資源描述:
《羥丙基甲基纖維素的乳液接枝共聚合》由會員上傳分享,免費在線閱讀,更多相關(guān)內(nèi)容在學術(shù)論文-天天文庫。
1、中文摘要在水介質(zhì)中,以過硫酸鉀(KPS)引發(fā)丙烯酸乙酯(EA)與羥丙基甲基纖維素(HPMC)的接枝共聚合,反應(yīng)歷程與經(jīng)典乳液聚合相似??疾炝朔磻?yīng)溫度、單體濃度、預(yù)接觸時間、鏈轉(zhuǎn)移劑異丙醇(IPA)等對接枝率、接枝效率的影響。接枝率在反應(yīng)溫度為65℃時達到最大,而隨反應(yīng)溫度升高,接枝效率始終是降低的;延長KPS與HPMC的預(yù)接觸時間、提高單體濃度有利于提高接枝率與接枝效率;引入鏈轉(zhuǎn)移劑IPA會降低接枝率與接枝效率,但有助于得到穩(wěn)定的高固含量的乳液。采用IR、DSC對接枝共聚物進行了表征。在DSC譜圖上,HPMC與PEA的玻璃化溫度(T。)相互靠近,表明其相容性提高,接枝共聚物HPMC.g
2、.PEA是兩者的增容劑。當接枝率較低時,材料的相容性較差,其力學性能也較差。引入功能性含胺單體甲基丙烯酸二甲氨基乙酯(DM)參與接枝共聚,可以賦予產(chǎn)物在酸性介質(zhì)中溶解的性能,但也會降低單體的轉(zhuǎn)化率以及接枝率、接枝效率。此外,KPS的分解速率也顯著提高,在60℃下,KPS的分解反應(yīng)符合2級反應(yīng),半衰期<1min。關(guān)鍵詞:羥雨基甲基纖維素;(甲基)丙烯酸酯;乳液;接枝共聚合ABSTRACTGraftcopolymerizationofethylacrylate(EA)ontohydro。ypropyImethylcellulose(HPMC)wascarriedoutbytheriseof
3、potassiumpersulfate(KPS)initiatorinaqueousmedium.Amechanism,whichresembledthatofclassicemulsionpolymerization,wasproposed.Theextentofgraftpolymerformationwasmeasuredintermsofgraftingpercentandgraftingefficientasfunctionsofreactiontemperature,monomerconcentration,pre—interacting,timeandisopropano
4、l(IPA).Graftingpercenthadmaximumattemperatureof65℃.a(chǎn)ndgraftingefficiencydecreasedastemperatureincreased.Longerpre—interactingtimebetweenKPSandHPMCandhighermonomerconcentrationresultedinhighergraftingpercentandgraftingefficiency.TheeffectofIPAontheextentofgraftpolymerformationwasa]soexamined.Stab
5、lehigh—solid—contentemulsionwasobtainedinthepresenceofIPA.TheformationofgraftcopolymersweFeconfirmedbyIRandDSC,Theglasstransitiontemperatures(Tg)ofHPMCandPEAapproachedeachotherduetotheimprovedcompatibilitywithHPMC·-g-·PEAasacompatibilizer.Thegraftcopolymerswithlowlevelofgraftingpercentexhibitedb
6、admechanicalpropertiesduetopoorcompatibility.ItwasfoundthattheextentofgraftpolymerformationonHPMCwasappreciablyreducedbythepresenceofDM.ItwasinterpretedasduetOthechaintransfereffectofDM.AninterestingdiscoverywasthedramaticallyaccelerationofdecompositionofKPS,withthereactionrateshowed2一orderwithr
7、especttotheconcentrationofKPSandahalf-time0f1essthan1minat60℃WaSobserved.Keywords:11ydroxypropylmethylcellulose;(meth)acrylate;emulsion;graftcopolymerization獨創(chuàng)性聲明本人聲明所呈交的學位論文是本人在導(dǎo)師指導(dǎo)F進行的研究工作和取得的研究成果,除了文中特別加以標注和致謝之處外,論文中不包含其他