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1、中国科学技术大学硕士学位论文硅烷接枝/交联及膨胀型阻燃聚乙烯复合材料的制备与性能研究姓名：李明申请学位级别：硕士专业：高分子化学与物理指导教师：胡源20070501中国科学技术大学硕士学位论文摘 要本文在大量文献调研的基础上，针对硅烷接枝水交联技术在聚合物层状硅酸盐纳米复合材料这一领域中研究的不足，利用反应挤出法制备了硅烷接枝低密度聚乙烯蒙脱土纳米复合材料(LLDPEgVTMSOMT)，研究了制备过程中的插层机理和材料的力学性能以及热稳定性；利用熔融共混法制备了硅烷交联低密度聚乙烯氢氧化镁，蒙脱土(VTMSc-LLDPEMHOMT)纳米复合材料，研究了氢氧化镁和蒙脱土对交联聚乙烯阻燃性能和热稳
2、定性的影响；同时还着眼聚乙烯在阻燃性能方面存在的问题，从材料设计的理念出发，针对高密度聚乙烯蒙脱土(HDPEOMT)纳米复合材料使用乙烯一醋酸乙烯共聚物(EVA)作为相容剂的基体，设计了有不同成炭剂的膨胀阻燃体系，包括聚磷酸铵季戊四醇(APPPER)、聚磷酸铵尼龙(APPPA)和聚磷酸铵尼龙蒙脱土(APPnPA)对其阻燃性能和热稳定性进行了研究。运用x射线衍射(XRD)、透射电子显微镜(TEM)、傅立叶变换红外光谱(FTIR)和差示扫描量热分析(DSC)等表征了材料的结构并通过极限氧指数(LOI)、热重分析(TGA)、锥形量热计、材料实验仪等对材料的热性能、燃烧性能和力学性能等进行了评价。本文
3、得到以下有意义的研究结果：1采用反应挤出法制备了乙烯基三甲氧基硅烷接枝线性低密度聚乙烯(VTMSgLLDPE)OMT纳米复合材料。x射线衍射(XRD)和透射电镜(TEM)结果表明形成了典型的插层结构；红外光谱分析(FTIR)表明VTMS在蒙脱土片层上形成了化学键合，聚乙烯分子与蒙脱土片层通过化学键连接起来，形成LLDPEVTMSOMT一体结构，从而提高有机一无机组分之间的相容性，促进插层结构的形成；TOA结果证实LLDPEVTMSOMT一体结构的形成有助于提高材料热稳定性；力学性能测试结果证实在硅烷接枝聚乙烯体系中，蒙脱土具有更高的插层效率。2 采用熔融共混法制备了硅烷交联低密度聚乙烯，氢氧化
4、镁蒙脱土纳米复合材料(VTMS-c-LLDPEMHOMT)，着重考察了MH和OMT对硅烷交联线性低密度聚乙烯体系阻燃和热解性能的影响，并对其相关作用机理进行了探讨。中国科学技术大学硕士学位论文交联结构的形成有助于LLDPE基体力学性能、阻燃性能和热稳定性的提高，而MH和OMT的加入会阻碍LLDPE交联；LOI、TGA、锥形量热计、DSC结果表明，当使用同等份数的OMT替代了MH形成纳米复合材料之后，交联LLDPE体系没有出现预期中更为显著的各项性能的提高，反而有所下降。这说明OMrr的加入并不能与MH起到协效作用。3针对高密度聚乙烯蒙脱土(HDPEoMT)纳米复合材料使用乙烯一醋酸乙烯共聚物(
5、EVA)作为相容剂的基体，设计了有不同成炭剂的膨胀阻燃体系。在添加量为35时，只有APPPER体系达到了V-0级别；TGA、锥形量热计结果表明APPPER阻燃体系熔融过程较短且成炭较早；PERnPA体系的样品相比使用PERPA体系的氧指数有所提高，同时PHRR也有所降低，这可能是由于其中蒙脱土含量较高，覆盖层在材料表明堆积更均匀的原因。关键词：聚乙烯；蒙脱土；纳米复合；接枝；交联；膨胀阻燃中国科学技术大学硕士学位论文AbstractBased on the investigation ofa large amount ofliteratures，it is founded that artic
6、leson the study of the structure and properties on silane-grafted polymer based claynanocomposites ale tackingIn this dissertation，the silane-graftedlinear low densitypolyethyleneorganopbilic montmoriUonite(OMT)nanocomposite was prepared byreactive-extrusion，the intercalation mechanism，mechanical an
7、d thermal propertieswere studied；The silane-crosslinkedlinear low density polyethylenemagnesiumhydroxide(MH)OMT nanocompostics wefc prepared bY melt-bledndingtheinfluence of MH and OMT to fire safety and thermal properties were investigated；Meanwhile，in order to improve the flame retardancy of high
8、densitypolyethylenepolyethyleneCO-(vinyl acetate)OMT nanocomposite，ammoniumpolyphosphate(APP)accompanied with different charring agents,pentaerythritol(PER)，polyamide-6(PA)and PAOMT nanocomposite respectively as flame retardant，Wele investigatedThe morphology and pefformaces of the above mentionedma
9、terials were characterized bY Xray diffraction(XRD)，transmission electronmicroscope(TEM)，fouder transfer infrared spectroscopy(FTIR)，thermogravimetricanalyses frOA)，cone calorimetry,differential scanning calorimetry(DSC)，limitingoxygen index(LOI)，UL94 test and SO 0nThe important results have been ob
10、tainedas following：1The vinyltrimethoxysilane graRed linear low density polyethylene(VTMSgLLDPE)OMT nanocomposite has been prepared by reactiveextrusion，theXRD patterns and TEM images showed the formation of typical intercalatednanocomposite structure；TGA results indicated that the nanocomposite exh
11、ibitedhigher thermal oxidative stability；FTIR results indicated that the formation of thechemical bounds between LLDPE macromolecules and OMT surface facilitated theinteraction of polyethylene chains into clay interlays；Mechanical results showed thatOMT got hi曲er intercalation efficiency中国科学技术大学硕士学位
12、论文2The silanecrosslinkedlinear low density polyethylene(VTMS-eLLDPE)magnesium hydroxide(MH)OMT nanocomposties were prepared by melt-bledndingand investigatedThe formation of crosslinking structure was in favor of theenhancement of mechanical，flame retardant and thermal properties，however,MHcould hin
13、der the crosslinking of LLDPEResults indicated that the erosslinkednanocomposite showed lower thermal oxidative stability and fire safety than theVTMScLLDPEMH composite at the same additive level，the reason is postulatedto be that the incorporation of MH and OMT hinder the crosslinking of polyethyle
14、nemacromoleculars and crosslinking structure prevents the migration of OMT layers tothe surface,3 In order to improve the flame retardant properties of high densitypolyethyMnepolyethylene-co-(vinyl acetate)OMT mnocomposite,intumescentflame retardance(IFR)with different charring agents were designedI
15、t was found thatnanocomposites exhibited well values of LOl test when they were at loading 35，butonly PERAPP system could reach UL一舛V-O rating；TOA and cone calorimetryresults indicated that the sample which contained APPPER exhibited shorter meltingprocess and formed char earlier；The PERnPA containe
16、d sample showed higher LOIand lower PHRR value than the PERPA contained oneThe reason was postulated tobe that the clay-reinforced intumescent structure(PERAPP)is efficient in retardingbeat transfer and mass transportation,whereas the structure that clays mostlyaccumulated over sample surface(PERnPA)provides a further physical barrier inaddition to the intumescent barrierKeywords：Polyethy
