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1、[Article]doi:10.3866/PKU.WHXB201411062www.whxb.pku.edu.cn乙?；幚韺A木質(zhì)素在四氫呋喃中微結(jié)構(gòu)的影響李浩鄧永紅*邱學(xué)青*(華南理工大學(xué)化學(xué)與化工學(xué)院,制漿造紙工程國家重點(diǎn)實(shí)驗(yàn)室,廣州510640)摘要:通過對比堿木質(zhì)素(AL)和乙?；瘔A木質(zhì)素(ACAL)在四氫呋喃(THF)中溶液行為和物理化學(xué)性質(zhì)的差異,揭示了乙酰化處理對堿木質(zhì)素在THF中微結(jié)構(gòu)的影響.分別采用動態(tài)光散射、凝膠滲透色譜(GPC)、透射電子顯微鏡(TEM)、特性粘度、熒光光
2、譜儀、耗散型石英晶體微天平(QCM-D)和自組裝技術(shù)等研究了AL和ACAL在聚集形態(tài)、聚集機(jī)理以及吸附特性等方面的特征.研究發(fā)現(xiàn),乙?；幚頃档蛪A木質(zhì)素在THF中的分子間和分子內(nèi)聚集程度.AL在THF中以單分子和聚集體的形式共同存在,分子較為蜷曲;ACAL在THF中則更多地是以單分子形式存在而幾乎不存在大聚集體,分子較為伸展,其流體力學(xué)半徑要比相同絕對分子量的AL更大.THF中的AL聚集體會在液固界面上發(fā)生強(qiáng)烈的吸附,但ACAL由于與溶劑間的相互作用較強(qiáng)而幾乎不會吸附在液固界面上.由于AL分子
3、在THF中較為蜷曲且吸附能力較強(qiáng),因此利用以THF為流動相的GPC直接測量AL的分子量時(shí)所得結(jié)果并不準(zhǔn)確,為保證GPC的測量結(jié)果更加全面可靠,需要在測量前對堿木質(zhì)素進(jìn)行乙?；幚?關(guān)鍵詞:堿木質(zhì)素;乙?；?微結(jié)構(gòu);聚集;分子量中圖分類號:O647;O648InfluenceofAcetylationontheMicrostructureofAlkaliLignininTetrahydrofuranLIHaoDENGYong-Hong*QIUXue-Qing*(StateKeyLaboratory
4、ofPulpandPaperEngineering,SchoolofChemistryandChemicalEngineering,SouthChinaUniversityofTechnology,Guangzhou510640,P.R.China)Abstract:Theeffectofacetylationonthemicrostructureofalkalilignin(AL)intetrahydrofuran(THF)wasstudied.Thephysicochemicalproper
5、tiesofALandacetylatedalkalilignin(ACAL)werecompared.Dynamiclightscattering,gelpenetrationchromatography(GPC),transmissionelectronmicroscopy(TEM),intrinsicviscosity,fluorescencespectrophotometry,quartzcrystalmicrobalancewithdissipation(QCM-D)measureme
6、nts,andlayer-by-layer(LbL)self-assemblywereusedtoinvestigatetheaggregationandadsorptionofALandACAL.IntermolecularandintramolecularassociationsinALdecreasedfollowingacetylation.ALinTHFexistedmainlyasmono-moleculesandintermolecularassociationsandhadamo
7、recompactconformation.ACALexistedmainlyasmono-moleculeswithamorestretchedconformation.ACALhadalargerhydrodynamicradiusthanAL(ofthesameabsolutemolecularmass),becauseofitsstretchedconformation.QCM-DandLbLself-assemblymeasurementssuggestedthatALaggregat
8、eshaveastrongtendencytoadsorbattheliquid-solidinterface,butACALhardlyadsorbatthisinterfacebecauseofitsstrongerinteractionwithTHF.ThecompactconformationandstrongadsorptionpropertyofALresultedininaccuratemolecularweightsofnon-acetylatedAL,asmeasuredbyG
