学术英语写作课程论文.docx

学术英语写作课程论文.docx

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学术英语写作课程论文

研究生学术英语写作课程论文

题目

专业班级

学号

学生姓名

任课教师

Abstract

Usingbutylmethacrylates（BMA）asmonomer,Span80asemulsifier,divinylbenzene（DVB）ascross-linkagent,ammoniumpersulfate（APS）/sodiumhydrogensulfite（SHS）asredoxinitiator,thehighoil-absorptionresinwassynthesizedbyconcentratedinverseemulsionpolymerization.Andtheeffectsofdifferentpolymerizationtechnologicalparameters,suchasinitiator,crosslinker,emulsifier,ontheoilabsorbencyofhighoil-absorptionresinswerediscussedindetail.Theresultindicatedthattheabsorptionoftheresinwasabout（g/g）forand（g/g）forchloroform.

Keywords:

concentratedinverseemulsionpolymerization；oilabsorptionresin；oilabsorptionrate

摘要

以甲基丙烯酸正丁酯为单体，二乙烯基苯为交联剂，Span80为乳化剂，过硫酸铵/亚硫酸氢钠为氧化还原引发剂，采用超浓反相乳液法合成了高吸油性树脂。

研究了引发剂用量，交联剂用量，乳化剂用量对树脂吸油性能的影响。

所制备的树脂可以吸收自身重倍的甲苯、倍的三氯甲烷。

关键字：

超浓反相乳液聚合；吸油性树脂；吸油速率

Contents

1

3

3

3

3

3

4

4

4

5

5

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6

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11

1Introduction

Oilpollutionofmarineenvironmentsisbecomingaseriousissue.Withthegrowthoftheoff-shorepetroleumindustryandthenecessityofmarineoiltransportation.Variousmethodsforthetreatmentofspilledoilhavebeentried[1–5].Oneofthemethodstosolvethisproblemisbyusingoilabsorptiveresins,whichcancollectandremovetheoilspilledonwater,andsomehaveprovedtobehighlyefficient[6-7].

Highoil-absorptionresin,beingdifferentfromtraditionaloil-absorbingmaterials,isanewkindofself-swellingoil-absorbingmaterialwithmanyvirtuesofabsorbinglargequantityandvarietyofoils,onlyabsorbingoilfromoil/watermixtureandhighcapacityforoilretention,andhasapromisingfuture.Synthesisandapplicationsofhighoil-absorptionresinshaveveryimportantpracticalsignificanceforenvironmentprotection.

Acrylichasbeenwidelyusedasmonomerstopreparehighoil-absorbingresins.Copolymerizationofacryliccanbeapproachedbyvariousmethodssuchasemulsionpolymerizationandsuspensionpolymerization.However,theresinsobtainedbytheabovemethodsuniversallyhavesomedefectsofcompactstructure[8–10].Itisimportanttoselecta

suitabletechniqueandoptimizetheconditionsofpolymerizationforsynthesisofworkableacryliccopolymer.

Concentratedemulsionsaregel-likeemulsionsinwhichthevolumefractionofthedispersedphaseisgreaterthan.Thedispersedphaseisintheformofsphericalorpolyhedralcellsseparatedbyacontinuous-phasenetworkofthinfilms.Concentratedemulsionshavethreeimportantcharacteristics:

[11-12]

（1）thereducedmonomermobilitybetweencells,becauseofthepresenceofareinforcedsurfactantlayer,cangenerateanearliergeleffect,whichleadstoadelayinthebimolecularterminationreactionand,therefore,ahighermolecularweight;

（2）theparticlesizecanbecontrolledeasilybytheselectionofasuitablesurfactanttypeandconcentration;and（3）apolymercontaininglittlewater,fromwhichpowderyresinsareeasilyformed,canbeobtainedthroughconcentratedemulsionpolymerization.

Incomparisonwiththefourmethodsoffree-radicalpolymerization（bulk,solvent,suspension,andemulsion）,concentratedemulsionshavenotonlyapastelikeappearanceandahighsolidcontentbutalsoanucleationmechanismforthelatexparticle;themorphologyoflatexproductsisdifferentfromthatofconventionalemulsionpolymerization.Forthesereasons,concentratedemulsionpolymerizationdeservestobestudieddeeplyandwidely.Inthis,theinfluencesofemulsifiers，theamountofcross-linkagent,theamountofinitiatorontheabsorptionpropertiesoftheresinwereinvestigated．

2Experiment

Materials

Butylmethacrylate（BMA）analyticalreagentgrade,TianjinKediReagent,wasusedasmonomer;Ammoniumpersulfate（APS）andsodiumhydrogensulfite（SHS）analyticalreagentgrade,TianjinFuchenReagents,wereusedasredoxinitiator;Span80analyticalreagentgrade,TianjinkemioReagent,wasusedasemulsifier;Divinylbenzene（DVB）chemicallypure,ShanghaReagent,wasusedascross-linkagent.

Polymerization

BMAwascarriedoutin150-mlroundbottomflask.Atypicalprocedurewasasfollows:

therequiredamountsofSpan80andDVBwereputintothereactionsystem.ThesystemwaschargedwithN2for20minsandwassealedunderN2.Then32-mldeionizedwaterwasinjectedintothereactionsystem.Afterthat,ammoniumpersulfate（APS）/sodiumhydrogensulfite（SHS）wereinjectedintothereactionsystem.Theflaskwaswhollyimmersedinawaterbathheldat40℃byathermostattostartthepolymerization.Thereactionwascarriedoutunderstirring.Thereactiontimewas3h.Thepolymerwasdriedinvacuumfor24hata35℃.AlloftheingredientsusedaresummarizedinTable1.

