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1、摘要聚甲基硅次乙炔基硅烷固化機理的研究聚甲基硅次乙炔基硅烷(簡稱MSE)含有Si.H和C三C鍵,經(jīng)150.180℃的預(yù)處理后可得到耐熱樹脂,再經(jīng)高溫?zé)峤夂罂傻玫礁吡呀鈿埩袈实腂.SiC陶瓷。固化過程對樹脂的熱穩(wěn)定性和陶瓷產(chǎn)率會有很大的影響,因此,有必要對MSE的固化過程和固化機理進行研究。本文采用DSC和FTIR對MSE等溫(160、170、180℃)預(yù)處理過程進行了研究。結(jié)果表明:MSE等溫處理過程中發(fā)生氫硅化反應(yīng),反應(yīng)程度約為33%;預(yù)處理時間t與處理溫度T之間滿足關(guān)系t(T)/t(T+1OK)=2:1。采用動態(tài)和等
2、溫DSC實驗法對MSE低聚物的固化動力學(xué)進行了研究,分別給出了MSE固化反應(yīng)的動力學(xué)參數(shù)(表觀活化能Ea、頻率因子A和反應(yīng)模型墳O【)):(1)根據(jù)動態(tài)實驗得出Ea-110.OkJ/mol,A=2.77×109s~,反應(yīng)級數(shù)模型f【Q)=(1.0【)n(反應(yīng)級數(shù)n-O.93,準(zhǔn)一級反應(yīng));(2)根據(jù)等溫實驗得出Ea-112.4kJ/mol,A-5.46×109s一,JMA模型fj(a)=n(1.伐)[.1n(1.0【)]1.1m(n=2.53,無規(guī)成核、三維擴散控制)。采用FTIR、NMR、Ⅺm和GC.MS等方法對MSE
3、固化機理進行了研究。指出MSE的固化過程由以下反應(yīng)完成:SiH和C三C的氫硅化反應(yīng)、C三C間的加成和成環(huán)反應(yīng)、重排反應(yīng)和氧化交聯(lián)反應(yīng)(有氧條件)。北京化T人學(xué)碩.1j學(xué)位論文關(guān)鍵詞:固化動力學(xué)固化機理氫硅化反應(yīng)預(yù)處理聚甲基硅次乙炔基硅烷IIAbstralctThermosettingMechanismStudy0fPoly【(methylsilylene)ethynyleneJAbstractPoly[(methylsilylene)ethynylene](MSE)whichcontainsSi—HandC三Cbonds
4、,producesaVe巧highmemalstableresinbypretreatmentat150.180℃,andbypyr01ysisgiVesp—SiC—containingceramicsinhighyield.Thecuringprocessafrectsthethennalstabilityofcuredresinandceramicyieldindecompositionoftheresin.Therefore,itisnecessarytostudythecuringprocessandcuring
5、mechanismofMSE.TheisothemalpretreatmentprocessofMSE(at160,170and180℃)wasinVestigatedbyDSCandFTIR.TheresultsshowedthathydrosilylationofMSEproceededonisothemlalprocesswiththereactivedegreeof印proximately33%,thepretreatmeattimetandthetemperatureThasarelationshipoft(T
6、)/t(T+1OK)=2:1.ThecuringkineticsofMSEwasinVestigatedbymeansofdy[1alnicandisothennalDSCeXperiments.The妯neticparameters(the印paremactivationene唱yEa,the疳equencyfactorAandthereactionmodelf(O【))wereobtained仔omDSCexpe訂mentsrespectiVely.Resultsareasfollows:(1)Ea=110.OkJ/
7、mol,A-2.77×109andreaction.ordermodel墳0【)=(1.0【)n(thereaction北京化工大學(xué)碩l:學(xué)位論文ordern=O.93,pseudofirst-orderreaction)and(2)E。=l12.4kJ/mol,A=5.46×109s。1andnucleationmodel墳0【)=n(1一Cc)[.1n(1一O【)]1·1/n(theparametern=2.53,homogeneousnucleationandthree-dimensionalgrowth).The
8、themosettingmechanismofMSEwasstudiedusingFTIR,NMR,XItD,GC.MSandsoon.TheresultsshowedthatthecuringprocessofMSEconsistreactionsofhydrosilylationbetweenSi·HandC三C