SYNTHESIS OF POLYMERS WITH AMINO END GROUPS BY ATOM TRANSFER RADICAL POLYMERIZATION

Atom Transfer Radical Polymerization (ATRP) is a controlled radical polymerization process that produces polymers with predictable molecular weights, narrow polydispersities, and well-defined halogen end groups. The key factor in the control of the polymerization process is the presence of a metal/ligand complex that provides a fast, reversible activation and deactivation of the growing polymer chains. The ligands, used to complex the metal are mostly tertiary amino compounds. However, amines can interact with the halogen end groups of the initiator molecules or of the growing chains. Our investigations concern-ing this issue indicate that under the experimental conditions used during the polymerization process, interactions of end groups with tertiary amines are negligible. Ammonia and primary amines, e.g., n-butylamine, however can react with the halogen end groups. Moreover, after the polymerization reaction they can be used as nucleophilic agents to replace the halogens by other functional end groups. The use of difunctional molecules such as ethanolamine leads to the incorporation of alcohol end groups at the chain ends.     

SYNTHESIS OF AMPHIPHILIC COIL-ROD-COIL BLOCK COPOLYMERS USING ATOM TRANSFER RADICAL POLYMERIZATION

ABSTRACT

Coil-rod-coil block copolymers composed from luminescent rigid units and acrylate flexible blocks have been synthesized using atom transfer radical polymerization. α,ω-Difunctionalized oligophenylenes properly modified to act as ATRP initiators have been used for the polymerization of the various acrylates. Copolymers with controlled shape and in some cases, relatively low polydispersities have been obtained as proved by size exclusion chromatography and NMR. In cases, where t-butyl acrylate blocks have been used as the flexible part, selective hydrolysis resulted in coil-rod-coil copolymers containing poly(acrylic acid) blocks. The solution behavior of the synthesized copolymers was explored in various solvents. The poly(acrylic acid) copolymers in aqueous solutions form large aggregates, while in organic selective solvents for the flexible block, monomolecular micelles seem to be formed.     

ATRP法制备两亲性嵌段共聚物的研究

以α 溴代丙酸乙酯 (EPN Br)为引发剂、氯化亚铜 (CuCl)和联二吡啶 (bpy)组成的混合体系为催化剂 ,引发苯乙烯聚合 ,得到了端基为卤原子的单分散聚苯乙烯 (PS X)预聚体 .以此PS X为大分子引发剂、CuCl和N ,N ,N′ ,N″ ,N″ 五甲基二亚乙基三胺 (PMDETA) bpy的混合体系为催化剂 ,引发N ,N 二甲基丙烯酰胺(DMAA)聚合 ,得到了分子量分布较窄的聚苯乙烯 b 聚N ,N 二甲基丙烯酰胺 (PS b PDMAA)两亲性嵌段共聚物 .考察了大分子引发剂的分子质量、聚合介质及配位剂等对聚合过程的影响 .并用GPC、IR、1 H NMR等对产物进行了表征 .研究结果表明 ,该聚合反应体系符合原子转移自由基聚合的特征 .     

END GROUP TRANSFORMATION OF POLYMERS PREPARED BY ATRP,SUBSTITUTION TO AZIDES

Polystyrenes, polyacrylates and poly(methyl methacrylate) prepared by atom transfer radical polymerization (ATRP) have predictable molecular weights, low polydispersities and well-defined halogen end groups. The halogen end groups have been substituted by other functionalities such as azides and amines. In order to predict the feasibility and selectivity of nucleophilic substitution reactions, the reactivities of the end groups of the different polymers were studied. First, model studies with benzyl halide (BzX), 1-phenylethyl halide (1-PEX), methyl 2-halopropionate (MXP), ethyl 2-bromoisobutyrate (EBiB) and 2-halopropionitrile (2-XPN) were performed. The models compounds were dissolved in DMF and after adding sodium azide (1.1 eq.), the reaction mixtures were stirred at 25°C. The relative magnitude of the rate constants for the reactions with the chlorinated substrates were found to be BzCl > MClP > 1-PECl ≈ 2-ClPN:22 > 6 > 1. Increased substitution at the carbon center decreased the rate of reaction, benzyl chloride reacted 22 times faster than 1-phenylethyl chloride. The brominated substrates reacted very fast. The rate constant of 1-PEBr, determined by competition experiments, was 4.5 times higher than the rate constant of benzyl chloride. Based on these results, the bromine end groups of different polymers were substituted under reaction conditions simular to those used for the model reactions. The end-functionalized polymers were characterized by ¹H-NMR, IR and MALDI-TOFMS.     

