,SEM,XRD.Theefectofn-MMTtocrystallinityofPEbyDSCandthecontentofn-MMTinmatrixtothepropertiesofPEXmatrixwasstudied.TheresultshowedthatPEX/MMTnanocompositewaspreparedthroughmastbatchintercalationisafeasiblemethod
7、andn-MMTcanbeintercalatedbymoleculechainofPE.ThismethodusePEgraftedMAHascarrierresintopreparen-MMTmastbatchinthetwo-screwextruder.MastbatchmeltwithPEgraftedVTESandpreparePEXIMMTnanocompositeinthetwo-screwextruder.ComparedwithPEX,PEgraftedVTESmatrixhasbeter如eldstr
8、ength,yieldmodule,heatstability,andworseelongationrate,thegelfractionofPEXmatrixdecrease.Whenthecontentofn-MMTbetween3%to5%,PEX/MMTnanocompositehasbeterpropert