Aggregation-induced emission polymers via reversible-deactivation radical polymerization Special Collection:Distinguished Australian Researchers

Aggregation-induced emission(AIE)is a unique phenomenon whereby aggregation of molecules induces fluorescence emission as opposed to the more commonly known aggregation-caused quenching(ACQ).AIE has the potential to be utilized in the large-scale production of AIE-active polymeric materials because of their wide range of practical applications such as stimuli-responsive sensors,biological imaging agents,and drug delivery systems.This is evident from the increasing number of publications over the years since AIE was first discovered.In addition,the evergrowing interest in this field has led many researchers around the world to develop new and creative methods in the design of monomers,initiators and crosslinkers,with the goal of broadening the scope and utility of AIE polymers.One of the most promising approaches to the design and synthesis of AIE polymers is the use of the reversible-deactivation radical polymerization(RDRP)techniques,which enabled the production of well-controlled AIE materials that are often difficult to achieve by other methods.In this review,a summary of some recent works that utilize RDRP for AIE polymer design and synthesis is presented,including(i)the design of AIE-related monomers,initiators/crosslinkers;the achievements in preparation of AIE polymers using(ii)reversible addition–fragmentation chain transfer(RAFT)technique;(iii)atom transfer radical polymerization(ATRP)technique;(iv)other techniques such as Cu(0)-RDRP technique and nitroxide-mediated polymerization(NMP)technique;(v)the possible applications of these AIE polymers,and finally(vi)a summary/perspective and the future direction of AIE polymers.

基于光引发可逆加成断裂链转移自由基聚合的3D打印

针对高分子化学本科教学中“活性自由基聚合”知识点抽象,学生难以理解的教学难题,开展了光引发可逆加成断裂链转移(RAFT)自由基聚合3D打印实验。实验首先合成O-(乙基)-S-(2-丙酸乙酯基)黄原酸酯(EXEP),随后使用商用光敏树脂,进行添加/不添加EXEP条件下的3D打印。随后使用得到的打印体开展荧光功能后修饰与焊接对比实验。通过对比实验现象,深入理解活性自由基聚合机理及其对产物后功能化能力的影响,实现“活性自由基聚合”原理的“可视化”和实例化应用展示。本实验将基础理论有机融合到趣味实验中,实验耗时合理,操作简便,效果明显,符合本科教学实验基本要求,有助于提升学生综合分析能力,激发学生深入研究的兴趣,培养其创新意识及拓展延伸的能力。

基于一磷酸腺苷的RAFT接枝棉织物的结构和阻燃性能

采用可逆加成断裂链转移自由基聚合(RAFT)方法,基于纤维基二硫代酸酯类RAFT链转移剂(Cell-CTA),以偶氮二异丁腈为引发剂,以改性一磷酸腺苷(AAMP)为阻燃单体,在纯棉织物上进行RAFT接枝聚合改性,制备了接枝阻燃棉织物(Cell-g-PAAMP)。采用红外光谱、扫描电镜、拉曼光谱等方法对Cell-g-PAAMP的化学结构、表面形貌及其燃烧后残炭的形态和石墨化程度进行了表征。采用热重分析仪、数显氧指数测定仪、织物强力仪、透气性能测试仪对Cell-g-PAAMP的阻燃性能和物理机械性能进行了分析。Cell-g-PAAMP红外光谱中,1199 cm^(-1)处新出现P=O双键的伸缩振动峰,说明已成功制备Cell-g-PAAMP。扫描电镜和拉曼光谱结果表明,Cell-g-PAAMP表面粗糙,有颗粒状物质附着于表面,燃烧后残炭形态保持基本完整且结构致密,石墨化程度提高。与纯棉织物对比,Cell-g-PAAMP初始分解温度降低,热稳定性提高,极限氧指数提高,获得了良好的阻燃效果。Cell-g-PAAMP透气性和断裂强力下降,但断裂伸长率却大幅增加。

Synthesis of Thermoresponsive Poly( diethyleneglycol methacrylate-co-6-Ovinyladipoyl-D-glucopyranose) Glycopolymer via RAFT Polymerization

