N-水杨醛缩二乙烯三胺作为配体催化原子转移自由基聚合

采用水杨醛和二乙烯三胺反应合成用于原子转移自由基聚合的新型配体——N-水杨醛缩二乙烯三胺,通过元素分析和核磁共振表征N-水杨醛缩二乙烯三胺,以乙-溴代丙酸乙酯（EBP）为引发剂,用N-水杨醛缩二乙烯三胺催化合成聚甲基丙烯酸甲酯（PMMA）,并采用凝胶渗透色谱（GPC）测其相对分子质量及其分布,考察聚合体系的动力学.结果表明：甲基丙烯酸甲酯（MMA）/EBP/溴化亚铜/N-水杨醛缩二乙烯三胺体系和MMA/EBP/溴化亚铜/N-水杨醛缩二乙烯三胺/N,N-二甲基甲酰胺（DMF）体系的原子转移自由基聚合符合一级动力学规律,且具有＂活性＂和可控性,相对分子质量分布较窄（前者为1.46,后者为1.34）,加入溶剂后,催化活性和自由基浓度均有所下降.     

Reverse atom transfer radical polymerization of acrylonitrile

FeCl₃ coordinated by succinic acid was used as the catalyst for the first time in azobisisobutyronitrile‐initiated reverse atom transfer radical polymerization of acrylonitrile (AN). N,N‐dimethylformamide (DMF) was used as a solvent to improve the solubility of the ligand. A FeCl₃ to succinic acid ratio of 0.5 not only gives the best control of molecular weight and its distribution but also provides rather rapid reaction rate. Effects of different solvents on polymerization of AN were also investigated. The rate of the polymerization in DMF is faster than that in propylene carbonate and toluene. The molecular weight of polyacrylonitrile agrees reasonably well with the theoretical molecular weight in DMF. The rate of polymerization increases with increasing the polymerization temperature, and the apparent activation energy was calculated to be 64.8 kJ mol^?1. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 32–36, 2006     

Reverse atom transfer radical polymerization of acrylonitrile under microwave irradiation

Reverse atom transfer radical polymerization was first used to successfully synthesize polyacrylonitrile under microwave irradiation. FeCl₃, coordinated by isophthalic acid, was used as the catalyst, and 2,2′‐azobisisoheptonitrilewas used as the initiator. N,N‐Dimethylformamide was used as the solvent to improve the solubility of the ligand. Under the same experimental conditions, the apparent rate constant under microwave irradiation was higher than that under conventional heating. The polymerization not only showed the best control of the molecular weight and its distribution but also provided a rather rapid reaction rate with the [acrylonitrile]/[2,2′‐azobisisoheptonitrile]/[FeCl₃]/[isophthalic acid] ratio of 300 : 1 : 1 : 2. The polymers obtained were used as macroinitiators to initiate the chain extension and successfully synthesize acrylonitrile polymers with a molecular weight higher than 50,000 and a narrow polydispersity as low as 1.30. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Reverse atom transfer radical polymerization of methyl methacrylate in different solvents

The reverse atom transfer radical polymerization of methyl methacrylate was investigated in different solvents: xylene, N,N‐dimethylformamide, and pyridine. The polymerizations were uncontrolled, using 2,2′‐bipyridine as a ligand in xylene and pyridine because the catalyst (CuBr₂/2,2′‐bipyridine complex) had poor solubility in the xylene system. In the pyridine system, the solubility of the catalyst increased, but the solvent could complex with CuBr₂, which influenced the control of the polymerization. In the N,N‐dimethylformamide system, the catalyst could be dissolved in the solvent completely, but the ? N(CH₃)₂ group in N,N‐dimethylformamide could also complex with CuBr₂, so the polymerization could not be well controlled. The ligand of 4,4′‐di(5‐nonyl)‐2,2′‐bipyridine was also investigated in xylene; the introduction of the ? CH(C₄H₉)₂ group enabled the CuBr₂/4,4′‐di(5‐nonyl)‐2,2′‐bipyridine complex to easily dissolve in xylene, and the polymerizations were well controlled. The number‐average molecular weight increased linearly with the monomer conversion from 4280 to 14,700. During the whole polymerization, the polydispersities were quite low (1.07–1.10). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Atom transfer radical polymerization of acrylonitrile

