Evaluation of the clenbuterol imprinted monolithic column prepared by reversible addition-fragmentation chain transfer polymerization

做更多的同质的器官的整体的结构，可逆增加破碎链转移(木排) 过程在 clenbuterol 的合成被采用印的聚合物。在合成，聚合物结构和分离效率上的合成条件的影响被学习。结果证明与椽子过程准备的印的柱比在礼品与常规聚合准备的柱让更高的柱效率和选择学习，它可以源于更高的表面区域，更小的毛孔尺寸和更狭窄的水珠在他们的结构的尺寸分发。如果为 clenbuterol 的更好的条件印了整体的聚合物准备，结果显示了那木排聚合。

Synthesis of polystyrene-styrene/butadiene diblock copolymers via reversible addition-fragmentation chain transfer miniemulsion polymerization

Polystyrene-styrene/butadiene diblock copolymers were synthesized via reversible addition-fragmentation chain transfer （RAFT） miniemulsion polymerization.During the polymerization process,the molecular weight distribution was narrow and the numerical molecular weight of the copolymers increased with increasing conversion of monomers,which was close to the theoretical.FT-IR and ^1H NMR results indicated that the microstructure of the polymer was mainly 1,4-trans-butadiene with small amount of 1,2-units,and composition in the copolymers was obtained.

Reversible addition-fragmentation chain transfer graft polymerization of acrylonitrile onto PE/PET composite fiber initiated by γ-irradiation

Reversible addition-fragmentation chain transfer(RAFT) mediated grafting of acrylonitrile onto Polyethylene/Poly(ethylene terephthalate)(PE/PET) composite fibers was performed using γ-irradiation as the initial source at ambient temperature. Different initial concentrations of 2-cyanoprop-2-yl dithiobenzonate were used as the chain transfer agent. The kinetics of graft polymerization is in accordance with the living RAFT polymerization. The successful grafting of acrylonitrile is proved by Fourier transform infrared spectroscopy analysis.The results of monofilament tensile test show that mechanical properties of the fibers change slightly after grafting. Scanning electronic microscopy images of the fibers show that the surface of RAFT grafted fibers is smoother than that of fibers grafted conventionally.

Grafting of MIPs from PVDF Membranes via Reversible Addition-fragmentation Chain Transfer Polymerization for Selective Removal of p-Hydroxybenzoic Acid

Effective molecularly imprinted membranes（MIMs） were developed as an efficient adsorbent for the selective removal ofp-hydroxybenzoic acid（p-HB） from acetylsalicylic acid（ASA, aspirin）. The MIMs were grafted successfully from poly（vinylidene fluoride） microfiltration membranes via reversible addition-fragmentation chain transfer（RAFT） polymerization. The graft copolymerization of acrylic acid（AA） in the presence of template p-hydroxybenzoic acid led to molecularly imprinted polymer（MIP） film coated membranes. The obtained MIMs were characterized by scanning electron microscopy（SEM）, Fourier transform infrared spectrophotometer（FTIR） and Raman spectra, and batch mode adsorption studies were carried ont to investigate the specific adsorption equilibrium, kinetics and selective recognition properties of different MIMs. The kinetic properties of the MIMs could be well described by the pseudo-second-order rate equation. Selective permeation experiments were performed to evaluate the permeation selectivity of the p-HB imprinted membranes. The observed performances of the MIMs are applicable to the further purification of aspirin. Keywords Acetylsalicylic acid; Reversible addition-fragmentation chain transfer; Molecularly imprinted membrane; p-Hydroxybenzoic acid; Selective adsorption

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.

Molecularly Imprinted Polymers on Chloromethyl Polystyrene Resin Prepared via RAFT Polymerization

Surface molecularly imprinted polymers （SMIP） was prepared via the reversible addition-fragmentation chain transfer （RAFT） polymerization on the chloromethyl polystyrene resin （CPR） in the presence of the template D-phenylalanine. The structure of SMIP was characterized by FTIR and SEM. The adsorption behavior of D-phenylalanine of SMIP was preliminarily investigated.