The monomer 6-O-vinyladipoyl-D-glucopyranose( VAG)was synthesized by lipase catalyzed trans-esterification of divinyladipate with D-glucopyranose. A novel double hydrophilic glycopolymer poly( diethyleneglycol methacrylate-co-6-Ovinyladipoyl-D-glucopyranose)( P( DEGMA-co-VAG)) with narrow polydispersity( PDI) and thermosensitivity was prepared by reversible addition-fragmentation chain transfer( RAFT)polymerization. P( DEGMA-co-VAG) was characterized by1 H NMR,FTIR and gel permeation chromatography( GPC). The characterization of UV-visible spectroscopy showed that the micelles from glycopolymer P( DEGMA-co-VAG) were thermo-responsive and the low critical solution temperature( LCST) could be controlled by the molar ratio of monomers. When the molar ratio of DEGMA and VAG was 2∶ 1,the LCST of P( DEGMA-co-VAG) was36 ℃ in aqueous solution,which could form nano micelles in the human body environment. It was found that P( DEGMA-co-VAG)was non-toxic at 0. 1-1 mg / m L concentrations when incubated with pig iliac endothelial cells( PIECs) for 24 h. Thus,the synthesized glycopolymers has great potential as drug delivery carriers.

Simulation of Rate Retardation in RAFT Polymerization of Styrene with Low RAFT-Initiator Ratio

Bulk polymerizations of styrene (St) were carried out in the presence of three reversible addition fragmentation chain transfer (RAFT) agents benzyl dithiobenzoate (BDB), cumyl dithiobenzoate(CDB), and 1-phenylethyl dithiobenzoate (PEDB) under low ratio of RAFT agent to initiator. The kinetic model was developed to predict polymerization rate, which indicates that the RAFT polymerization of St is a first-order reaction. In the range of experimental conversions, the plots of -ln(1-x) against time t are approximately linear (x is monomer conversion). The kinetic study reveals the existence of strong rate retardation in RAFT polymerization of styrene. A coefficient K_r is defined to estimate the rate retardation in the RAFT system considering the assumption that the retardation in polymerization rate is mainly attributed to slow fragmentation of the intermediate radicals. K_r relates to the structure of RAFT agents as well as the concentrations of RAFT agent and azobis isobutyronitrile (AIBN). For a certain RAFT agent, the value of K_r is enhanced by the increase in the initial concentration of RAFT agent and the higher ratio of RAFT to AIBN. With the same recipe for different RAFT agents, the increasing trend for the values of K_r is BDB<PEDB<CDB.

基于点击化学和可逆加成-断裂链转移自由基聚合合成极性链接枝聚丁二烯

以1-硫代甘油作为改性剂、聚丁二烯为主链,通过热引发和光引发合成了侧基含有羟基的聚丁二烯,以S-1-十二烷基-S′(α-α′-二甲基-α′′乙酸)-三硫代碳酸酯作为可逆加成-断裂链转移自由基聚合试剂、偶氮二异丁腈为引发剂,合成了端羧基聚N,N-二甲基丙烯酰胺,然后将两种官能化的聚合物进行酯化反应制得聚N,N-二甲基丙烯酰胺接枝聚丁二烯。结果表明,采用光引发可以显著提高点击化学的反应效率。用核磁共振氢谱证实了产物含羟基聚丁二烯和端羧基聚N,N-二甲基丙烯酰胺以及接枝聚合物的结构,并显示通过这种方法所制备接枝聚合物的接枝链数目和长度均可控。

Mechanism study and molecular design in controlled/“living” radical polymerization

This tutorial review summarizes recent progress in the research field of controlled/"living" radical polymerization (CLRP) from Soochow University.The present paper gives a broad overview of the mechanism study and molecular design in CLRP.The mechanism study in CLRP aided by microwave,initiated by γ-radiation at low temperature,mediated by iron,in reversible addition-fragmentation chain transfer (RAFT) polymerization and the mechanism transfer between different CLRP processes are reviewed and summarized.The molecular design in CLRP,especially in RAFT polymerization for mechanism study,and in achieving tailor-made functional polymers is studied and discussed in the later part.

