英语科技论文写作结课论文

英语科技论文写作结课论文ThePreparationandResearchOfEpoxyResinModifiedWater-bonePolyurethaneEmulsion1.IntroductionTherearevarioustypesofrawmaterialsforsyntheticwater-bonepolyurethaneemulsion,includingnotonlymainrawmaterialssuchasisocyanatesofpolyurethaneresin、polyhydricalcoholsorpolyamine,butalsoauxiliaryrawmaterialslikechainextender、catalyticagent、neutralizer.Bydifferentsyntheticprocessesandcompounddesignswecanproducewater-bonepolyurethaneswithdifferentproperties[1].Thegreatadvantageofwater-bonepolyurethaneisusingwaterasdispersionmedium,themethodweusetocomposewater-bonepolyurethaneisself-emulsificationmethod,asitneednottoaddemulsification.Astheepoxyresinhasmanyexcellentproperties:greatbindingpowerandintensity,andithashydroxideradicalwhichcanreactwith–NCOinpolyurethanethenreachtheaimofmodifyingpolyurethane[2].Thismodificationovercomesthepolyurethane’sshortcomingtoalargeextent[3].Inourexperiment,wediscussedthetemperatureandtimeofpre-polymerization、thetemperatureofemulsification、theRvalue、theadditionofDMPA、themolecularweightofPEG、theadditionofBDOandEDA,thenmakesurethebestmatching.AfterwardsweuseepoxyresintomodifyPU,anddiscussedtheadditionofDMPA、thedifferentkindsofepoxyresinsandtheadditiontoaffectthepropertiesofwater-bonePU,thendeterminethebestmatchingoftheadditionofDMPAandepoxyresinwhichenhancedthepropertiesofPUthegreatestdegree[4].2.ExperimentWefirststudiedthereactiontemperature,reactiontimeonthepropertiesofwater-bonepolyurethaneemulsion.Theninthebestreactiontemperatureandtimewediscusseddifferentratioofrawmaterialsaffectedthewater-bonepolyurethaneemulsion’sappearance、storagestabilityandthewaterproof、themechanicalpropertyandtheheatenduranceofthecoating.Fromthisweobtainedthebestformula.Thepreparationofepoxyresinmodifiedwater-bonepolyurethaneemulsionmainlydividedintotwostages[5]:Thefirststageispre-polymer,andthemainreactionisthe–NCOinMDIreactwith–OHinPEGtoproduceCarbamicacidesterbond,whenaddedDMPAthen–COOHadded,afterwardsaddedBDOtoincreasethelengthofthechain,thelastaddingthe–OHtobringintheepoxygroups;Thesecondstageisneutralizationemulsification.Wecooledthepre-polymerto30°,thenaddTEAtoneutralize–COOH,followedundertheactionofhigh-speedshearingjoinEDAaqueousemulsion,amongthistheepoxyringopeningto–OH.Atlasttheepoxyresinmodifiedwater-bonepolyurethaneemulsionmade.ThepictureinthefollowingistheanalysisofFTIRoftheepoxy、thewater-bonepolyurethaneemulsionandtheepoxymodifiedwater-bonepolyurethaneemulsion.Picture1TheFTIRofepoxy、WPUemulsionandepoxymodifiedWPUemulsion(a:epoxy;b:WPUemulsion;c:epoxymodifiedWPUemulsion)TheanalysisofFTIRindicatedthatafterepoxymodified,-NCOreactedwiththe–OHintheepoxyandformedcarbamicacidester,alsothepictureshowedthattheepoxyintroducedtothemainchainofWPUsuccessfully.Besides,thepictureillustratedthatintheprocessofmodifyingtheringopeningreactionhappened.3.ConclusionTheresultsindicatedthatthepreparedwaterbornepolyurethaneemulsionshowsprettyappearanceandexcellentstability,asthepre-polymerizationreactiontimeandtemperaturearerespectively180minand70℃aswellastheemulsificationtemperaturebeing30℃;WiththeincreaseofRandDMPAcontent,thetensilestrengthofwaterbornepolyurethanefilmalsoincreasedandthebreakingelongationtendtodecrease,however,thewaterresistanceofthefilmdecreasedwiththeincreaseoftheRvalueandincreasedwiththeincreaseoftheDMPAcontent.Thereby,theoptimumRandoptimalcontentofDMPAweredeterminedrespectivelyas1.7and5%~7%;additionally,takingPEGasmaterial,whichhaslargerrelativemolecularmass,thepreparedwaterbornepolyurethaneemulsionappearsbrilliantlyandshowsgreatstabilityasthecontentsofBDOandEDAare6%~8%and2%respectively.Moreover,itwasmeasuredthatthewaterabsorption,tensilestrengthandbreakingelongationofthefilmarerespectively11.46%,10.46MPaand402%.Althoughlittlechangehappenstotheappearanceandstabilityofthewaterbornepolyurethaneemulsion,whichwasmodifiedbyEP,thewaterresistance,mechanicalpropertiesandthermalstabilityofthefilmshowgreatchangealongwiththedifferentadditionsofEP.Accordingtotheresearch,thewaterbornepolyurethaneemulsionshowsbetterperformanceastheEPcontentis8%.Furthermore,theperformanceofthewaterbornepolyurethaneemulsionmodifiedbyE-44isbetterthanthatmodifiedbyE-51.Thewaterabsorption,tensilestrengthandbreakingelongationofthefilm,whicharemodifiedbyE-44,arerespectively8.41%,15.52MPaand318%.TGanalysisindicatedthatthethermalstabilityofthefilm,whichwasmodifiedbyEPsignificantlyimproved.Moreover,thethermalstabilityofthefilm,whichwasmodifiedbyE-44,isbetterthanthat,whichwasmodifiedbyE-51.AccordingtotheFTIRanalysis,theEPhasbeensuccessfullyintroducedtothewaterbornepolyurethaneMolecularchain,andRing-openinghappened.4.ReferencesPanZuren.Polymerchemistry[M].Beijing:Chemistryindustrypress,2007,47-49.NobleKL.Waterbornepolyurethanes[J].ProgressinOrganicCo