α,α-二溴甲苯引发的苯乙烯原子转移自由基聚合研究

自从Ｍａｔｙｊａｓｚｅｗｓｋｉ等[1,2 ] 发现原子转移自由基聚合 (ＡＴＲＰ)以来 ,寻求新的双多官能引发剂是该领域的重要研究方向之一[3～ 7] .2 0 0 0年 ,我们[8]曾报道了α ,α 二溴乙酸乙酯可作为丙烯酸酯ＡＴＲＰ的双官能引发剂 ,并基于其两端增长的活性聚合性质合成了ＰＳ ｂ ＰＢＡ ｂ ＰＳ和ＰＭＭＡ ｂ ＰＢＡ ｂ ＰＭＭＡ两种三嵌段共聚物 .与此同时 ,Ｈｏｃｋｅｒ等[9] 通过比较氯化苄与α ,α 二氯甲苯引发的苯乙烯ＡＴＲＰ的聚合速度 ,认为α ,α 二氯甲苯是苯乙烯ＡＴＲＰ的双官能引发剂 .当我们参照上述结果 ,用α ,α 二…     

一种光学活性三嵌段共聚物的ATRP合成及表征

以溴代聚砜为大分子引发剂,三(2-二甲氨基乙基)胺(Me6TREN)/CuBr为催化体系,通过原子转移自由基聚合(ATRP)制备了结构预定且分子量分布窄的光学活性三嵌段共聚物,聚(N-甲基丙烯酰-L-亮氨酸甲酯)-嵌-聚砜-嵌-聚(N-甲基丙烯酰-L-亮氨酸甲酯)(PMALM-b-PSF-b-PMALM).通过核磁共振氢谱(1H-NMR)、凝胶渗透色谱(GPC)、端羟基滴定等方法,研究了所合成的三嵌段共聚物的结构.利用差示扫描量热法(DSC)、热失重分析(TGA)以及圆二色谱(CD)研究了嵌段共聚物的热性能和旋光性能.根据TGA计算出的PMALM链段与PSF链段的重复单元数之比,与1H-NMR计算的结果能较好的吻合.共聚物在聚合过程中旋光度发生了反转,且比单体的旋光度的绝对值显著增加,这可能是由于聚合过程中分子主链感应出了手性的二级结构诱导出手性放大效应引起的.在CH3OH/CCl4混合溶剂中,共聚物比旋光度的绝对值随溶剂极性增大呈线性减小趋势,这一结果与CD一起证实了PMALM链段的无规卷曲结构.     

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[     

N-取代马来酰亚胺和苯乙烯的原子转移自由基共聚合

近来,以卤代烷、铜（Ⅰ）卤素盐和２,２ 联吡啶体系引发苯乙烯可进行活性聚合,即原子转移自由基聚合（ＡＴＲＰ）,得到指定分子量和窄分子量分布的聚合物［１］,开辟了活性聚合的一个新领域,引起了广泛的关注．利用ＡＴＲＰ方法,对合成较窄的分子量分布的均聚物...     

原子转移自由基聚合制备聚(甲基丙烯酸甲酯-b-苯乙烯)时单体聚合顺序对嵌段效率的影响

采用原子转移自由基聚合研究了聚（ 甲基丙烯酸甲酯 ｂ 苯乙烯） 嵌段共聚物的合成,实验结果表明,当先进行甲基丙烯酸甲酯的聚合,然后再进行苯乙烯的聚合时,得到了完全的嵌段共聚物;反之,如果改变单体的聚合顺序,则嵌段效率很低．用聚合物末端Ｃ—Ｘ（Ｘ＝ Ｃｌ,Ｂｒ） 键的断裂能对实验结果进行了解释．     

THE ATOM TRANSFER RADICAL POLYMERIZATION OF LAURYL ACRYLATE

The atom transfer radical polymerization (ATRP) of dodecyl (or lauryl) acrylate (LA) has been studied and optimized to yield polymers with predetermined molecular weights and low polydispersities. The poor solubility of the catalyst complex formed with linear tridentate amines and Cu(I)Br in both LA and the non-polar solvents required for the formed poly(lauryl acrylate) (pLA) resulted in poor control of the polymer molecular weights and high polydispersity. The use of a soluble catalyst formed by complexing copper with 4,4′-di(5-nonyl)-2,2′-bipyridine, improved both molecular weight control and polydispersities. The experimental conditions were further optimized by adding deactivating Cu(II) complex to the initial reaction mixture to compensate qualitatively for differences in the rate of termination relative to other acrylates.     

