新型“蜈蚣形”苯乙烯-甲基丙烯酸甲酯共聚物的合成

结合活性阴离子聚合和原子转移自由基聚合(ATRP)合成了结构清楚的A2B型“蜈蚣形”苯乙烯-甲基丙烯酸甲酯共聚物(PS-PS-PMMA). 合成路线包括含1, 1-二苯基乙烯(DPE)侧基的聚苯乙烯(PS)主链与活性聚苯乙烯基锂的偶联反应和产生的1, 1-二苯基甲基阴离子引发聚合甲基丙烯酸甲酯的反应, 其中, 主链PS通过ATRP和Wittig反应制得. 通过1H NMR, IR, SEC, SLS和 DSC等方法对所得“蜈蚣形”共聚物进行了表征.     

基于负离子-RAFT机理转换合成两亲性高度支化嵌段共聚物

报道了一种从引发型单体CX(inimer)出发、通过负离子-RAFT机理转换,制备两亲性高度支化聚合物的方法.首先,用仲丁基锂(s-Bu Li)与双官能团的1,1-二苯基乙烯衍生物MDDPE反应制备inimer,并通过inimer与苯乙烯共聚制备高度支化聚苯乙烯活性负离子;然后将末端负离子通过与CS2和1-溴乙基苯反应,原位转化为双硫酯基团,并作为大分子链转移剂(dendritic-CTA)调控N-异丙基丙烯酰胺(NIPAM)聚合,从而得到含聚苯乙烯(PS)和PNIPAM的两亲性支化嵌段共聚物.用联有光散射的凝聚色谱(GPC-MALLS)以及1H-NMR对产物进行了表征,并通过荧光探针、动态光散射(DLS)、透射电镜(TEM)等技术对两亲性支化嵌段共聚物在的溶液性质和乳化性能进行了研究.结果表明,该聚合物在水溶液中表现出独特的随温度变化的聚集行为,在水/油两相体系中具有极强的乳化能力.     

高密度柱状聚合物刷的合成

通过铜催化的叠氮-炔偶联反应(CuAAC),利用grafting-onto方法合成每个主链重复单元带有多于一条侧链的高接枝密度的柱状聚合物刷.首先,合成了带有缩酮保护的甲基丙烯酸2,2-双羟甲基丙酯单体(bisMPMA),并通过可逆加成-断裂链转移(RAFT)聚合得到窄分子量分布的线形聚合物.在酸性条件下脱去缩酮保护后,以羟基与戊炔酸酐的酯化反应,得到了每个重复单元带有2个炔基的聚合物主链.之后,利用高效的CuAAC反应,将末端带有叠氮基团的聚环氧乙烷(PEO)或聚苯乙烯(PS)侧链接枝到主链上,用核磁共振氢谱(1H-NMR)和体积排阻色谱(SEC)等对聚合物刷的结构进行表征.     

基于聚烯烃和聚苯乙烯的梳形(共)聚合物的研究进展

无论从生物大分子还是合成高分子,均表明大分子链拓扑结构对于材料性能具有重要的作用。探索聚合物分子链拓扑结构与材料性能的关系一直是高分子材料科学研究的重要课题。活性/可控聚合技术为特定拓扑结构的分子链(如:梳形聚合物)设计合成提供了有效途径,进而可以方便地调控聚合物的分子结构及其性能。针对梳形聚合物的合成,目前主要采用三种合成策略,分别是"Graft onto"策略、"Graft through"策略和"Graft from"策略。结合作者课题组的工作,本文综述了以聚烯烃和聚苯乙烯为基础的梳形(共)聚合物的可控合成以及结构与性能关系的研究进展,重点阐述了长链支化结构参数(支链长度、支链密度和化学组成)对于聚合物熔体行为、发泡行为和结晶行为的影响规律。     

机理转移法合成星形梳状聚丁二烯-g-聚甲基丙烯酸甲酯共聚物的研究

结合活性负离子聚合与原子转移自由基聚合(ATRP),采用机理转移法制备了一系列窄分布且分子量可控的星形梳状聚丁二烯-g-聚甲基丙烯酸甲酯接枝共聚物(SC-(PB-g-PMMA)).首先通过阴离子聚合,制备星形聚丁二烯,后经甲酸-过氧化氢原位环氧化对链中部分双键进行环氧化,再与原位生成2-溴异丁酸发生酯化反应,得到具有链中活性溴的星形大分子引发剂(SPB-Brn).然后,利用该大分子引发剂,采用CuCl/CuCl2/PMDETA催化体系,通过ATRP聚合单体MMA,合成出星形梳状SC-(PB-g-PMMA)聚合物.通过GPC,1H-NMR和FTIR等分析手段对合成的星形大分子引发剂及星形梳状聚合物进结构表征,证实得到目标产物,并同时研究了聚合物的热力学性质与溶液性质.     

