A FACILE APPROAC0H FOR THE SURFACE MODIFICATION OF POLY(VINYLIDENE FLUORIDE)MEMBRANE VIA SURFACE-INITIATED ATOM TRANSFER RADICAL POLYMERIZATION

A novel approach for the surface modification of poly(vinylidene fluoride)(PVDF)membrane was successfully realized through alkaline treatment,UV-induced bromine addition,and followed by surface-initiated atom transfer radical polymerization(ATRP)of methyl methacrylate(MMA).Chemical changes on the PVDF membrane before and after modification were analyzed with attenuated total reflectance Fourier transform infrared spectroscopy(AIR/Fr-IR)and X-ray photoelectron spectroscopy(XPS).Primary kinetic study revealed that the chain growth of poly(methyl methacrylate)(PMMA)from the PVDF surface is consistent with a"controlled"process.     

HYDROPHILIC MODIFICATION OF PPESK POROUS MEMBRANES VIA AQUEOUS SURFACE-INITIATED ATOM TRANSFER RADICAL POLYMERIZATION

Hydrophilic surface modification of poly(phthalazinone ether sulfone ketone)(PPESK) porous membranes was achieved via surface-initiated atom transfer radical polymerization(ATRP) in aqueous medium.Prior to ATRP.chloromethyl groups were introduced onto PPESK main chains by chloromethylation.Chloromethvlated PPESK(CMPPESK) was fabricated into porous membrane through phase inversion technique.Hydrophilic poly(poly(ethylene glycol) methyl ether methacrylate)(P(PEGMA)) brushes were grafted from CMPPESK membra...     

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.     

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...     

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．     

淬火温度对聚偏氟乙烯形态结构的影响

用透射电子显微镜（ＴＥＭ）和傅里叶交换红外光谱（ＦＴＩＲ）等方法研究了结晶温度对聚偏氟乙烯（ＰＶＦ２）晶相结构的影响．结果表明，从ＰＶＦ２熔体高速淬火到较低温度等温结晶可直接生成β相结晶，临界淬火温度为３０℃．淬火温度在４０—７０℃时，α和β相共存．当淬火温度较高时（８０—１５０℃），生成α相结晶．在淬火温度高于１６５℃时，则得到ＰＶＦ２的γ相结晶．在临界温度以下淬火的ＰＶＦ２薄膜含有β相微晶，而高于临界淬火温度时则生成α相或γ相的片晶或球晶结构．     

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.     

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     

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…     

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 .     

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[     

RHEOLOGICAL PROPERTIES OF POLY(VINYLIDENE FLUORIDE) IN MOLTEN STATE

The theological behavior of poly(vinylidene fluoride)(PVDF)samples of different molecular weights was investigated by means of high pressure capillary rheometer and rotational rheometer.Information on the rheological properties of such materials above melt temperatures is of interest as this can lead to an improved understanding of polymer behavior in processing and fabrication technologies.Shift factors derived from time-temperature superposition showed good fit to the Arrhenius equation with a flow act...     

A NOVEL PHOTO-INITIATING SYSTEM FOR ATOM TRANSFER RADICAL POLYMERIZATION OF STYRENE

A novel photo-induced initiating system, 2, 2 - dimethoxy-2-phenylacetophenone (DMPA)/ferric tri(N,N-diethyl-dithiocarbamate) [Fe(DC)_3], was developed and used for the atom transfer radical polymerization (ATRP) of styrene intoluene. The polymerization proceeds with DMPA as photo-initiator, Fc(DC)_3 as catalyst and DC as a reversible transfergroup, while the halogen and ligands are free. Well-defined PSt was prepared and the polymerization mechanism revealed byend group analysis belongs to a reverse ATRP. Block copolymer was prepared by using thus obtained PSt as macroinitiatorand Fe(DC)_2 as catalyst under UV light irradiation via a conventional ATRP process.     

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.     

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.     

NARROW-DISPERSED CROSSLINKED CORE-SHELL POLYMER MICROSPHERES PREPARED BY SURFACE-INITIATED ATOM TRANSFER RADICAL POLYMERIZATION＊

Grafting of polystyrene with narrowly dispersed polymer microspheres through surface-initiated atom transfer radical polymerization (ATRP) was investigated. Polydivinylbenzene (PDVB) microspheres were prepared by dispersion polymerization with poly(N-vinyl pyrrolidone) (PVP) as stabilizer. The surfaces of PDVB microspheres were chloromethylated by chloromethyl methyl ether in the presence of zinc chloride as catalyst to form chloromethylbenzene initiating core sites for subsequent ATRP grafting of styrene using CuCl/bpy as catalytic system. Polystyrene was found to be grafted not only from the particle surfaces but also from within a thin shell layer, resulting in the formation of particles size increased from 2.38-2.58μm, which can further grow to 2.93μm during secondary grafting polymerization of styrene. This demonstrates that grafting polymerization proceeds through a typical ATRP procedure with living nature. All of the prepared microspheres have narrow particle size distribution with coefficient of variation around 10%.     

异丙醇铝改进的原子转移自由基聚合催化体系

以α 溴代异丁酸乙酯［２ （ＥｉＢ） Ｂｒ］ 为引发剂,溴化亚铜（ＣｕＢｒ）／ 联二吡啶（ｂｐｙ）／ 异丙醇铝［Ａｌ（ＯｉＰｒ）３］ 为复合催化剂,在环己酮溶液中进行了甲基丙烯酸正丁酯（ＢＭＡ） 的原子转移自由基聚合（ＡＴＲＰ） ．研究了异丙醇铝对聚合速率及产物分子量分布的影响．异丙醇铝可与引发剂和聚合物中的羰基配位,使相邻的Ｃ—Ｂｒ 键活化,ＡＴＲＰ 反应可以在较低温度下进行．适量溴化铜的加入,可调节ＡＴＲＰ 活性,可得到分子量可控且分子量分布窄的ＰＢＭＡ（ ＭＷＤ＝ １－３ ～１－５） ．     

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...     

单电子转移活性自由基聚合制备支化聚丙烯酸甲酯的研究

以丙烯酸2-(2-溴异丁酰氧基)乙酯(BIEA)为引发剂单体(inimer),丙烯酸甲酯(MA)为单体,Cu0/CuBr2和N,N,N',N″,N″-五甲基二亚乙基三胺(PMDETA)为催化体系,二甲亚砜(DMSO)为溶剂,在常温(25℃)下通过单电子转移活性自由基聚合(SET-LRP)合成支化聚丙烯酸甲酯.聚合反应过程中,采用气相色谱(GC)、核磁共振(1H-NMR)和三检测体积排除色谱(TD-SEC)等测试手段跟踪分析和表征支化聚合物的结构.研究结果表明,采用SET-LRP方法,铜粉作为催化剂,常温下聚合反应就能快速进行,130 min之内MA的转化率已达99%以上,制备出高分子量支化聚合物.随着反应的不断进行,聚合物支化程度不断提高,相比较同分子量下的线型聚合物其黏度不断下降,Mark-Houwink特征常数α最小可达0.290.此外,低分子量聚合物组分随着反应不断减少,在高单体转化率下,聚合体系中以高支化度的聚丙烯酸甲酯为主.