Recent advances in “living”/controlled radical polymerization of phosphorus-containing monomers and their potential applications

Special research attention has been paid to phosphorus-containing materials and their corresponding applications. This mini review considers recent publications devoted to the "living"/controlled radical(co)polymerization of phosphorus-containing monomers. In addition, different properties of the polymers involved in the phosphonate group in various chemical environments are demonstrated, and their potential applications are briefly discussed.

Molar Mass Dispersity Control by lodine-mediated Reversibledeactivation Radical Polymerization

Dispersity(D)of polymers has a great effect on the properties of polymeric materials,and therefore how to control θ is very important but still a huge challenge in polymer synthesis,especially for reversible-deactivation radical polymerization(RDRP)strategy.Herein,we successfully developed a novel strategy to adjust D of polymers by visible light-controlled reversible complexation mediated living radical polymerizatio n(RCMP)and combi nation of single-electron transfer-degenerative chain tran sfer living radical polymerization(SET-DTLRP)at room temperature.In RCMP system,2-iodo-2-methylpropionitrile(CP-I)and ethyl 2-iodo-2-phenylacetate(EIPA)were used as alkyl iodide initiators,by using methyl methacrylate(MMA)as the model monomer and n-butylacrylate(BA)as the end-capping reagent to regulate D of polymers.Subsequently,we successfully prepared the block copolymer PMMA-b-PBA with adjustable D by reactivating the polymer end-chains via SET-DTLRP in the presence of copper wire,fully dem on strati ng that it is a promising strategy that can keep the"living"feature of polymers while regulating their molar mass dispersities easily.

用双硫酯链转移法合成嵌段聚合物

研究了以双硫酯为链转移剂进行的均聚和嵌段共聚物的合成 .首先合成大分子链转移剂 ,得到分子量可控、多分散性系数较小的均聚物PMMA、PBMA、PEMA、PEA、PBA、PMA、PSt,多分散性系数一般小于 1 30 .在相同的条件下 ,甲基丙烯酸酯类的聚合速度最快 ,苯乙烯其次 ,丙烯酸酯类最慢 .用末端带有双硫酯基团的PSt、PBMA、PBA为链转移剂 ,加入多种第二单体聚合得到实测分子量与理论分子量接近 ,且多分散性系数较小的两嵌段聚合物 .在链转移剂和引发剂的比例为 3∶1～ 6∶1的范围内 ,聚苯乙烯同样可以作为第一嵌段得到和其它酯类单体的两嵌段聚合物 .1 H NMR方法证明了聚合物的末端带有双硫酯基团 .嵌段聚合时必须加入微量的自由基引发剂以形成大分子自由基 。

以双硫酯为链转移剂的活性自由基聚合

合成并研究了两种双硫酯链转移剂的纯化方法 ,进行了多种单体以双硫酯为链转移剂的活性自由基聚合及嵌段共聚 .发现以PhC(S)SC(CH3) 2 Ph为链转移剂的效果比PhC(S)SCH(CH3)Ph好 ,聚合产物的多分散性系数较小 .引发剂与链转移剂的摩尔数比为 1∶3 5～ 1∶4 2时 ,得到多分散性系数小 ,实测分子量与理论分子量相近的聚合产物 .聚合物的分子量随时间和转化率的增加而增加 ,加入第二单体形成嵌段共聚物 ,具有活性聚合特征 .聚甲基丙烯酸酯大分子引发剂引发丙烯酸酯单体聚合时 ,聚合速度最快 .

可逆加成—断裂链转移活性自由基聚合

介绍了可逆加成 -断裂链转移 (Reversibleaddition fragmentationchaintransfer,RAFT)活性自由基聚合的反应机理、聚合动力学和特点 ,对RAFT试剂的选择和制备作了简要介绍 。

双硫酯为链转移剂的活性自由基水相聚合

在通常的自由基乳液聚合体系中加入双硫酯链转移剂 Ph C(S) SCH(CH3 ) Ph,研究了 3种酯类单体的活性自由基水相聚合。发现在引发剂与链转移剂的摩尔比为 1∶ 3.3～ 1∶ 4时 ,可得到多分散性系数小 (<1.3) ,实测分子量与理论分子量相近的聚甲基丙烯酸丁酯 (PBMA)、聚丙烯酸丁酯 (PBA)等聚合物 ;聚合物的分子量随时间和转化率的增加而增加 ,具有活性聚合特征 ;醋酸乙烯酯的聚合未得到理想产物。以偶氮二异丁腈 (AIBN)为引发剂时 ,合适乳化剂为 OP- 8(占单体量 10 % ) ;以 (NH4) 2 S2 O8引发时 ,合适乳化剂是十二烷基磺酸钠 (占单体量 2 .4 % )与聚乙烯醇 (PVA,占单体量 1% )的混合乳化体系。油溶性引发剂 AIBN具有较好的控制聚合效果。

