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．     

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 …

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。     

碳酸钙在St-MMA悬浮聚合中的应用研究

以碳酸钙为分散剂,过氧化二苯甲酰为引发剂,采用悬浮聚合法合成苯乙烯-甲基丙烯酸甲酯共聚物。研究了碳酸钙用量、反应温度、反应时间、引发剂用量、水与单体体积比、苯乙烯与甲基丙烯酸甲酯体积比对悬浮聚合的影响。结果表明,碳酸钙用量为2.0~3.0g,反应温度为75~80℃,反应时间为3h,引发剂用量为0.3115g,水与单体体积比为5:1~7:1,苯乙烯与甲基丙烯酸甲酯体积比为1/8.5~1:1(单体总体积为9.5m L)时,制得的共聚物颗粒大小均匀,粒径在0.31mm~0.60mm,产率在90%以上。     

两种不同取代结构C_(60)-苯乙烯共聚物薄膜微摩擦性能的研究

用自由基聚合法合成星状C6 0 苯乙烯共聚物和用原子转移自由基聚合法 (ATRP)合成单取代C6 0 苯乙烯共聚物 ,利用LB技术考察了它们的成膜性能并制备了多层薄膜 ,运用原子力显微镜 摩擦力显微镜(AFM FFM)初步研究比较这两种不同取代结构C6 0 苯乙烯共聚物薄膜的表面形貌和在极轻载荷下的微摩擦性能 .研究结果显示了星状C6 0 苯乙烯共聚物相对具有较好的润滑性能     

β-蒎烯嵌段、接枝共聚物的合成

分别使用苯乙烯 HCl加成物 (a)和 2 氯乙基乙烯基醚 HCl加成物 (b)作为引发剂 ,TiCl4 Ti(OiPr) 4(3∶1mol mol)为活化剂 ,在nBu4NCl存在下 ,- 40℃、CH2 Cl2 中 ,通过顺序活性阳离子聚合 ,合成了 β 蒎烯与苯乙烯、对甲基苯乙烯的嵌段共聚物 .又用带丙烯酰氧功能基的引发剂c [CH3CH (OCH2 CH2 X )Cl,X =OCOC(CH3)CH2 ]引发 β 蒎烯活性阳离子聚合 ,合成了 β 蒎烯大分子单体 .该大分子单体在AIBN引发下与甲基丙烯酸甲酯进行自由基共聚 ,获得主链为聚甲基丙烯酸甲酯、侧链为聚 β 蒎烯的接枝共聚物     

β-蒎烯嵌段、接枝共聚物的合成

分别使用苯乙烯 HCl加成物 (a)和 2 氯乙基乙烯基醚 HCl加成物 (b)作为引发剂 ,TiCl4 Ti(OiPr) 4(3∶1mol mol)为活化剂 ,在nBu4NCl存在下 ,- 40℃、CH2 Cl2 中 ,通过顺序活性阳离子聚合 ,合成了 β 蒎烯与苯乙烯、对甲基苯乙烯的嵌段共聚物 .又用带丙烯酰氧功能基的引发剂c [CH3CH (OCH2 CH2 X )Cl,X =OCOC(CH3)CH2 ]引发 β 蒎烯活性阳离子聚合 ,合成了 β 蒎烯大分子单体 .该大分子单体在AIBN引发下与甲基丙烯酸甲酯进行自由基共聚 ,获得主链为聚甲基丙烯酸甲酯、侧链为聚 β 蒎烯的接枝共聚物     

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.     

极性单体对苯乙烯—二乙烯苯共聚反应的影响及动力学研究.Ⅰ.

本文对分别加入丙烯腈、醋酸乙烯酯和甲基丙烯酸甲脂的苯乙烯—二乙烯苯共聚反应体系进行了动力学研究,并考察了聚合物的溶胀性能以及所合成的离子交换树脂的交换量和强度。结果表明:在苯乙烯—二乙烯苯共聚反应体系中,加入少量的极性单体,改变了苯乙烯与二乙烯苯的相对聚合速率,从而起到了调节共聚物中化学交联点分布的作用。共聚物网络结构的这一变化使其溶胀性能和强度也相应地发生了一定变化。     

β-蒎烯嵌段、接枝共聚物的合成

分别使用苯乙烯-HCl加成物(a)和2-氯乙基乙烯基醚-HCl加成物(b)作为引发剂,TiCl4/Ti(OiPr)4(3∶1mol/mol)为活化剂,在nBu4NCl存在下,-40℃、CH2Cl2中,通过顺序活性阳离子聚合,合成了β-蒎烯与苯乙烯、对甲基苯乙烯的嵌段共聚物.又用带丙烯酰氧功能基的引发剂c [CH3CH(OCH2CH2X)Cl, X=OCOC(CH3)CH2] 引发β-蒎烯活性阳离子聚合,合成了β-蒎烯大分子单体.该大分子单体在AIBN引发下与甲基丙烯酸甲酯进行自由基共聚,获得主链为聚甲基丙烯酸甲酯、侧链为聚β-蒎烯的接枝共聚物.     