Iron(II) chloride coordinated by succinic acid was first used as the catalyst in 2‐chloropropionitrile‐initiated atom transfer radical polymerization (ATRP) of acrylonitrile. N,N‐dimethylformamide was used as a solvent to improve the solubility of the ligand. An iron(II) chloride to succinic acid ratio of 0.5 not only gives the best control of molecular weight and its distribution but also provides rather rapid reaction rate. Effects of solvent on polymerization of acrylonitrile were also investigated. The induction period is shorter in N,N‐dimethylformamide than in propylene carbonate and toluene and the rate of the polymerization in N,N‐dimethylformamide is fastest. The molecular weight of polyacrylonitrile agrees reasonably well with the theoretical molecular weight of N,N‐dimethylformamide. The rate of polymerization increases and the induction period becomes shorter with increasing polymerization temperature, and the apparent activation energy was calculated to be 56.5 kJ mol^?1. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1050–1054, 2006     

m－DVB和p－DVB原子转移自由基聚合动力学

以氯端基聚苯乙烯为大分子引发剂,氯化亚铜／２,２’－联二吡喧为催化剂,邻二甲苯为溶剂,用气相色谱分别研究了对二乙烯基苯（ｐ－ＤＶＢ）和间二乙烯在苯（ｍ－ＤＶＢ）在１００￣１３０℃的原子转移自由基聚合动力学。结果表明,聚合符合表观一级反应动力学。ｐ－ＤＶＢ在１００,１１０,１２０、１３０℃的聚合速率常数分别为０．０７２,０．１２８,０．３７９,０．５４６ｈ＾－１,ｍ－ＤＶＢ在上述不同温度的聚合速率常     

原子转移自由基乳液聚合研究进展

原子转移自由基聚合(ATRP)作为一种可控/活性聚合方法,可对聚合物结构进行精确控制;乳液聚合以水作为分散介质,具有经济、环保等特点。因此,乳液ATRP结合了两者的优点,具有工业化生产的潜力。首先分析了影响乳液ATRP的各种因素,然后综述了正向ATRP、RATRP(反向ATRP)、SR&NI ATRP(正向/反向同时进行的ATRP)和AGET ATRP(电子转移活化剂ATRP)等机制及研究进展,最后对乳液ATRP的发展方向进行了展望。     

原子转移自由基聚合最新研究进展

概述了原子转移自由基聚合（ATRP）在引发体系、反应温度、反应介质、实施方法等方面的进展；介绍了3种不同催化剂脱除技术；结合最新的研究成果，着重论述了ATRP在进行聚合物分子设计，制备窄分子量分布聚合物、无规、梯度和交替共聚物，嵌段共聚物，末端官能团聚合物，接枝和梳状聚合物，星型及高支化聚合物等方面的应用。     

Kinetic study of atom transfer radical polymerization of methyl methacrylate in ionic liquids

The kinetics of methyl methacrylate (MMA) homopolymerization performed by atom transfer radical polymerization (ATRP) is investigated in detail using ethyl‐2‐bromopropionate (EPN‐Br) as initiator, CuBr as catalyst, and pentamethyldiethylenetriamine (PMDETA) as ligand in ionic liquids (ILs) and acetonitrile. ILs in this research covered two different substitutional imidazolium cations and anions including halogen and halogen‐free ones. The typical cations include 1‐butyl‐3‐methylimidazolium, 1‐ethyl‐3‐methylimidazolium and the typical anions include bromide, tetrafluoroborate. The effects of solvents, temperature, and reaction ingredients ratios on the polymerization kinetics are all investigated in this article and the apparent energy of activation (ΔE) calculated for the ATRP of MMA in 1‐butyl‐3‐methyl‐imidazolium tetrafluoroborate is 6.95 KJ/mol. The number‐average molecular weights (M_n) increase linearly with conversion but are much higher than the theoretical values. It is probably due to the low concentration of deactivator at the early stage of polymerization and the lower bond energy of C‐Br in PMMA‐Br than that in EPN‐Br. Moreover, the catalyst is easily separated from the polymer and the regenerated catalyst is reused for more than three times. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Atom transfer radical polymerization and copolymerization of vinyl acetate catalyzed by copper halide/terpyridine

