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1、哈尔滨理工大学学士学位论文TiO2改性热固性PI的合成及介电性能研究摘要聚酰亚胺(PI)是以酰亚胺环为结构特征的一种杂环聚合物。其制品尺寸稳定性好、耐有机溶剂、低温性能优良、高温下介电、力学、耐腐蚀等性能突出,是目前综合性能最好、耐热等级最高的一种性能优异的工程材料。纳米二氧化钛具有较好的热稳定性、化学稳定性和优良的电学特性,可以提高材料耐老化性能及耐高温性能,故选用它们作为填料进行表面处理后添加到聚酰亚胺中去,通过一定的成膜工艺制备成膜,可以提高了PI的耐电压寿命。本文选用DEDADPM为二胺单体、均苯四甲
2、酸二酐为二酐单体、纳迪克酸酐为封端剂、DMAc为溶剂以两步法合成热固性聚酰亚胺;期间以KH560为偶联剂改性的二氧化钛为掺杂粒子以原位聚合法制备TiO2/PI复合材料。利用原子力显微镜(AFM)和扫描电子显微镜(SEM)对复合材料的断面形貌进行了分析,并对复合材料的热力学性能和介电性能进行了测试和分析。结果表明:无机粒子均匀的分散在有机基体中,随着纳米TiO2质量分数增加,其热分解温度呈单调上升趋势;其介电常数和介电损耗也都呈上升趋势。关键词 热固性聚酰亚胺;原位聚合;TiO2;介电性能-III-哈尔滨理工大
3、学学士学位论文SynthesisandStudyondielectricpropertiesofthermosettingpolyimidemodifiedbyTiO2AbstractPolyimide(PI)isdefinedasakindofheterocyclicpolymerswithimideringstructure.Itsproductsowngooddimensionalstability,resistancetoorganicsolvents,wellperformanceatlowtemp
4、erature,hightemperaturedielectric,mechanical,corrosionandotheroutstandingperformance,whichcurrentlygivethebestoverallperformanceandthehighestlevelofintegratedheatresistivitythatknownasengineeringmaterials.Nanostructuredtitaniumdioxidehasbetterthermalstabili
5、ty,chemicalstabilityandexcellentelectricalproperties,notonlyimprovethepropertiesofagingresistanceandhightemperatureresistivity,butalsothermalexpansioncoefficientinaccordancewithpolyimidematch,soareusedasfillerswithprevioussurfacemodification,thenaddedtothep
6、olyimide.Furthermore,somefilmsarepreparedbyfilm-formingprocesswithpolyimide,whichincreasethevoltageresistancelifeofPI.Inthisarticle,thermosettingpolyimideispreparedviatwostepsinthepresenceofDEDADPMasmonomer,pyromelliticdianhydrideasdianhydridemonomer,NadiKe
7、anhydrideascappingagent,DMACasthesolvent;duringthecourse,nanostructuredtitaniumdioxidewhichfunctionsasdopingparticlesaremodifiedbytheSilonecouplingagentofKH-550,thenusedtopolymerizeTiO2/PIcomposites.Atomicforcemicroscopy(AFM)andscanningelectronmicroscopy(SE
8、M)areusedtoanalyzefracturemorphologyofthecomposite,andtestsrelatedtothermodynamicanddielectricpropertiesofcompositematerialsarealsoconducted.Theresultsshowedthat:inorganicparticlesevenlydispersedinorga