苏州大学聚合物合成与改性作业答案

Chapter11、Whataremolecularweightandpolydispersityofpolymers?Themolecularweightofpolymersisactuallytheaveragemolecularweightofpolymers,whichisusedtodescribethesizeofpolymersandisassociatedwiththepropertiesofpolymers,likemechanicalstrengthandviscosity.Andthereareusuallythreekindsofmolecularweightofpolymersaccordingtodifferentmethods:number-averagemolecularweight,weight-averagemolecularweight,andviscosity-averagemolecularweight.NxMxMnNx2NxMxMwNxMx1/1NxMxMvNxMxPolydispersityofpolymersistheexactmolecularweightdistributionofpolymersandliesinthestatisticalvariationspresentinthepolymerizationprocesses.TheratioofthetwoaveragemolecularweightsMw/Mnisoftenusefulasameasureofthepolydispersityofpolymers.2、Pleaselisttherepeatingunitofthefollowingpolymersandmonomerstosynthesizethem:PSt、PMMA、PAA、PVA、PIP、PTFE.PSt(polystyrene)PMMA(polymethylmethacrylate)PAA(polyacrylicacid)PVA(polyvinylalcohol)(imaginary)PIP(polyisoprene)PTFE(polytetrafluroethylene)3、Pleaselistthesourcestogeneratefreeradicals.Thermaldecomposition、photochemicaldecomposition、oxidation-reductionreaction、highenergyparticleradiation、sonication、plasmainitiation、electrolyticinitiation.4、Pleaselistmainreactionsofradicals.Radicaladditionreaction、radicalcouplingreaction、radicaldisproportionationreaction、radicaldissociationreaction、radicaltransferreaction.5、Pleaselistthreemonomerswhichcanbepolymerizedviaradical,ionicandcoordinationpolymerizations.Radical:styrene、vinylchloride、ethylene、acrylonitrile、methacrylamide;Ionic:isobutylene、isoprene、iospropylvinylether、styrene；Coordination:propene、styrene、ethylene、isoprene;6、Can1,1-diphenylethylenebesubjectedtopolymerization?Why?No,sincethephenylsubstitutesgroupsarebulkywhichcancausestrongstericeffects,1,1-diphenylethylenecanonlyformdimer.7、Pleasedrawchemicalstructuresofpoly(styrene-alt-maleicanhydride).8、Pleaselistelementalreactionsofchainpolymerization.Chaininitiation、chainpropagation、chaintermination、chaintransfer.9、Pleaselistthetypesofmicrostructuresformonosubstitutedvinylmonomers.Head-to-tail(1,3-placement,thesubstitutesareonalternatecarbonatoms):Head-to-head(1,2-placement):10、Pleaselistthetypesofchaintransferreactioninfreeradicalpolymerizationandgivetwoexamplesofchaintransferagents.Chaintransfertomonomer,solvent(chaintransferagent),initiator,andpolymer;Chaintransferagent:carbontetrachloride,1-butanethiol,carbontetrabromide,triethylamine.11、Whatarethecharacteristicsofradicalpolymerization?Itconsistsoffourelementaryreactions——initiation,propagation,termination,andtransfer;Therateofinitiationisthelowestone,whichcontrolstheoverallrateofpolymerization;Slowinitiation,fastpropagation,fasttermination,andeasytermination;Theproductsonlyconsistsofmonomer,polymers(activespecies,ifpossible);Highpolymersexistasthepolymerizationbegins;Conversionisincreasedbytheextensionofpolymerizationtime;Thereisnoreactionbetweenmonomer-monomer,monomer-polymer,andpolymer-polymer;Theconcentrationofmonomerdecreasesandpolymerincreasesasthepolymerizationgoeson.12、Notions:efficiencyofinitiation,kineticchainlength,autoacceleration(geleffect),radicallife,polymerizationrate,inhibition,retardation.Efficiencyofinitiation:theratioofinitiatorswhichareusedtoinitiatepolymerizationtoinitiatorsthatdecomposeinthewholeprocessofpolymerization;Kineticchainlength:theaveragenumberofmonomermoleculesconsumedpereachradicalwhichinitiatesapolymerchain,anditcanbegivenbytheratioofpolymerizationratetoinitiationrate;2pppittMkMRRvRRkAutoacceleration:autoaccelerationisacommonphenomenonwherethepolymerizationrateincreasesforcertainperiodinradicalpolymerizationwhichiscausedbytheincreaseofthesystemviscosity,thusisalsocalledgeleffect;Radicallife:thetimefromproductiontoterminationofradicals;122sptstpMMkMRtkkRPolymerizationrate:describehowthepolymerizationconcentrationorconversionchangeswiththereactiontime,whichconsistsofthreeelementaryreactions—initiation,propagation,andtermination,andcanbeexpressedbythefollowingequation:pdMdPRdtdt1/21/2()dpptfkRkIMkInhibition:aphenomenoninwhichthereactivityofradicalsandstoppedandthepolymerizationiscompletelyhaltedduetotheadditionofinhibitors;Retardation:aphenomenoninwhichonlyaportionoftheradicalsarestoppedandpolymerizationoccursatalowerrateandlowerpolymermolecularweightduetotheadditionofretarders;13、Chemicalstructures:AIBN,BPO,KPS,cumylhydroperoxide.AIBN(2,2-azobisisobutyronitrile)BPO(benzylperoxide)KPS(potassiumpersulfate)cumylhydroperoxide14、Pleaselisttherelationbetweendegreeofpolymerizationandkineticchainlength.Whennochaintransferoccurs:Couplingtermination:2Xnv;Disproportionationtermination:Xnv;Thetwomodescoexist:2vXnv2vXnCDC、DrepresentthepercentageofcouplinganddisproportionationWhenchaintransferoccurs:1(2)2MSISIaCCCXnvMM15、Pleaseexplainbasicprinciplesofdilatometermethod.Theprinciplesofdilatometermethodarebasedonthelinearrelationshipbetweenthevolumecontractionandtheconversionofthereactionsystem:100%mpmVVKVWheremVisthespecificvolumeofmonomer,pVisthespecificvolumeof