“活性”/控制自由基聚合的研究进展

本文对“活性”/控制自由基聚合的研究进展做了综述 ,并讨论了其主要聚合引发体系的应用现状和前景。

“活性”/可控自由基聚合的研究进展

对聚合物分子的组成和结构进行精密控制是当前聚合物研究的重要领域 ,“活性” 可控自由基聚合可以对自由基聚合进行控制 ,其综合了自由基聚合和离子聚合的优点。本文介绍了实现“活性” 可控自由基聚合的 5种途径 ,认为利用“活性”

N-咔唑二硫代甲酸异丙苯酯的合成及应用

以咔唑和α-甲基苯乙烯为原料,合成了以咔唑为Z基团的可逆加成-断裂链转移试剂——N-咔唑二硫代甲酸异丙苯酯(CCBD),该化合物合成简便,可以经重结晶提纯.以CCBD为可逆加成-断裂链转移试剂对苯乙烯、甲基丙烯酸甲酯和丙烯酸乙酯单体进行了RAFT聚合,该聚合具有活性聚合特征,聚合物相对分子质量随转化率升高而增大,并得到相对分子质量分布窄的聚合产物,研究表明CCBD具有很好的RAFT聚合控制能力.

通过RATRP法在硅胶表面接枝两亲性嵌段聚合物

首先将叔丁基过氧化氢引到硅胶表面,然后,以氯化铜为催化剂,联二吡啶为配体,实现了甲基丙烯酸甲酯的反向原子转移自由基聚合,并以此杂化材料作为大分子引发剂,实现了丙烯酰胺的原子转移自由基聚合,得到了结构可控的硅胶-聚甲基丙烯酸甲酯-b-聚丙烯酰胺两亲性嵌段共聚物,并用XPS,GPC,SPM和TG等对其进行了表征与测试。结果表明,该反应体系符合"活性聚合"的特征。

水介质中可控活性自由基聚合的研究进展

综述了均相水溶液体系和分散、悬浮、乳液及微乳液等非均相水溶液体系中的可控 活性自由基聚合的研究现状。对一些最常见的可控自由基聚合方法 ,如氮氧调控聚合、原子转移自由基聚合和可逆加成 断裂链转移聚合方法的聚合情况进行了详细的介绍。展望了水介质中可控

窄分子量分布的聚丙烯酸的合成及其阻垢性能

以水为溶剂,采用可逆加成-断裂链转移自由基聚合(RAFT)方法,合成了分子量2400～9000的聚丙烯酸。GPC分析表明,所合成的聚丙烯酸具有很窄的分子量分布(多分散系数PDI约为1.2)。阻垢性能测定结果表明,用RAFT方法合成的聚丙烯酸比采用普通自由基聚合得到的商品聚丙烯酸阻垢剂具有更好的阻垢性能。如当分子量约为2400的聚丙烯酸的质量浓度分别为2和10mg/L时,其阻碳酸钙垢的阻垢率分别为83.8%和97.5%,而在相同质量浓度下商品聚丙烯酸阻垢剂的阻碳酸钙垢的阻垢率则仅分别为21.3%和42.9%。阻垢作用随温度升高(50～90℃)而降低的幅度也明显小于商品聚丙烯酸阻垢剂,80℃时二者的阻垢作用差别最大,而这正是一般冷却水达到的最高温度。在所研究的分子量范围内,所合成的聚丙烯酸分子量愈小则其阻垢性能愈好。

可逆加成-断裂链转移聚合研究进展

对可逆加成 断裂链转移 (RAFT)聚合的反应机理、可逆加成 断裂链转移剂的合成方法及其反应动力学的研究进展分别进行了综述。