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.

Reversible Chain Transfer Catalyzed Polymerization with Alkyl Iodides Generated from Alkyl Bromides by in Situ Halogen Exchange

Reversible chain transfer catalyzed polymerization(RTCP)is a practical and efficient process for the precise synthesis of polymers with special architecture by using simple phenols(2,4,6-trimethylphenol,TMP)or hydrocarbons(xanthene,XT)as efficient organocatalysts.Herein,alkyl iodide(R-1),which was gen erated from in situ bromine-iodine transformation of alkyl bromide(R-Br)with sodium iodide(Nal),was served as initiator to mediate RTCP with TMP or XT.MMA and other functional methacrylates,including GMA,DEAM,DMAEMA and BzMA,were successfully initiated by combining orga no catalysts and azo in itiators to yield polymers with low-polydispersity(M_(w)/M_(n)=1.1-1.5)and ideal mono mer conversions(50%-90%)at moderate temperature.More over,3-armstar polymers were also obtained by this method.The high chain-end fidelity of the obtained poly(methyl methacrylate)with iodine as chain-end group(PMMA-I)was confirmed by chain-extension reaction.The en vironme ntally frie ndly initiators and orga no catalysts exhibit powerful polymerization properties toward RTCP,providing a sign ificant method to synthesize functional polymers.

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。

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.

Degradable and Recyclable Polymers by Reversible Deactivation Radical Polymerization

Reversible deactivation radical polymerization(RDRP)provides unprecedented control over polymer composition,size,functionality,and topology.Various materials,such as linear polymers,star polymers,branched polymers,graft polymers,polymer networks,and hybrid materials,have been prepared by RDRP.The ability to control polymer topology also enabled precision synthesis of well-defined polymer topologies with degradable functional groups located at specific locations along a polymer chain.This review outlines progress in the synthesis of degradable polymers designed by RDRP,organized by topology and synthetic route.Recent progress in the depolymerization of polymers using RDRP mechanisms is highlighted and critically discussed.

RAFT聚合法合成苯乙烯/乙烯水杨醛嵌段共聚物及其自组装

以末端含有三硫酯结构的聚苯乙烯(PS-DMAT)为大分子链转移剂,AIBN为引发剂,在65℃下四氢呋喃(THF)中成功实现了苯乙烯(St)与乙烯基水杨醛(HVB)的“活性”/可控RAFT自由基嵌段共聚合。通过凝胶渗透色谱(GPC)对产物的分子量进行了分析,结果表明合成聚合物数的均分子量(Mn)基本上随乙烯基水杨醛(HVB)单体转化率的增加而线性地增加,在整个反应过程聚合物均保持较窄的的分子量分布(Mw/Mn<1.30),聚合过程呈现出自由基共聚合可控特征。利用核磁共振氢谱(1HNMR)对嵌段共聚物聚苯乙烯-b-聚乙烯水杨醛(PS-b-PHVB,Mn=15300,Mw/Mn=1.18)进行了表征,确定了其结构及组成。此外,通过动态光散射仪(DLS)和扫描电子显微镜(SEM)研究了嵌段共聚物在四氢呋喃(THF,共溶剂)和乙醇(EtOH,选择性溶剂)的混合溶剂中的自组装行为,结果表明,当THF/EtOH体积比为4/6、5/5、6/4时,嵌段聚合物能够形成形状规则、平均粒径在200~300 nm左右的球形胶束。

