Study On Copolymerization Of Alkyne/Alkene Functionalized 1,1'-Diphenylethylene(DPE) Via Living Anionic Polymerization

The development of new methods for regulating the sequence structure,revealing the structure-activity relationship(SAR)between sequence and properties have important significance.Functional groups can be introduced into polymer chain qualitatively,quantitatively and locationally by adjusting the substituents of 1,1'-diphenylethylene(DPE)derivatives.Revealing the mechanism of living anionic polymerization(LAP)kinetics affecting the sequences,and establishing the model of sequence regulation is the significant direction.Furthermore,the understanding of the SAR in synthetic polymers is far from that of biopolymers.In consequence,exploring the SAR between sequence and properties is still critical.Then,how to build a bridge between sequence-controlled polymers and post-functionalized polymers has become a problem,that is,it is necessary to establish precise,efficient,and convenient synthesis methods for sequence-controlled functionalized and topological polymers.With the "bricks" concept,the synthesis of complex structure can be facilitated,providing new thinking for building the bridge of post-functionalization.This study investigated the LAP kinetics around a series of DPE derivatives,and established the theoretical model of sequence control based on DPE derivatives.With the"click" reaction,the synthesis of fluorescence-labeled polymers with controlled-sequence were realized.A precise,efficient,and convenient conversion method of functional groups in post-functionalization was developed,and the effects of sequences on the luminescence were explored.The synthetic route of SIS with di-lithium method was established,and ?,?-end alkyne-functionalized SIS was efficiently synthesized.Combined with the study of thiol-yne"click" reaction between polymers,the preparation of thermoplastic elastomer materials with functional groups and topology could be realized.The main results were as follows.(1)Alkynyl functionalized DPE derivatives,including trimethyl((4-(1-phenylvinyl)-phenyl)ethynyl)silane(DPE-yne),1-phenyl-1'-[4-[2-(triisopropylsilyl)ethynyl]phenyl]ethylene(DPE-TPSE)and 1-(4-methyloxyphenyl)-1'-[4-[2-(triisopropylsilyl)ethynyl]phenyl]ethylene(DPE-OTPSE)were synthesized.The coupling reaction of alkynyl functionalized DPE derivatives in living anionic polymerization was effectively suppressed by adjusting the bulk of protecting group and implementing the ternary polymerization.The alkynyl functionalized DPE has high reactivity and tends to produce a serious cross-propagation in living anionic copolymerizations with styrene verified by KMC simulation.Through in situ 1H NMR method,the binary copolymerizations of alkynyl functionalized DPE and styrene were monitored when the feed ratio of styrene to DPE derivatives was 4:1.The study found that the sequence structure of DPE-yne showed alternating feature,and rst was 0.05,while the sequence structure of DPE-OTPSE showed gradient feature,and rst was 0.27.The ternary copolymerization of DPE-yne,DPE-NMe2 and St was monitored in real time.The sequence structure of DPE-yne/DPE-NMe2/St terpolymer is:the initial is alternating sequence of DPE-yne and styrene,the intermediate is ternary sequence,and the late is gradient sequence of DPE-NMe2 and St.(2)The copolymerization of alkyl-substituted DPE(DPE-alkyls)and styrene was monitored by in situ 1H NMR method.The results showed that,the copolymers of different DPE derivatives and St would have identical sequence when DPE derivatives exhibit exactly the same reactivity under the same conditions.Statistics of the polymerization degree of styrene between adjacent DPEs(Si-j)were made to quantify the precision of statistical sequence structure.The results show the standard deviation of Si-j gradually increases,and the sequence precision gradually deteriorates with increasing the amount of styrene.The degree of sequence controllability could be distinguished by the magnitude of the Si-j slope.Then,coumarin-labeled,tetraphenylethylene-labeled,and pyrene-labeled sequence-controlled polymers were synthesized and the effect of sequence on luminescence was explored.The sequence structure has a significant effect on the ratio of the fluorescence intensity of the excimer over that of the independent moiety(IE/Im)of pyrene-labeled polymers,Combined with molecular dynamics simulation and fluorescence blob model,it can be shown that the Si-j between adjacent DPE units could affect the IE/IM pyrene-labeled polymers.(3)The polymer bricks,including the in-chain alkyne-functionalized,the chain-end alkyne-functionalized and thiol-functionalized,were synthesized.The features of thiol-yne click reaction between polymers were studied.The mono-adducts could be efficiently obtained with high efficiency of 90%.However,di-adducts could not be achieved due to the large steric hindrance when the in-chain thiol-yne addition was carried out.The in-chain di-adduct could be performed efficiently by increasing the spacing between functional moieties.A bifunctional di-lithium initiator was synthesized by the reaction of 1,3-bis[1-(p-methylphenyl)vinyl]benzene(MPEB)with a monofunctional initiator.Using di-lithium compound as initiators,lithium t-butoxide as the modifier of isoprene polymerization,and potassium t-butoxide as the modifier of styrene polymerization,the SIS triblock elastomer with low vinyl content was synthesized.The SIS triblock synthesized by di-lithium method was end capped with the alkynyl functionalized DPE derivatives,DPE-yne,and the ?,?-end alkynyl functionalized SIS elastomer brick was synthesized with an efficiency higher than 90%.Combined with the study of thiol-yne click reaction between polymers,the preparation of thermoplastic elastomer materials with functional groups and topology could be realized.