资源描述：
《活性自由基聚合,tempo》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。
1、GeorgesMK,etal.(XeroxResearchCenterofCanada)Macromolecules,1993,36,2987-29881.NMP的发现及历史：2,2,4,4-四甲基派啶氮氧稳定自由基 (2,2,4,4-tetramethyl-1-piperidinyloxy,TEMPO)1.NMP的发现及历史：自由基捕获剂、阻聚剂、抗老化剂、热降解抑制剂和热稳定剂等。相对TD，其活性更低，不能引发聚合，且与苯乙烯增长链末端结合的键更弱。分子量与转化率间线性关系！TEMPO/BPO比例对聚合的影响！1.NMP的发现及历史：1.NMP的发现及历史：Manysubse
2、quentstudieshaveconfirmedGeorgesfindingsandhavealsoshownthatincreasingthemolarratioofnitroxidetoinitiatorresultinslowerreactions,lowerPDIs,andlowermolecularweightpolymers.Asacomparison,Georgesperformedasuspensioncopolymerizationofstyreneandbutadienewith(a)andwithout(b)TEMPO.ThePDIofthepolymer
3、withTEMPOwas1.36whilethePDIofthepolymerwithoutTEMPOwas4.61.J.Am.Chem.SOC.1994,116,11185-11186SOLOMON八十年代的工作：用稳定自由基封端研究St、MMA关于引发和终止的结构SOLOMON八十年代的工作：SOLOMON八十年代的工作：1.NMP的发现及历史：Rizzardo等与TEMPO/SFRP失之交臂？温度低，分布宽thetermliving,controlledandstepgrowthwereused.双分子体系BPO:TEMPO=1:1.3Poorlydefinednature
4、oftheinitiatingspecies单分子体系(Unimolecular)：单分子体系可控效果优于双分子体系！Typicallythesepropagatingcarboncenteredradicalsaretransientspecies,tendtodisappearbyself-termination,whichistypicallyadiffusioncontrolledprocess.Thisraisesthequestion,whydoweonlyseeminoramountsofirreversibleterminationinNMP?2.NMP的聚合机理
5、2.NMP的聚合机理2.1平衡的建立：persistentradicaleffectR·活泼自由基，Y·persistentradical,产物只有一种R·,Y·活泼自由基，则产物有三种,1:2:1。2.NMP的聚合机理2.1平衡的建立：persistentradicaleffect2.NMP的聚合机理2.1平衡的建立：persistentradicaleffect2.1平衡的建立：persistentradicaleffectThestableradical(6)iscapableofreactionwitheither(2)or(4)butnotitself.Duetothe
6、factthatirreversibleterminationwilloccurbetweenactiveradicalstheconcentrationofthestableradicalpresentwillincrease.Duetothebuildupinconcentrationof(6),verylittlecouplingproductsbetweenactiveradicals(2)-(2),(2)-(4),or(4)-(4)areformed,astheactiveradicalsreactalmostexclusivelywiththestableorpers
7、istentradical(6).2.1平衡的建立：persistentradicaleffectThePersistentRadicalEffect:APrincipleforSelectiveRadicalReactionsandLivingRadicalPolymerizationsChem.Rev.2001,101,3581-3610HannsFischer2.NMP的聚合机理Radicals(2)and(4)arepresentatverylowconcentratio