Copper‐mediated atom transfer radical polymerization (ATRP) is versatile for living polymerizations of a wide range of monomers, but ATRP of vinyl acetate (VAc) remains challenging due to the low homolytic cleavage activity of the carbon‐halide bond of the dormant poly(vinyl acetate) (PVAc) chains and the high reactivity of growing PVAc radicals. Therefore, all the reported highly active copper‐based catalysts are inactive in ATRP of VAc. Herein, we report the first copper‐catalyst mediated ATRP of VAc using CuBr/2,2′:6′,2″‐terpyridine (tPy) or CuCl/tPy as catalysts. The polymerization was a first order reaction with respect to the monomer concentration. The molecular weights of the resulting PVAc linearly increased with the VAc conversion. The living character was further proven by self‐chain extension of PVAc. Using polystyrene (PS) as a macroinitiator, a well‐defined diblock copolymer PS‐b‐PVAc was prepared. Hydrolysis of the PS‐b‐PVAc produced a PS‐b‐poly(vinyl alcohol) amphiphilic diblock copolymer. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

反向原子转移自由基聚合研究进展

原子转移自由基聚合是一种新兴的活性/可控聚合方法,而反向ATRP又是在传统ATRP方法基础上衍生出的一种摒弃ATRP方法中一些缺点的新生活性聚合方法。文中介绍了反向ATRP的建立原理,从单体、引发剂、催化体系等方面综述了反向ATRP的研究进展。     

采用原子转移自由基聚合技术制备聚丙烯酸钠的研究

采用原子转移自由基聚合(ATRP)技术在水溶液和N,N-二甲基甲酰胺的混合溶液中一步合成了聚丙烯酸钠。考察了反应温度、溶液pH、维生素C(Vc)对聚合反应的影响。结果表明,采取ATRP技术可以制备得到数均分子量为6.8 kDa以及分散度2.4的聚丙烯酸钠。     

High‐molecular‐weight polyacrylonitrile by atom transfer radical polymerization

A single‐pot atom transfer radical polymerization was used for the first time to successfully synthesize polyacrylonitrile with a molecular weight higher than 80,000 and a narrow polydispersity as low as 1.18. This was achieved with CuBr/isophthalic acid as the catalyst, 2‐bromopropionitrile as the initiator, and N,N‐dimethylformamide as the solvent. The effects of the solvent on the polymerization of acrylonitrile were also investigated. The induction period was shorter in N,N‐dimethylformamide than in propylene carbonate and toluene, and the rate of the polymerization in N,N‐dimethylformamide was fastest. The molecular weight of polyacrylonitrile agreed reasonably well with the theoretical molecular weight in N,N‐dimethylformamide. When chlorine was used in either the initiator or the catalyst, the rate of polymerization showed a trend of decreasing, and the molecular weight deviated from the theoretical predication significantly. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3372–3376, 2006     

原子转移自由基聚合合成支化聚丙烯腈

以二乙烯苯为支化单体,α-溴代异丁酸叔丁酯为引发剂,CuBr和2,2'-联吡啶为催化体系,利用本体和溶液原子转移自由基聚合合成了支化聚丙烯腈.采用核磁共振谱仪、凝胶渗透色谱仪和多角度激光光散射仪等测试了聚合物结构、相对分子质量及其分布.用无水乙酸钠对支化聚丙烯腈进行末端改性,得到了在硫氰酸钠水溶液中性能稳定、可长期保存的支化聚丙烯腈,而改性对聚合物的耐热性能没有影响.     

Evaluation of the confinement effect of nanoclay on the kinetics of styrene atom transfer radical polymerization

The grafting through method was employed to study the effect of nanoclay confinement on the atom transfer radical polymerization (ATRP) of styrene. An ammonium salt containing a double bond on its structure was used as a clay modifier. Employing ATRP to polymerize styrene in the presence of modified montmorillonite resulted in a finely well‐defined polystyrene nanocomposite. The gas chromatography (GC) results showed the linear increase of ln(M₀/M) versus time, which indicated the controlled behavior of the polymerization. Another confirmation of the living nature of the polymerization was the linear increase of molecular weight against monomer conversion concluded from the gel permeation chromatography (GPC) data. Nanoclay exerted acceleration on the polymerization of free polystyrene chains. The polydispersity indexes of polymer chains increased by the addition of nanoclay. In the case of clay‐attached polystyrene chains, number and weight‐average molecular weights were lower than that of freely dispersed polystyrene chains. The polydispersity index of the clay‐attached chains was higher in respect to the freely dispersed polystyrene chains. The living nature of polymer chains was more elucidated by Fourier transform infrared spectroscopy (FTIR). Exfoliation of the clay layers in the polymer matrix of polystyrene nanocomposite containing the lowest amount of nanoclay has proven by Transmission Electron Microscopy (TEM). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