原子转移自由基法合成4-(4′-甲氧基苯基甲亚胺)苯酚功能化的六臂星型聚苯乙烯

星型聚合物由于其独特的构型及其粘弹性能使其可能在交联剂,离子交换聚合物,表面活性剂,增容剂,热塑性弹性体等方面得到广泛的应用.星型聚合物按其链结构可以分为,星型(嵌段)聚合物[1],星型-支化聚合物[2],星型-梳状聚合物[3].星型聚合物的合成始于20世纪50年代活性负离子聚合[     

含mPEG侧链的水溶性梳状聚合物的合成及其侧链受限结晶行为研究

采用大单体与小单体共聚的技术,通过自由基引发溶液聚合,合成了一系列水溶性梳状聚合物———聚丙烯酸接枝聚乙二醇单甲醚(PAA-g-mPEG).制备过程分两步进行,首先合成大单体聚乙二醇单甲醚丙烯酸酯,然后将大单体与丙烯酸单体共聚,合成了梳状聚合物.通过控制反应条件,获得了一系列主链和支链组成比不同的接枝共聚物.用傅立叶变换红外光谱(FT-IR)和核磁共振氢谱(1H-NMR)表征了共聚物的结构,并对其侧链的结晶行为进行了研究.采用差热扫描量热法(DSC)表征并分析了不同侧链长度的mPEG的热性能及其结晶情况.利用相差显微镜和原子力显微镜(AFM)观察薄膜的结晶形貌,表明梳状聚合物的侧链mPEG在受限条件下的薄膜结晶形貌为高度支化的晶体,初步分析了mPEG链长及其在共聚物中的重量百分含量对晶体形貌的影响.     

梳形支化聚苯乙烯模型化合物的合成及表征

本文用阴离子聚合的聚苯乙烯进行氯甲基化,再将此带有活泼氯的甲基化聚苯乙烯作为主链与活性聚苯乙烯阴离子偶合接枝,制备了12个具有等长度支链沿主链无规分布的、结构明确的梳形聚苯乙烯模型化合物,并用GPC—粘度计联用装置对之进行了表征.     

侧链为端羧基聚乙二醇的梳形聚氨酯的合成与表征

以L-赖氨酸、乙二胺和端羧基聚乙二醇(PEG)为原料合成一种带聚乙二醇侧链的二元胺扩链剂(Lys-NH-PEG),然后以4,4'-二苯基甲烷二异氰酸酯(MDI)和Lys-NH-PEG为硬段,聚碳酸酯二醇(PCD)为软段,制备一种含端羧基聚乙二醇侧链的梳形聚氨酯.对所合成聚氨酯材料进行傅立叶变换红外光谱(FTIR)、氢核磁共振谱(1H-NMR)、凝胶渗透色谱(GPC)测试,测试结果表明得到了目标聚合物.该聚合物能在水中形成胶体,并能化学接枝白蛋白,表明所合成的聚氨酯的PEG侧链端羧基具有反应活性.这种具有可反应性的聚氨酯为进一步接枝生物分子以提高生物相容性提供了广阔的空间.     

梳形接枝共聚物的合成(Ⅱ)——载体化钌卡宾络合物催化降冰片烯基聚苯乙烯的开环岐化聚合

由石油化工副产C₅馏份提取双环戊二烯(DCPD)、以聚合物负载三氟化硼为催化剂进行DCPD与烯丙基氯(AC)的Diels-Alder反应合成5-氯甲基-2-降冰片烯(NBCH₂Cl),经锂代反应后用以引发苯乙烯的活性阴离子聚合合成了降冰片烯(NB)基聚苯乙烯(PS)大分子环烯单体NB-PS,在聚合物负载钌卡宾络合物[RuCl₂(PPh₃)₂(=C=CHtBu)]催化(引发)作用下进行大分子单体NB-PS的开环歧化聚合(ROMP)合成了梳形接枝共聚物PNB-g-PS.实验结果表明所合成聚合物负载硼、钌络合物催化剂的性能均明显优于对应非负载体.讨论了上述催化剂的聚合物载体效应的机理及温度、溶剂等对活性阴离子聚合反应的影响.     