部分水解聚(丙烯酸甲酯-乙酸乙烯酯-甲基丙烯酸甲酯)高吸水性树脂的合成及结构研究

研究了部分水解聚(丙烯酸甲酯-乙酸乙烯酯-甲基丙烯酸甲酯)高吸水性树脂-HP(MA-VAc-MMA)的合成,讨论了聚合,水解工艺条件对该树脂吸水(液)性能的影响,用红外,X-射线衍射和电子衍射等方法测定了共聚物的结构。结果表明,HP(MA-VAc-MMA)树脂的吸水能力为:去离子水837ml/g、自来水440ml/g、0.9%NaCl溶液ml/g、合成血119ml/g、合成尿73ml/g;该树脂具有结晶结构,与PVC树脂共混可制备吸水膨胀性材料。     

The characterization of latex particles prepared by pulsed electron beam induced emulsion polymerization

The emulsion polymerization of styrene (St) and methyl methacrylate (MMA) induced by 10 MeV pulsed electron beams (PEB) was investigated. The monomer conversion of MMA and St was found to be very low so that the final prepared poly(methyl methacrylate) (P(MMA)) and polystyrene (PS) latex particles exhibit porous structures, as verified by TEM and SEM observations. The results of dynamic light scattering (DLS) and gel permeation chromatography (GPC) showed that both the particle size and the molecular weight of PS and PMMA latexes decrease with the increase of the absorbed dose. However, the molecular weights and the particle sizes of the PS and PMMA latexes change differently with the irradiation time. This work indicated that emulsion polymerization induced by high energy electron beam has an advantage over that induced by γ-ray or chemical initiators in the preparation of latex with a low molecular weight and porous structure.     

一种大分子引发剂的引发作用研究

将溶液聚合合成的α-甲基苯乙烯(AMS)和甲基丙烯酸缩水甘油酯(GMA)的低相对分子质量共聚物(计为PAG)作为大分子引发剂,分别研究了PAG引发单体甲基丙烯酸甲酯(MMA)和苯乙烯(St)的本体聚合反应,采用GPC和FTIR等手段对聚合产物进行了表征.研究结果表明,在加热到一定温度时,PAG具有引发作用,可以引发MMA和St进行本体聚合反应;聚合产物具有再引发功能,且其分子量与聚合物产率和聚合反应时间之间均有较好的线性关系.     

A Facile Synthesis of Cleavable Block Copolymers via Tandem Polymerizations of NMRP and ATRP

A functionalized compound, 4‐(2‐bromoisobutyryl)‐2,2,6,6‐tetra‐methylpiperidine‐1‐oxyl (Br‐TEMPO), was synthesized and used to synthesize block copolymers through tandem nitroxide‐mediated radical polymerization (NMRP) and atom transfer radical polymerization (ATRP). First, Br‐TEMPO was used to mediate the polymerization of styrene. The kinetics of polymerization proved a typical “living” nature of the reaction and the effectiveness in the mediation of polymerization of Br‐TEMPO. Then the PS‐Br macroinitiator was used to initiate atom transfer radical polymerization (ATRP). A series of acrylates were initiated by PS‐Br macroinitiators in typical ATRP processes at various conditions. The controlled polymerization of ATRP was also confirmed by molecular weight and kinetic analysis. Several cleavable block copolymers of PS‐b‐P(t‐BA), PS‐b‐P(n‐BA), and PS‐b‐PMA, with different molecular weights, were synthesized via this strategy. Relatively low polydispersities (<1.5) were observed and the molecular weights were in agreement with the theoretical ones. Hydrolysis of PS‐b‐P(t‐BA) was carried out, giving amphiphilic block copolymer PS‐b‐PAA without the cleavage of C‐ON bond or ester bond. All the block copolymers have two T_gs as demonstrated by DSC. A typical cleavable block copolymer of PS‐b‐PMA was cleaved by adding phenylhydrazine at 120°C to produce homopolymers in situ.     

苯乙烯—环氧乙烷嵌段共聚物的阴离子聚合与表征

用二苯甲烷钾为引发剂,阴离子聚合法合成了苯乙烯（Ｓｔ）－环氧乙烷（ＥＯ）嵌段共聚物,并用ＦＴＩＲ,＾１Ｈ－ＮＭＲ,ＳＥＣ,ＷＡＸＤ和动态粘弹谱对共聚物进行了表征。结果表明所得聚合物为分子量可控,窄分布的两嵌段共聚物。     

Poly(ethylene-co-propylene)-g-polystyrene through macromer polymerization: Preparation,morphology, and structure–properties relationships

Graft copolymers with ethylene-propylene (EPR) backbone and polystyrene (PS) grafts, EPR-g-PS, were prepared by terpolymerization of a PS macromer with ethylene and propylene using a vanadium catalyst, with graft efficiency of up to 80% and PS content in the copolymer 5–45%. Such polymerization parameters as molecular weight and dosage of the macromer, catalyst concentration, and reaction temperature which affect the mobility and hence polymerizability of the macromer may have a marked influence on the polymerization and the structure of the products. The molecular architecture of the copolymers was characterized by osmometry, UV, NMR, and GPC methods. TEM and torsional pendulum studies revealed that EPR-g-PS possessed a phase separation morphology with PS domains evenly dispersed in the EPR matrix. The PS content and average number of grafts strongly influence the tensile properties of the copolymers. EPR-g-PS graft copolymers prepared by macromer copolymerization exhibit the mechanical properties of a typical thermoplastic elastomer having two or more branches of a certain length.     