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。

磺化木质素基链转移剂的合成及其在水相RAFT聚合中的应用

以玉米秸秆木质素为原料,将木质素磺化改性,再利用二硫化碳、溴乙酸甲酯对磺化木质素(SL)进行黄原酸酯功能化改性,合成了磺化木质素基链转移剂(SL-CTA),之后将其用于丙烯酰胺的水相RAFT聚合反应制备磺化木质素-丙烯酰胺共聚物(SL-g-PAM),并采用多种方法对链转移剂及共聚物进行表征。研究结果表明:相比于磺甲基化改性,芳基磺化改性的效果更好,当1 g木质素与2 g氯磺酸在25℃下反应4 h时,改性效果最佳,此时磺化木质素含S量为1.83%,M_(w)/M_(n)为1.19,含总羟基量为4.86 mmol/g,且水溶性良好。FT-IR、^(13)C NMR对磺化木质素基链转移剂的结构表征结果发现:红外谱图显示900 cm^(-1)处出现C—S伸缩振动吸收峰及1738 cm^(-1)处出现C O特征峰,^(13)C NMR谱图中δ172处出现了C S的碳原子峰,共同证明了SL-CTA的成功合成。探究丙烯酰胺的水相RAFT聚合体系中单体/链转移剂/引发剂比例、pH值及反应温度对单体转化率的影响,结果表明:单体/链转移剂/引发剂物质的量之比为500∶4∶1、pH值5、70℃下反应4 h时转化率高达98.5%。该实验条件下,聚合反应一级动力学曲线呈现了较好的线性关系,所得聚合物的相对分子质量与转化率也基本呈现一次线性关系,同时其多分散系数较低且分布相对较窄(1.13~1.43),证明了反应具有较高的可控性。

热可逆黄原酸酯链转移剂制备及在VDF聚合中的应用

可逆加成-断裂链转移聚合(RAFT)具有聚合物分子量可控且分子量分布较窄的特点,但目前RAFT聚合聚偏氟乙烯(PVDF)调控用链转移剂比较单一。为得到性能更加优异的PVDF基聚合物,采用Diels-Alder反应等方法制备了一种含有动态共价键的新型RAFT聚合用链转移剂,并成功用于偏氟乙烯(VDF)的活性可控聚合。首先,合成得到具有热可逆性质的呋喃保护的马来酰亚胺基黄原酸酯链转移剂(XCTA),通过核磁共振氢谱(1H NMR)确定XCTA的结构。将该XCTA用于VDF的RAFT聚合,经过处理后对聚合物结构以及分子量进行表征和测试,确定得到了含动态共价键的PVDF基聚合物,且XCTA成功实现对VDF的活性调控,得到的PVDF多分散性指数在1.3以下,其远低于普通自由基聚合得到的PVDF。利用XCTA制备的聚合物仍有活性,可继续用于合成性能更加优异的PVDF基嵌段共聚物等,为下一步制备PVDF基多功能聚合物提供了新的思路。

基于星型单体与RAFT相结合的超支化聚合物的合成与评价

为改变线性聚合物分子链长,高温下易剪切断链,抗温抗盐能力不足等缺点,在单体及组成一定的情况,通过改变聚合物的分子构象,采用可逆加成-断裂链转移聚合(RAFT)法,基于星型单体与RAFT相结合制备得到黏度效应低、抗温抗盐能力强的超支化聚合物EHBPS-P。性能评价结果表明,EHBPS-P抗温可达220℃,加入超支化聚合物的基浆在220℃老化后黏度降低率为66.7%(同组分线性聚合物黏度降低率达90.98%),淡水、盐水、复合盐水基浆中加量为1.0%(质量分数)时,可使钻井液的滤失量控制在10.0 mL以内,优于线性聚合物,有较好持续抗温性和长效的作用周期。

马来酸酐和苯乙烯的可逆加成-断链链转移聚合及新型嵌段共聚物的合成

Reverse addition\|fragmentation chain transfer (RAFT) polymerizatin of MAn with St is reported aiming at the synthesis of a well\|defined alternating copolymer of MAn with St.The results show that the polymers possess predetermined molecular weight and molecular weight distribution as narrow as 1 2. A novel well\|defined block copolymer P(MAn\| alt \|St)\| b \|PSt has also been prepared by the copolymerization of MAn with excess amount of St in molar feed via RAFT process.

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.

“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。