苏州大学聚合物合成与改性作业答案.docx

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