Synthesis of a novel centipede-like copolymer of styrene and methyl methacrylate

A well-defined,A2B-type,centipede-like copolymer of styrene and methyl methacrylate(PS-PS-PMMA) was synthesized by the combination of living anionic polymerization and atom transfer radical polym-erization(ATRP) . The synthetic approach involves the coupling reaction of polystyrene(PS) backbone bearing 1,1-diphenylethene(DPE) pendant groups,produced by ATRP and Wittig reaction,with living polystyryllithium(PSLi) ,and subsequent polymerization of the resulting 1,1-diphenylmethyl anions with methy methacrylate. The centipede-like copolymer was characterized by 1H NMR,IR,SEC,SLS,and DSC measurements.     

Synthesis and characterization of a novel well-defined comb-like ionomer

A novel well-defined comb-like ionomer with cations was synthesized by the combination of living anionic polymerization and atom transfer radical polymerization (ATRP). The synthetic approach involves the coupling reaction of polystyrene (PS) backbone bearing 1,1-diphenylethene (DPE) pendant groups with living polystyryllithium (PSLi), subsequent amine functionalization of the resulting 1,1-diphenylmethyl anions with 3-dimethylaminopropyl chloride (DMAPC), and quaternization of tertiary amino groups with hydrochloric acid. The comb-like ionomer was characterized by ¹H NMR, IR, GPC measurements and end-group titrition.     

Quantitative amine functionalization of polymeric organolithium compounds with 3‐dimethylaminopropyl chloride in the presence of lithium chloride

The addition of lithium chloride promoted the coupling reaction of hydrocarbon solutions of poly(styryl)lithium (PSLi) and poly(isoprenyl)lithium (PILi) with 3‐dimethylaminopropyl chloride to form the corresponding ω‐dimethylamino‐functionalized polymers. Quantitative amine functionalization was achieved for PSLi and PILi in the presence of 1 and 10 equivalents, respectively, of LiCl in benzene; the functionalization efficiency was only 67% for PSLi and 85% for PILi in the absence of LiCl. The polymer products were characterized by size exclusion chromatography, thin‐layer chromatography, and amine end‐group titration. The pure amine‐functionalized polymers were isolated by silica gel column chromatography. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 145–151, 2000     

Synthesis and kinetic analysis of DPE controlled radical polymerization of MMA

The 1,1‐diphenylethene (DPE) controlled radical polymerization of methyl methacrylate was performed at 80 °C by using AIBN as an initiator and DPE as a control agent. It was found that the molecular weight of polymer remained constant with monomer conversion throughout the polymerization regardless of the amounts of DPE and initiator in formulation. To understand the result of constant molecular weight of living polymers in DPE controlled radical polymerization, a living kinetic model was established in this research to evaluate all the rate constants involved in the DPE mechanism. The rate constant k₂, corresponding to the reactivation reaction of the DPE capped dormant chains, was found to be very small at 80 °C (1 × 10^?5 s^?1), that accounted for the result of constant molecular weight of polymers throughout the polymerization, analogous to a traditional free radical polymerization system that polymer chains were terminated by chain transfer. The polydispersity index (PDI) of living polymers was well controlled <1.5. The low PDI of obtained living polymers was due to the fact that the rate of growing chains capped by DPE was comparable with the rate of propagation. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2009     

原子转移自由基聚合及可控自由基聚合

以作者在原子转移自由基聚合领域的研究成果为主导,结合国内外文献,对近年来出现的颇具影响的可控自由基聚合体系与进行了评述与展望。     

Tethering hydrophilic polymer brushes onto PPESK membranes via surface-initiated atom transfer radical polymerization

