含马来酸酐的活性四嵌段共聚物用于增韧环氧

Improvingthetoughnessofepoxywithareactivetetrablockcopolymercontainingmaleicanhydride含马来酸酐的活性四嵌段共聚物用于增韧环氧ABSTRACT:Reactiveblockcopolymers(BCPs)provideauniquemeansfortougheningepoxythermosetsbecausecovalentlinkagesprovideopportunitiesforgreaterimprovementinthefracturetoughness(KIC).活性的嵌段共聚物（BCPs）提供了一种独特的增韧热固性环氧材料的方法，因为其共价键对热固性材料的断裂韧性（KIC）有很大的提高。Inthisstudy,atailoredreactivetetrablockcopolymer,poly[styrene-alt-(maleicanhydride)]-block-polystyrene-block-poly(n-butylacrylate)-block-polystyrene,wasincorporatedintoadiglycidyletherofbisphenolAbasedepoxyresin.在本文中，一种定制的四嵌段共聚物，聚[苯乙烯-alt-（顺丁烯二酸酐）]-混-聚苯乙烯-混-聚丙烯酸正丁酯-混-聚苯乙烯，被插入二缩水甘油醚双酚A环氧树脂。TheresultsdemonstratetheadvantageofreactiveBCPinfinelytuningandcontrollingthestructureofepoxyblends,evenwith95wt%epoxy-immiscibletriblocks.结果表明活性BCP能很好地调节和控制环氧混合物的结构，甚至可以加入95wt%的与环氧不相溶的四嵌段化合物。Thesizeofthedispersedphasewasefficientlyreducedtosubmicrometerlevel.分散相的尺寸可以有效地减至亚微米水平。Themechanicalproperties,suchasKIC,ofthesecuredblendswereinvestigated.本文还研究了其固化体系的机械性能，如断裂韧性KIC。Theadditionof10wt%reactiveBCPintotheepoxyresinsledtoconsiderableimprovementsinthetoughness,impartingnearlya70%increaseinKIC.给环氧树脂中加入10wt%的活性BCP就可以大幅度地提高其韧性，其相应的KIC也可以提高70%左右。Thedesignedreactivetetrablockcopolymeropenedgoodprospectsbecauseofitspotentialnovelapplicationsintougheningmodificationofengineeringpolymercomposites.VC2015WileyPeriodicals,Inc.J.Appl.Polym.Sci.2016,133,42826.这种设计的活性四嵌段共聚物打开了一个美好的前景，因为其在工程聚合物材料的韧性改性中有相当大的潜力。INTRODUCTION简介Epoxyresinshavebeenwidelyappliedasmatricesofadhesivesandstructuralmaterialsbecauseoftheirhighlycrosslinkednature.环氧树脂以其高的交联性质被广泛地应用于胶黏剂和结构材料。Thisfeaturealsobringscertaindrawbacks,includingbrittlenessandnotchsensitivity.这种特性依然有它的缺点，包括脆性和易断性[1]。Toexpandtheirapplications,thetougheningmodificationofepoxyresinshasattractedresearcher’sattentionformanyyears.为了拓展它们的应用领域，对环氧树脂韧性的改性已经被研究很多年了[2–10]。Recently,ithasbeendemonstratedthattheincorporationofblockcopolymers(BCPs)ismuchmoreefficientattougheningbrittleepoxyther-mosets.近来，加入嵌段共聚物可以有效地增韧脆性的热固性环氧已经被证明了[11–19]。Unlikeoligomericorcoreshellrubberinclusions,BCPsareeffectiveatlowloadingswithoutsignificantsacrificesofthemodulusorglass-transitiontemperature(Tg)ofthethermosets.不像低聚物或者次微米级橡胶夹杂物，BCPs不会以大幅降低热固性材料的模量和Tgs作为代价的[20]。ThemainconceptofBCPsinmodifyingepoxyblendsistheirmiscibilityinepoxyblends.BCPs改性环氧的主要问题就是它们与环氧混合物的可混溶性。Togeneratenanostructuredthermosets,atleastoneepoxy-miscibleblockandoneepoxy-immiscibleblockmustbeintroducedintotheseBCPs.16,19,21–26为了形成纳米结构的热固性材料，至少要使得环氧可溶性的颗粒和环氧不溶性的颗粒都可以被引进BCPs[16,19,21–26]。