PREPARATION AND PROPERTIES OF MMA/1-PROPYLMETHACRYLATE-POSS COPOLYMER WITH ATOM TRANSFER RADICAL POLYMERIZATION

The methyl methacrylate(MMA)/1-propylmethacrylate-polyhedral oligomeric silsesquioxane(PM-POSS) copolymers were synthesized via atom transfer radical polymerization with CuBr as catalyst.The unreacted PM-POSS monomer could be removed completely by washing the copolymerization product with n-hexane.The copolymers were characterized with ~1H-NMR,X-ray diffraction,differential scanning calorimetry,thermogravimetric analysis and gel permeation chromatography.With increasing PM-POSS feed ratio,the total conve...     

SYNTHESIS OF POLYPROPYLENE-POLY(METH)ACRYLATE BLOCK COPOLYMERS USING METALLOCENE CATALYZED PROCESSES AND SUBSEQUENT ATOM TRANSFER RADICAL POLYMERIZATION

ABSTRACT

The synthesis of block copolymers containing low molar mass polypropylene and poly(meth)acrylates is reported. Vinyl-terminated polypropylene (M_n SEC=3,100; M_w/M_n=1.45) was used to prepare a macroinitiator for atom transfer radical polymerization (ATRP) via hydrosilation with 1-(2-bromoisobutyryloxy)propyl-tetramethyldisiloxane. Polar segments were then incorporated to polypropylene by chain extension using either methyl methacrylate, or n-butyl acrylate. While blocking efficiency was limited in this system, well-defined PP-b-PMMA (M_n=22,220; M_w/M_n=1.14) was obtained by extraction of unreacted polypropylene with diethyl ether.     

NEW INITIATION SYSTEMS FOR ATOM TRANSFER RADICAL POLYMERIZATION

This review summarizes our achievements in designing new initiation systems for atom transfer radical polymerization (ATRP). First-order kinetics and extension experiments revealed the living nature of these reactions. Tailormade vinyl polymers with functional end groups were characterized by ^1H-NMR and UV-vis spectroscopic analyses. Replacing traditional radical initiators AIBN and BPO, carbon-carbon bond compounds, 1,1,2,2-tetraphenyl-l,2-ethanediol, diethyl 2,3-dicyano-2,3-diphenylsuccinate and diethyl 2,3-dicyano-2,3-di(p-tolyl)succinate, were utilized in reverse ATRP to produce the initiating radical. Sulfur-sulfur bond iniferter, tetraethylthiuram disulfide (TD), in conjunction with CuBr/bpy or NiCI2/PPh3 complex could control the styrene polymerization via redox reaction. Pseudo-halogen transfer reaction was demonstrated to maintain the dormant-active species equilibrium in normal and reverse ATRP with Cu(S2CNEt2), Cu(S2CNEt2)CI and Fe(S2CNEt2)3 as catalysts. The organic halide initiator and reduced transition metal compound that started the living polymerization were produced in situ from the components of TD/FeCI3/PPh3, TD/CuBr2/bpy and Fe(S2CNEt2)3/FeCI3/PPh3 systems. Accurate control of UV irradiation time favored the radical generation process in photo ATRP with the 2,2-dimethoxy-2-phenylacetophenone/Fe(S2CNEt2)3 initiation system.     

富马酸亚铁催化甲基丙烯酸甲酯活性自由基聚合的研究

以畜马酸亚铁为催化剂,以2-溴代异丁酸乙酯为引发剂,在90℃下进行甲基丙烯酸甲酯的原子转移自由基本体聚合及溶液聚合.聚合物的数均相对分子质量随单体转化率的增加而线性增加,与时间呈良好线性关系,本体聚合时分子量分布(PDI)在1.5～1.7之间,溶液聚合时PDI＜1.5.通过聚合物扩链反应和端基分析,表明富马酸亚铁催化原子转移自由基聚合反应具有活性(可控)聚合的特征.     

