PVC新型稀土热稳定剂的合成与应用研究

论文题目：PVC新型稀土热稳定剂的合成与应用研究专业：应用化学硕士生：丁贺(签名)导师：李侃社(签名)摘要近年来PVC行业得到迅速发展，因而PVC热稳定剂也成为重要产业。为防止PVC在加工过程中分解，热稳定剂是必不可少的添加剂。目前，铅盐类稳定剂在我国占主导地位。随着人们环保意识的逐渐增强，铅盐等重金属盐类稳定剂逐步被淘汰，无毒高效复合的稳定剂成为研究的热点。稀土化合物热稳定剂是一种新型的PVC热稳定剂，稀土稳定剂因其具有无毒、高效、多功能、价格适宜等优点，适用于多种PVC制品。我国稀土资源丰富，充分利用我国的稀土资源优势，开发适合我国国情的PVC热稳定剂具有很大的现实意义。本文合成了一种新型的稀土化合物：马来酰胺酸稀土，并作为PVC热稳定剂。经实验确定合成马来酰胺酸稀土的影响因素主要有氢氧化钠浓度，氯化稀土浓度，pH值和反应时间，并通过正交实验确定了昀佳合成工艺条件。通过元素分析和热重分析，确定马来酰胺酸稀土的分子式；通过红外光谱、紫外光谱和核磁共振氢谱等进一步分析，得出马来酰胺酸稀土的配位方式。通过静态法和动态法测试马来酰胺酸稀土对PVC的热稳定性，得出四种马来酰胺酸稀土对PVC的稳定作用依次为：LaL3＞DyL3＞YL3＞SmL3。与传统无毒热稳定剂相比，马来酰胺酸稀土稳定剂略差于有机锡，而优于直链脂肪酸稀土和其他稳定剂。通过马来酰胺酸稀土与其他热稳定剂协同效应研究表明，马来酰胺酸稀土与硬脂酸钙、有机锡、季戊四醇存在良好的协同效应。通过红外光谱分析，推测马来酰胺酸稀土的稳定机理为：稀土元素具有未被电子填充满的4f、5d和6s空轨道，且具有较大的原子半径，能够形成较多的配位数，因此容易与PVC中不稳定的氯原子配位成键从而对PVC起到稳定作用。制备了稀土复合稳定剂，经测试稀土复合稳定剂具有良好的热稳定性能，并且使用稀土复合稳定剂的PVC制品具有良好的力学性能。关键词：聚氯乙烯；马来酰胺酸稀土；热稳定剂；协同效应研究类型：应用研究Title:StudyontheSynthesisandApplicationofRare-earthasNewThermalStabilizerforPVCDiscipline:AppliedChemistryName:DingHe(Signature)Advisor:LiKanshe(Signature)ABSTRACTPoly(vinylchloride)tradeisobtainedtodeveloprapidlyinrecentyearsinChina.Therefore,thethermalstabilizersforPVCbecomemoreimportant.ItisnecessarytoaddsomethermalstabilizertopreventorretardPVCfromdegradation.Atpresent,toxicleadstabilizersarewidelyused.Withincreasinghealthconsciousness,theleadsaltsstabilizersmustbeforbiddengraduallyinfuture,andnon-toxicefficientandcompositethermalstabilizersarefocusedondevelopment.Rare-earthcompoundstabilizerisanewkindofPVCthermalstabilizer.Rare-earthcompoundstabilizerisfitformanyPVCproductbecauseofnon-toxicity,efficiency,functionalityandeconomyetc.Therare-earthresourceisabundantinChina.Soitisgreatlysignificanttoutilizetherare-earthresourceanddevelopPVCthermalstabilizerswhicharefitourcountry.Anewkindofrare-earthcompoundasPVCthermalstabilizerwassynthesizedinthepaper,rare-earthmaleicanilineacidsalt.Basedonexperimentsfourkindsofrare-earthmaleicanilineacidsaltweresynthesized,theinfluencingfactorssuchastheconcentrationofNaOH,theconcentrationofRECl3,pHandreactiontimewereinvestigated.Withthedateoforthogonaltest,thepreferablesyntheticconditionswerefound.Themolecularformulasofrare-earthmaleicanilineacidsaltwereconfirmedbyTGandelementanalysis.AndthecoordinationmodewasconfirmedbyFTIR,UVandH1NMRanalysis.Thethermalstabilitiesofthesefourrare-earthmaleicanilineacidsaltswereresearchedthroughstaticanddynamicmethods.TheirorderofstabilityisLaL3DyL3YL3SmL3.Comparedwithtraditionalthermalstabilizers,thestabilityofrare-earthmaleicanilineacidsaltsisbetterthanrare-earthstraightchainfattyacidsaltsandotherstabilizers,andalittlelowerthanorganictinstabilizer.Thesynergisticeffectsoftherare-earthmaleicanilineacidsaltswithotherstabilizerswerealsodiscussed.Theresultsshowedthattherare-earthmaleicanilineacidsaltswerewellsynergisticwithCaSt,organictinandpentaerythritol.ThemechanismofstabilizationforPVCisconjecturedbyFTIRanalysis.Becausetheelectronshellstructureofrare-earthwithempty4f,5dand6sorbits,itcanreactcoordinatelywithlabilechlorineatomseasilyinPVCchainswhentheyareintheheatedprocess,anditcanalsoabsorbdehydrochlorination.Basedonexperimentsrare-earthcompositethermalstabilizerwasprepared.Andthestabilityandmechanicsperformancewerepromotedevidentlybytherare-earthcompositethermalstabilizer.Keywords:PVCrare-earthmaleicanilineacidsaltsstabilizersynergisticeffectThesis:Applicationresearch目录I目录1绪论........................................................................................................................................11.1PVC降解和稳定机理......................................................................................................11.1.1PVC分子的结构.......................................................................................................11.1.2PVC分子的结构缺陷...............................................................................................21.1.3PVC不稳定的其他因素...........................................................................................31.1.4PVC降解机理...........................................................................................................41.2热稳定机理......................................................................................................................61.3热稳定剂概述..................................................................................................................71.3.1铅盐稳定剂...............................................................................................................71.3.2金属皂复合稳定剂...................................................................................................71.3.3有机锡热稳定剂.......................................................................................................81.3.4有机锑热稳定剂.......................................................................................................81.3.5有机和辅助热稳定剂...............................................................................................91.3.6稀土热稳定剂...........................................................................................................91.4热稳定剂的国内外概况...........