Surface-initiated atom transfer radical polymerization (ATRP) was used to graft hydrophilic comb-like poly((poly(ethylene glycol) methyl ether methacrylate), or P(PEGMA), brushes from chloromethylated poly(phthalazinone ether sulfone ketone) (CMPPESK) membrane surfaces. Prior to ATRP, chloromethylation of PPESK was beforehand performed and the obtained CMPPESK was prepared into porous membranes by phase inversion process. It was demonstrated that the benzyl chloride groups on the CMPPESK membrane surface afforded effective macroinitiators to graft the well-defined polymer brushes. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) confirmed the grafting of P(PEGMA) chains. Water contact angle measurements indicated that the introduction of P(PEGMA) graft chains promoted remarkably the surface hydrophilicity of PPESK membranes. The effects of P(PEGMA) immobilization on membrane morphology, permeability and fouling resistance were investigated. It was found that the comb-like P(PEGMA) grafts brought smaller pore diameters and higher solute rejections to PPESK membranes. The results of dynamic anti-fouling experiments showed the anti-fouling ability of the membranes was significantly improved after the grafting of P(PEGMA) brushes.     

双烯化合物类单体合成支化聚合物的支化结构的研究

分别以二乙烯基苯(DVB)、双甲基丙烯酸二缩三乙二醇酯(tri-EGDMA)和1,6-双马来酰亚胺基正己烷(BMIH)为支化单体,采用原子转移自由基聚合合成支化聚苯乙烯;以先核后臂法合成的星状支化聚苯乙烯为参照对合成的支化聚合物的支化形态进行研究.采用气相色谱(GC)、核磁共振氢谱(1H-NMR)和三检测凝胶渗透色谱(TD-SEC)测定了苯乙烯的转化率,聚合物分子量及其分布,特性黏数和均方回转半径.实验结果表明3个支化聚合反应体系内悬垂双键是逐步消耗的,不存在明显的成核过程.反应前期,以形成带有悬垂双键的初级链和轻度支化聚合物为主,聚合物分子量随单体转化率逐步上升;反应后期,悬垂双键聚合导致的分子之间的偶合更加明显,使得聚合物分子量快速上升,合成得到的都是无规支化聚合物.     

Synthesis and Characterization of Star-branched Polyisobutylene by Combination of Anionic Polymerization and Cationic Polymerization

The construction of polymer materials with controlled compositions, topologies, and functionalities has been the enduring focus in current research1,2. Among them, star polymers have been extensively studied for a long time, due to their markedly lower so…     

AB_2型星形杂臂偶氮液晶聚合物的合成及表征

通过原子转移自由基聚合(ATRP)与ATRP衍生物化学修饰结合的方法,合成了一系列AB2型星形杂臂偶氮液晶聚合物.其中,A为聚苯乙烯,B为聚6-[4-(4′-甲氧基苯基)偶氮苯氧基己酯](PMMAZO).合成分三步进行.首先,以ATRP方法得到ω-溴聚苯乙烯活性链PS(Br).然后对PS(Br)进行化学改性,得到带两个末端溴原子的聚苯乙烯活性链PS(Br)2·最后,以PS(Br)2作为双官能团大分子引发剂,引发6-[4-(4′-甲氧基苯基)偶氮苯氧基]己酯(MMAZO)发生ATRP聚合,得到星形杂臂PS(PMMAZO)2聚合物.进一步对聚合产物进行了GPC和1H-NMR分析.结果表明合成产物是预期的星形杂臂聚合物,产物分子量可控且分子量分布狭窄.同时,以DSC和POM表征了星形杂臂聚合物的液晶性.     

Synthesis and characterization of PEGylated comb-like cationic polymer by polycondensation and ATRP

PEGylated poly(2-(dimethylamino)ethyl methacrylate) with comb-like architecture was synthesized by two-step polymerization. First,poly(oligo(ethylene glycol) malicate)(POEGMA) bearing pendant hydroxyl groups was prepared by direct polycondensation of oligo(ethylene glycol) and malic acid in the presence of scandium triflate as chemoselective catalyst.Then the poly(2- (dimethylamino)ethyl methacrylate) side chains were grafted from the POEGMA backbone by atom transfer radical polymerization (ATRP) after the hydroxyl groups were modified into bromo-ester form,resulting in a PEGylated cationic copolymer with branched architecture.