富马酸亚铁催化甲基丙烯酸甲酯活性自由基聚合的研究

以富马酸亚铁为催化剂,以2-溴代异丁酸乙酯为引发剂,在90℃下进行甲基丙烯酸甲酯的原子转移自由基本体聚合及溶液聚合.聚合物的数均相对分子质量随单体转化率的增加而线性增加,与时间呈良好线性关系,本体聚合时分子量分布 (PDI) 在1.5～1.7之间,溶液聚合时PDI＜1.5.通过聚合物扩链反应和端基分析,表明富马酸亚铁催化原子转移自由基聚合反应具有活性(可控)聚合的特征.     

甲基丙烯酸甲酯的原子转移自由基悬浮聚合

以 1 苯基氯乙烷为引发剂 ,氯化亚铜为催化剂 ,2 ,2 联吡啶为配体 ,外加搅拌 ,氮气保护下进行了甲基丙烯酸甲酯 (MMA)在 80℃下的原子转移悬浮聚合 .结果表明 ,聚合反应符合对单体浓度为一级的动力学关系 .经计算聚合体系的增长自由基浓度为 5 .74× 10 - 8mol L .聚合物分子量随转化率呈线性增加 ,分子量分布较窄 ,Mw Mn 在 1.37～ 1.40之间 .还以AIBN为引发剂 ,在三氯化铁和三苯基膦存在下进行了MMA的反向原子转移本体和悬浮聚合研究 .结果证明本体聚合具有好的可控特征 ,分子量随转化率呈线性增长 ,分子量分布指数在 1.2 7～ 1.31之间 .聚合反应速率较快 ,聚合体系中的增长自由基浓度较高 ,为 1.6 4× 10 - 7mol L .而在此催化体系下的悬浮聚合则完全失去了活性特征     

ATRP技术用于热敏性高聚物在硅胶表面的接枝

在超细硅胶表面引入原子转移自由基聚合(ATRP)的引发基团,通过ATRP技术使N-异丙基丙烯酰胺(NIPAM)在硅胶表面接枝聚合,合成得到了具有温敏性的核-壳复合微粒.通过FTIR,TG,EA,SEM,DSC等分析方法对接枝前后的复合粒子进行了分析与表征,结果证明聚N-异丙基丙烯酰胺(PNIPAM)接在了硅胶表面.TG分析得出PNIPAM在硅胶表面的接枝率达到25.2%;DSC分析表明复合硅胶具有温度敏感性,在34.1℃时发生相转变行为;GPC分析得出从复合硅胶表面"劈下"的聚合物PNIPAM的数均分子量约为8000,分子量分布为1.06.复合微粒表面均匀平坦,显示出活性聚合的优越性.     

原子转移自由基聚合制备聚(丙二醇-g-苯乙烯)

以氯甲基化苯氧基聚丙二醇 (CMPOPPG)为大分子引发剂 ,由CuCl/bpy催化的苯乙烯原子转移自由基聚合反应合成了聚 (丙二醇 g 苯乙烯 ) .CMPOPPG经环氧丙烷 (PO)与缩水甘油苯基醚 (GPE)的开环聚合和氯甲基化反应制得 .接枝聚合反应具有可控性 .用1H NMR和微库仑分析法对接枝共聚物进行了表征 .结果表明 ,支链分子量可控 ,接枝率可达 8.6.     

KINETICS AND MECHANISM OF PHASE TRANSFER CATALYZED FREE RADICAL POLYMERIZATION OF METHYL ACRYLATE

The kinetics of free radical polymerization of methylacrylate (MA) was investigated using benzyltributylammonium chloride (BTBAC) as phase transfer catalyst and potassium peroxydisulfate as initiator at aconstant temperature, 60°C, in an inert atmosphere under unstirred condition. The effect of concentrations of the monomer, initiator and the catalyst on polymerization was discussed and a mechanism of polymerization has been proposed. The order with respect to the monomer, initiator, and phase transfer catalyst was found to be 2, 0.5, and 0.5, respectively.     

THERMOSENSITIVITY OF NARROW-DISPERSED POLY(N-n-PROPYLACRYLAMIDE) PREPARED BY ATOM TRANSFER RADICAL POLYMERIZATION

Controlled polymerization of N-n-propylacrylamide was achieved by atom transfer radical polymerization(ATRP) in a N,N-dimethylformamide-water mixture(50 vol%)at room temperature with methyl 2-chloropropinonate as initiator and CuCl/tris(2-dimethylaminoethyl)amine as the catalytic system in a ratio of 1:1:1.High molecular weight homopolymers(up to 3.7×10~4)with narrow molecular weight distribution(less than 1.2)were obtained.The living character of the polymerization was further demonstrated by self-block...