苏州大学聚合物合成与改性作业答案.docx
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苏州大学聚合物合成与改性作业答案.docx
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苏州大学聚合物合成与改性作业答案
Chapter1
1、Whataremolecularweightandpolydispersityofpolymers?
Themolecularweightofpolymersisactuallytheaveragemolecularweightofpolymers,whichisusedtodescribethesizeofpolymersandisassociatedwiththepropertiesofpolymers,likemechanicalstrengthandviscosity.Andthereareusuallythreekindsofmolecularweightofpolymersaccordingtodifferentmethods:
number-averagemolecularweight,weight-averagemolecularweight,andviscosity-averagemolecularweight.
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;
●Autoacceleration:
autoaccelerationisacommonphenomenonwherethepolymerizationrateincreasesforcertainperiodinradicalpolymerizationwhichiscausedbytheincreaseofthesystemviscosity,thusisalsocalledgeleffect;
●Radicallife:
thetimefromproductiontoterminationofradicals;
●Polymerizationrate:
describehowthepolymerizationconcentrationorconversionchangeswiththereactiontime,whichconsistsofthreeelementaryreactions—initiation,propagation,andtermination,andcanbeexpressedbythefollowingequation:
●Inhibition:
aphenomenoninwhichthereactivityofradicalsandstoppedandthepolymerizationiscompletelyhaltedduetotheadditionofinhibitors;
●Retardation:
aphenomenoninwhichonlyaportionoftheradicalsarestoppedandpolymerizationoccursatalowerrateandlowerpolymermolecularweightduetotheadditionofretarders;
13、Chemicalstructures:
AIBN,BPO,KPS,cumylhydroperoxide.
AIBN(2,2-azobisisobutyronitrile)BPO(benzylperoxide)
KPS(potassiumpersulfate)cumylhydroperoxide
14、Pleaselisttherelationbetweendegreeofpolymerizationandkineticchainlength.
Whennochaintransferoccurs:
●Couplingtermination:
;
●Disproportionationtermination:
;
●Thetwomodescoexist:
C、Drepresentthepercentageofcouplinganddisproportionation
Whenchaintransferoccurs:
●
15、Pleaseexplainbasicprinciplesofdilatometermethod.
Theprinciplesofdilatometermethodarebasedonthelinearrelationshipbetweenthevolumecontractionandtheconversionofthereactionsystem:
Where
isthespecificvolumeofmonomer,
isthespecificvolumeofpolymer,andKrepresentstherateofchangeofvolumewhentheconversionis100%.
Theconversion(C%)hasalinearrelationshipwiththevolumecontraction:
Where
istheoriginalvolumeofthesystem,and
denotesthecontractionvalueofvolume.
Thedilatometerconsistsoftwoparts:
thelowerpartisthereactor,andtheupperoneiscalibratedcapillary.Bymeasuringthevolumecontractionvalueatdifferenttime,wecangettheconversionchangewithtime,andgetthepolymerizationrate.
Chapter2
1、Whatarebasicfeaturesoflivingpolymerizationsystems?
●Constantnumberofpolymerchains;
●Nopermanentchainstoppingreactions;
●Controlofchaingrowth;
●Dormantandactivestates;
●Narrowmolecularweightdistribution;
●TheplotofMnversusmonomerconversionislinear;
●Synthesisofblockcopolymers,starpolymersandcombpolymer;
●Synthesisoftelechelicpolymers(controlofendgroups).
2、Pleaselistthemaintypesof“living”/controlledradicalpolymerization.
●Reversiblehemolyticcleavage:
NMP(nitroxide-mediatedpolymerization,aspecialkindofSFRP,stablefree-radicalpolymerization)andATRP(atomtransferradicalpolymerization);
●Chaintransferprocess:
additionfragmentation,RAFT(reversibleaddition-fragmentationchaintransferpolymerization),CCTP(catalyticchaintransferpolymerization);
●Inifertersmethods;
●Organotelluriumandboroxyl-basedinitiators.
3、PleaselistthebasicmechanismandapplicationofATRP.
ATRPisakindoftransitionmetalmediatedlivingradicalpolymerization,anditsmechanismisshownbelow:
Or
ApplicationsofATRP:
●Topreparewell-definedmacromoleculeswithpredeterminedMwandlowpolydispersity(1.04 ●Tocontrolmacromoleculararchitecture(linear,star,polymerbrush,dendritic); ●Tocontrolmicrostructureofmacromolecules(homopolymer,alternating,block,graft); ●TopreparemacromonomersandfunctionalizedpolymerswithCOOH,OH,NR1R2andvinylgroups(telechelic,multifunctional,end-functionalized). 4、PleaselistthebasicmechanismandapplicationofRAFTpolymerization,anddescribetheprimaryrolesofZandRgroupsofRAFTagent. Mechanism: Application: ●Synthesisofblockcopolymer,gradientcopolymer,andgraftcopolymer; ●Synthesisofpolymerswithdifferentarchitectures,liketelecheliccopolymer,starcopolymer,hyperbranchedcopolymer,andpolymerswithnetwork; ●Introducingfunctionalitiesintopolymers. PrimaryrolesofZandR: Zservesasstabilizinggroups,likephenyl,alkylgroups;Rservesasreinitiatinggroups,andshouldbecleavable,likeisopropylphenylgroup. Chapter5 1、TakeNa-naphthalenebasedanionicpolymerizationofstyreneforexample,pleasedescribethebasicmechanismandapplicationoflivinganionicpolymerization. Mechanism: Application: ●Tosynthesizeamonodispersepolymer; ●Tomeasuretheanionicpolymerizationrate; ●Toprepareablockcopolymer; ●Toprepareatelechelicpolymer. 2、Pleasedescribemainsubclassesofdendriticpolymers. Dendrimers、dendrons、hyperbranchedpolymers、dendrigraftpolymers、dendronizedpolymers. 3、Whatisdendrimer? Howaboutitsmainapplications? Dendrimerisrepetitivelybranchedmolecule,whichistypicallysymmetricaroundthecore,andoftenadoptsasphericalthree-dimensionalmorphology. Dendrimerhaslotofapplications: suprachemistry,catalyst,drugdelivery,genedelivery,optics,sensors,bloodsubstitution,nanoparticles,andotherfields. 4、Pleaselistthreetypesofdendrimers.WhatistherepeatingunitofTomalia-typepoly(amidoamine)dendrimer? Tomalia-typepoly(amidoamine)(PAMAM)、Newkome’sarboroldendrimers、Phosphoruscontainingdendrimers、Fréchet-typepoly(benzylether). RepeatingunitofPAMAMdendrimers: 5、Pleaselistthemainmethodstosynthesizedendrimers. ●Divergentsynthesis: multiplicativegrowthfromacentralcore; ●Convergentsynthesis: preparationstartingfromwhatwillbecometheperipheryofthemoleculeandprogressinginward; ●Clickchemistry: preparationbasedonDiels-Alderreactions,thiol-enereactions,andazide-alkynereactions. 6、Byassumingthecorefunctionalityism,andeachbranchingpointhasthreelinkingpositions
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