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简介:构造工程的地里的聚合物修正有历史将近90年。尽管那些修正被分类进物理修正,到某程度的机械性质,水抵抗,化学抵抗和耐久性被不同聚合物修正改进了。获得似水泥的材料的更好的性能,化学修正被测试了。在这研究,环氧基树脂与它的相应hardener在修改系统作为一个占优势的修饰词被设计了。氨基的sulfonate,添加剂,被用来改进系统可使用性。当它有特殊的功能的组,功能的silane被用来在环氧基树脂,水泥一半和氨基的sulfonate之中建立连接。红外,拉曼光谱学,DSC和NMR执行的调查表明化学连接在修改系统在所有部件之中被建立了。当曲折力量和紧张实质地被改进了,曲折测试结果介绍化学修正的好效果。
简介:Thepurposeofthisstudywastouseathree-componentphotoinitiationsystemcomprising1wt%CQ(camphorquinone),2wt%DMAEMA(2-(dimethylamino)ethylmethacrylate)and2wt%Ph2I+PF6-(diphenyliodoniumhexafluorophosphate)toinitiatethecopolymerizationofthematrixresinswhichcombinebisphenol-S-bis(3-methacrylate-2-hydroxypropyl)ether(BisS-GMA)withtheexpandingmonomerunsaturatedspiroorthoesters2-methylene-1,4,6-trispiro[4,4]nonane(MTOSN),forminimizingthevolumetricshrinkagethatgenerallyoccursduringpolymerization.ItwashypothesizedthatMTOSNwouldexpandvolumetricallyduringpolymerizationunderthethree-componentphotoinitiatorsystemandfurtherreductionsinvolumetricshrinkagewouldbeobtained.Theperformancestudywhichconsistsofdegreeofconversionandconditionofthering-openingreactionsofMTOSN,volumetricshrinkageandmechanicalpropertiesincludingtensilebondstrength,compressivestrengthandVicker'shardnesswerecarriedoutrespectivelybyFouriertransferinfrared,thedilatometerandtheuniversaltestingmachine.Theresultssupportedthatthedentalcompositesbasedontheexpandingmonomerandthree-componentphotoinitiatorsystemengenderedagreaterdecreaseofvolumetricshrinkageandbettermechanicalproperties.
简介:Theflowfieldinacoldmodelof2500t/dfive-stagecyclonepreheaterandprecalcinersystemwasnumericallysimulated.Renaultstressmodel(RSM)turbulentmodelwasadoptedtosimulatetheflowfield,andahybridmeshschemewasselectedtogeneratecalculationmesh.Withthefirstorderupwinddifference,finite-volumemethodwasusedtoconvertturbulentequationsintodifferenceequationspressure-velocitycouplingwhichweresolvedbytheclassicsimplealgorithm,andduringthecourseofnumericalsolution,meshself-adaptingtechnologywasapplied.Themainflowfieldstructuresofthewholesystemandeachpartofthecoldmodelwerestudiedbyanalyzingthesimulationresults.
简介:ThethermodynamicphasestabilityareadiagramsofBCl3-NH3-SiCl4-H2-ArsystemwereplottedviaFactsagesoftwaretopredictthekineticexperimentalresults.Theeffectsofparameters(ie,partialpressureofreactants,depositiontemperatureandtotalpressure)onthedistributionregionsofsolidphaseproductswereanalyzedbasedonthediagrams.Theresultsshowthat:(a)Solidphaseproductsaremainlyaffectedbydepositiontemperature.TheareaofBN+Si3N4phaseincreaseswiththetemperaturerisingfrom650to900℃,anddecreaseswiththetemperaturerisingfrom900to1200℃;(b)Whentemperatureandtotalpressureareconstants,BN+Si3N4phaseexistsatahighpartialpressureofNH3;(c)Theeffectoftotalsystempressureiscorrelatedtodepositiontemperature.Thetemperaturerangingfrom700to900℃underlowtotalpressureistheoptimumconditionforthedeposition.(d)Appropriatekineticparameterscanbedeterminedbasedontheresultsofthermodynamiccalculation.Si–B–Ncoatingisobtainedvialowpressurechemicalvapordeposition.TheanalysisbyX-rayphotoelectronspectroscopyindicatesthatB–NandSi–Narethemainchemicalbondsofthecoating.
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简介:Mechanicalpropertiesofepoxyresinwereinvestigatedbyaddingcore-shellelasticparticles(CSEP).Theresultsindicatedthatoptimizedcore-shellratiowas60/40andtheloadingvolumeofCSEPwas10phr(perhundredpartsofepoxyresinbyweight).Theimpactstrengthofmodifiedsystemsincreasedapparentlywiththedecreaseofcoresizes.However,theshearingstrengthchangedgentlywiththeparticlesizes.CSEPwithlightlycrosslinkedrubberycoreshowedmoreeffectivenessontoughnessthanothers.Withsolutionblending,CSEPcouldbedispersedinepoxymatrixwell,andthemorphologiesofdispersedrubberdomainswerecontrolledperfectlybyCSEPwhosestructurewaspredesigned.Acavitation-shearingbandtoughnessmechanismwasobservedfromtheSEMmicrographsoffracturesurface.Italsowasfoundthatthedeformingtemperature(DT)ofmodifiedepoxydidnotdeclineapparently.