An efficient synthetic route to well‐defined theta‐shaped copolymers

A series of well‐defined θ‐shaped copolymers composed of polystyrene (PS) and poly(ε‐caprolactone) (PCL) with controlled molecular weight and narrow molecular weight distribution have been successfully synthesized without any purification procedure by the combination of atom transfer radical polymerization (ATRP), ring‐opening polymerization (ROP), and the “click” chemistry. The synthetic process involves two steps: (1) synthesis of AB₂ miktoarm star copolymers, which contain one PCL chain terminated with two acetylene groups and two PS chains with two azido groups at their one end, (α,α′‐diacetylene‐PCL) (ω‐azido‐PS)₂, by ROP, ATRP, and the terminal group transformation; (2) intramolecular cyclization of AB₂ miktoarm star copolymers to produce well‐defined pure θ‐shaped copolymers using “click” chemistry under high dilution. The ¹H NMR, FTIR, and gel permeation chromatography techniques were applied to characterize the chemical structures of the resultant intermediates and the target polymers. Their thermal behavior was investigated by DSC. The mobility decrease of PCL chain across PS ring in the theta‐shaped copolymers restricts the crystallization ability of PCL segment. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2620–2630, 2009     

Photo- and radiation-induced degradation of poly(styrene-co-methyl methacrylate)

The photo- and radiation-induced degradation of poly(styrene-co-methyl methacrylate) (poly(St-co-MMA)) has been investigated by both electron spin resonance (ESR) and viscosity measurements. On ultraviolet irradiation of poly(St-co-MMA) film at 30°C in vacuum, the scission type radical from poly(methyl methacrylate) is produced in the initial stages of the photo-irradiation. The polystyryl radical from polystyrene gradually increases with irradiation time. The resulting ESR spectrum is composed of those of both radicals. The ratio of the radicals produced in poly(St-co-MMA) by photo-irradiation was estimated by comparison with simulated ESR spectra. The viscosity average molecular weight, $\text{Mv}$ of photo-irradiated poly(St-co-MMA) decreases at short irradiation times and gradually increases at longer irradiation times. This phenomenon reflects the fact that the photo-degradation of the copolymer begins from the MMA component in poly(St-co-MMA). The γ-ray-induced degradation of poly(St-co-MMA) has also been examined by the same methods as those used in the photo-degradation and confirms that the degradation begins from the MMA component in the copolymer. The protective effect of polystyrene was also found for the radiation-induced degradation of the polymethyl methacrylate units in poly(St-co-MMA).     

用双官能团引发剂进行的原子转移自由基嵌段和无规共聚

原子转移自由基聚合［１］,可同时适用于非极性单体和极性单体,如苯乙烯、二烯烃类和（甲基）丙烯酸酯、丙烯腈类单体［１～３］,这是传统的活性聚合如阴离子聚合和基团转移聚合所不及的;可以用于制备包括无规、嵌段、星形与高支化物在内的诸多结构清晰的高分子化合物...     

四臂星型聚苯乙烯-聚4-乙烯基吡啶嵌段共聚物纤维状胶束及负载金纳米粒子的研究

通过两步原子转移自由基聚合,制备了4种不同嵌段长度的四臂星型嵌段共聚物苯乙烯-聚4-乙烯基吡啶嵌段共聚物(PS-b-P4VP)4.在选择性溶剂甲苯中,随着嵌段长度的变化,自组装胶束的形态从球型到短棒状和纤维状的转变,其中(PS25-b-P4VP90)4自组装形成的以P4VP为核,以PS为花瓣型壳的纤维状胶束.以这种纤维状胶束作为模板,制备了金纳米粒子均匀分布的一维纳米材料     

H_2O/TiCl_4/Py体系引发苯乙烯正离子聚合

研究了在少量吡啶(Py)存在下由水(H2O)四氯化钛(TiCl4)体系引发苯乙烯于二氯甲烷正己烷中进行碳正离子聚合,分别考察[Py]、[H2O]和[TiCl4]对聚合速率、产物分子量与分子量分布的影响.实验结果表明,少量亲核试剂吡啶(Py)对聚合反应起着重要作用,可有效地降低聚合速率和使分子量分布变窄;随着[H2O]和[Py]降低或[TiCl4]增加,聚合产物的分子量增加,而分子量分布指数(Mw Mn)基本维持在1.8左右;随着[Py]增加,聚合速率降低;随着[H2O]和[TiCl4]增加,聚合速率提高.聚合速率对单体浓度呈一级动力学关系,对Py、H2O和TiCl4的反应级数分别为-0.72、0.72和1.86.聚合速率对TiCl4浓度呈接近二级动力学关系,这可能与体系中TiCl4主要以二聚体形式存在有关.聚合转化率和产物分子量均随着反应时间延长而逐渐增大,PS的数均分子量与转化率呈线性增加关系.