InthecaseswheretheBCPdoesnothaveanysegmentsmisciblewiththeepoxyresin,itisessentialtochemicallymodifyoneoftheblockstomakeitmisciblewiththeepoxyresin.8,19当BCP中没有可以和环氧混溶的片段的时候，就必须使用化学的方法对其进行改性，使其可以和环氧树脂混溶[8.19]。Batesetal.27foundthatepoxygroupsinthereactiveBCPspoly(epoxyisoprene)-block-polybutadieneandpoly(methylacrylate-co-glycidylmethacrylate)-block-polyisoprenewereabletoreactwiththeamineendgroupsofthehardener.Batesetal.[27]发现在活性BCPs聚（环氧异戊二烯）-混-聚丁二烯和聚（丙烯酸甲酯-共-甲基丙烯酸缩水甘油酯）-混-聚异戊二烯中，可以和端氨基固化剂反应。ThesereactiveBCPscouldcureintheepoxynetworkwithoutmacrophaseseparation.这些活性BCPs可以在环氧体系中固化，且没有宏观的相分离。Toimprovethecompatibilitybetweencommercialelastomersandepoxyresins,thedoublebondsinpolystyrene-block-poly(n-butylacrylate)-block-polystyrenewereepoxidizedtobereactive;thus,long-rangeorderednanostructuresinepoxidizedpolystyrene-block-poly(n-butylacrylate)-block-polystyrene/diglycidyletherofbisphenolA(DGEBA)blendscuredwith4,40-diaminodiphenylmethane(DDM)wereachieved.28–30提高商业弹性体和环氧树脂的混溶性，聚苯乙烯-混-聚（n-丙烯酸丁酯）-混-聚苯乙烯中的双键就可以被环氧化；从而，环氧化聚苯乙烯-混-聚（n-丙烯酸丁酯）-混-聚苯乙烯/二缩水甘油醚双酚A（DGEBA）混合物的（4,4-二氨基二苯基甲烷）DDM固化物的长程有序纳米结构就可以得到。Inpreviousstudies,thereactivegroupsintroducedintotheBCPswerenotabletoreactwithDGEBAorwererandomlydistributed.18,27,31在先前的研究中，BCPs中的活性集团是不能和DGEBA反应的或者只是随机地分散在DGEBA中[18,27,31]。ThiswasbecausethemostofcommercialBCPswerepreparedthroughanionicpolymerization;thismadeitdifficult,bydefinition,tointroduceawidevarietyofreactivegroupsonaccountofundesirableterminations.27,31,32这是因为大多数的商用BCPs都是用阴离子聚合的方法生产的；这当然地使得它很难再接入一个不受欢迎的活性端基基团[27,31,32],Inrecentyears,withtheadvancesofcontrolledradicalpolymerization,reversibleaddition–fragmentationchain-transferpolymerizationcanbeeasilyappliedtothepreparationofamphiphilicBCPsoverawidetemperaturerangebecauseofitsfunctionalgrouptolerance.33,34近年来，随着可控自由基聚合的发展，由于其功能性基团的容忍性，可逆地增加碎片进行链转移聚合可以很容易地应用到在很宽的温度范围内制备两亲性的BCPs[33,34]。Throughthismethod,alotofinnovativeBCPselastomerscomposedofsoftandhardsegmentswithinterestingpropertieshavebeenconvenientlysynthesized.通过这种方法，一大批的由软链和硬链合成的，具有特殊性能的新型BCPs弹性体可以被很方便地制备出来。Ithasbeenreportedthatmaleicanhydridecontainingcopolymersimprovetheinterfacialcompatibilitybetweenepoxy-immiscibleelastomersandtheepoxymatrix.35有报道称，含有顺丁烯二酸酐的共聚物可以提高环氧不相溶性的弹性体和环氧基体的界面相溶性[35]。Inourpriorwork,thetetrablockcopolymerpoly[styrene-alt-(maleicanhydride)]-block-poly-styrene-block-poly(n-butylacrylate)-block-polystyrene(SMA–SBAS)wassuccessfullyobtained.在我们先前的工作中，一种四嵌段共聚物聚（苯乙烯-共-（顺丁烯二酸酐））-混-聚苯乙烯（SMA-SBAS）被成功地制备了出来。However,theef