Table1.StandardrecipefortheconcentratedinverseemulsionpolymerizationofBMA

Ingredient

Dosage

BMA

7ml

DVB

Span80

H2O

32ml

（NH4）2S4O8

NaHSO3

Measurements

Oilabsorptiontest（goil/gsample）

Theoilabsorbency（W）wasdeterminedbytheweighingmethod.Aquantityof~gofdriedsampleweightedbeforehandwasputintoafilterbagandimmersedintolueneatroomtemperature.Aftergiventimeperiods（24hisneededforfulloilabsorbency）,thefilterbagwiththesamplewasliftedfromtheoilanddrainedfor1min.Thenthesamplewasimmediatelytakenoutandweighed.Theoilabsorbencywascalculatedbythefollowingformula:

W1=（G2-G1）／G1

whereG1istheweightofresinsbeforeoilabsorptionandG2istheweightofresinsafteroilabsorption.

Forthestudyofoilabsorptionrateoftheresins,theabovemeasurementsarerepeatedfromtimetotime.

Regenerationtest

Oil-absorbedsamplesweredriedinvacuumfor24h.Usingtheabovemeasurementstestsoilabsorbencyatfivetimes.

Oilretention

Theresinsafteroilabsorptionwereputindryingovenfor5hat50℃,andthenweighted.

Characterization

TheparticlemorphologyoftheBMApolymerwasobservedwithscanningelectronmicroscopy（SEM;JSM-5610LV）.Thesamplesweresputter-coatedwithAufilmbeforetheexaminationandthevoltageis20kV.

3ResultsandDiscussion

Theeffectofcross-linkingamountontheoilabsorbency

Theoil-absorbingprocessofhighoil-absorptionresins,aslowdegreeofpolymer,wasswellingprocess.Asevidence,notonlythesortsofcrosslinkercanaffecttheinterstitialspacestructuresoftheresins,butalsotheamountofcrosslinkercandirectlyinfluencetheparticlemorphologyandthedegreeofcrosslinkingoftheresins.Figure1illustratedtherelationshipbetweenoilabsorbencyandtheamountofDVB.AsshowninFig.1,therewasamaximumpoint.WhentheamountofDVBwassmallerthanthatatthemaximumpoint,theoilabsorbencyincreasedwithincreasingDVB.However,theoilabsorbencydecreasedwithincreasingDVBwhenthemountofDVBwaslargerthanthatatthemaximumpoint.

Theeffectofcross-linkingamountontheoilabsorbency

Itiswellknownthatanincreaseintheamountofacrosslinkercausesthedensernetworkofthepolymer.AddinglessamountofDVB,thedegreeofcrosslinkingoftheresinswaslower,thetridimensionalnetworkwasnotsatisfying.Theresinsweresolubleinoilandtheviscosityoftheproductincreased.Theresinswhichhaveabsorbedoilcannotrecover.Iftheamountofcrosslinkerwastoogreat,thecrosslinkerdegreeincreasedandthenetworkspaceintheresinsdecreased.Asaresult,theoilabsorbencyreduced.Theresinshadthebestoilabsorptivitywhentheinterstitialspaceisatitsoptimumvalue.Figure.1showsthatthisoccursat.

Effectoftheamountoftheemulsifierontheoilabsorbency

Inconcentratedinverseemulsionpolymerization,althoughemulsifiersdonotdirectlytakepartinthereaction,theyhavereducinginterfacetension,emulsification,anddispersingeffects.Themaindifferencewithaconventionalemulsionpolymerizationisthatapartofemulsifierispresentatthemonomer/waterinterfaceandnotonlyatthepolymerparticle/waterinterface.Anotherpointisthat,inmostcases,theamountoftheemulsifierisverylow,sothattheparticlesformedbytheemulsionprocessarenotstableenoughandeasilycoalescetogivemuchlargerprimaryparticles.

TheeffectofSpan80concentrationontheoilabsorbency

Theeffectofinitiatoramountontheoilabsorbency

BMApolymerasshort-chainhighoil-absorptionresinswerepreparedbyconcentratedinverseemulsionpolymerization,withtheformationofradicalsinwaterphase,andtheradicalswerecapturedbytheexistingparticlesinsidethewaterphase.TheeffectsofvariousAPSandSHSconcentrationsbasedontheweightofBMAontheoilabsorbencywereshowninFig.3

Withincreasinginitiatorconcentration,theoilabsorbencyincreased,andthendecreased.TheconcentrationofAPSandSHSneededtobeinacertainrangetoensurethatthereactionproceedssmoothly.

Theeffectofinitiatoramountontheoilabsorbency

Inthereactionsystem,theconcentrationoftheinitiatorwillcauseeffectsonthereactionrate,themolecularweightoftheresins,andthecrosslinkingdegree.Moreover,itisknownthatthemoreinitiatorwillgeneratemoreactivecentersinordertoincreasetheconversionandthegelfractionanddecreasethelengthofthebasicchaininpolymersystems.Asaresult,thechainlengthbetweencrosslinkingpointsofthenetworkdecreasedandthecrosslinkdensityincreasedwiththeincreaseoftheinitiatorconcentration.Therefore,thefinalresultwasadecreaseoftheoilabsorbency.

Oilabsorptionrateoftheresins

TheSEMmicrophotographsofparticlespreparedbyconcentratedinverseemulsionpolymerizationwasdisplayedinFig.4.Itwasapparentthatthereweremanysmallrandomporesinthecrosslinkedresinspreparedbyconce