原子转移自由基法合成乙丙橡胶接枝物中的热聚合研究

采用原子转移自由基聚合法(ATRP)合成了三元乙丙橡胶与苯乙烯的接枝共聚物(EPDM-g-St),动力学研究表明聚合过程为“活性”聚合。在接枝聚合过程中发现了明显的苯乙烯热聚合现象。对接枝聚合中得到的均聚苯乙烯进行表征的结果表明,苯乙烯在ATRP接枝体系中的热聚合过程在一定程度上受到ATRP机理的控制;升高温度和延长反应时间使得热聚合更为显著。     

Synthesis of graft copolymers from a linear polyolefin through a combination of coordination polymerization and atom transfer radical polymerization

This article reports on a facile route for the preparation of methyl acrylate and methyl methacrylate graft copolymers via a combination of catalytic olefin copolymerization and atom transfer radical polymerization (ATRP). The chemistry first involved a transforming process from ethylene/allylbenzene copolymers to a polyolefin multifunctional macroinitiator with pendant sulfonyl chloride groups. The key to the success of the graft copolymerization was ascribed to a fast exchange rate between the dormant species and active radical species by optimization of the various experimental parameters. Polyolefin‐g‐poly(methyl methacrylate) and polyolefin‐g‐poly(methyl acrylate) graft copolymers with controlled architecture and various graft lengths were, thus, successfully prepared under dilute ATRP conditions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Uniform star‐polystyrene nanoparticles prepared by emulsion atom transfer radical polymerization

Pentaerythritol (PT) was converted into four‐arm initiator pentaerythritol tetrakis(2‐chloropropionyl) (PT‐Cl) via reaction with 2‐chloropropionyl chloride. Uniform (monodisperse) star‐polystyrene nanoparticles were prepared by emulsion atom transfer radical polymerization of styrene, using PT‐Cl/CuCl/bpy (bpy is 2,2′‐dipyridyl) as the initiating system. The structures of PT‐Cl and polymer were characterized by Fourier transform infrared spectroscopy and nuclear magnetic resonance. The morphology, size and size distribution of the star‐polystyrene nanoparticles were characterized by transmission electron microscopy, atomic force microscopy and photon correlation spectroscopy. It was found that the average diameters of star‐polystyrene nanoparticles were smaller than 100 nm (30–90 nm) and monodisperse; moreover, the particle size could be controlled by the monomer/initiator ratio and the surfactant concentration. The average hydrodynamic diameter (D_h) of the nanoparticles increased gradually on increasing the ratio of styrene to PT‐Cl and decreased on enhancing the surfactant concentration or increasing the catalyst concentration. Copyright © 2011 Society of Chemical Industry     

A novel ligand for atom transfer radical polymerization

A ligand is a crucial element for atom transfer radical polymerization (ATRP). A new nitrogen-containing compound, 1,1’-(2,2’-(ethane-1,2-diylbis(butyl azanediyl)) -bis(ethane-2,1-diyl)) dipyrrolidin-2-one (DBBD), was synthesized and utilized as the ligand of copper halide for ATRP of methyl methacrylate (MMA) and methyl acrylate (MA). It was found that the CuBr/DBBD and Ethyl 2-bromoisobutyrate (EBIB) system could mediate the polymerization of MMA and the reaction was first-order kinetics, although the control of molecular weights was not perfect. When CuCl was used to replace CuBr, the molecular weights of obtained polymers were well controlled, which indicated the halide exchange could improve the controllability. In the polymerization of MA using Methyl 2-bromopropronate (MBP) or EBIB as initiator and CuCl/DBBD as catalyst, good control of the polymerization could be achieved and the molecular weights were very close to the predicted value.     

Preparation of hyperbranched polymers by atom transfer radical polymerization

A cheap acrylic AB* monomer, 2‐(2‐chloroacetyloxy)‐isopropyl acrylate (CAIPA), was prepared from 2‐hydroxyisopropyl acrylate with chloroacetyl chloride in the presence of triethylamine. The self‐condensing vinyl polymerization by atom transfer radical polymerization (ATRP), a “living”/controlled radical polymerization, has yielded hyperbranched polymers. All the polymerization products were characterized by proton nuclear magnetic resonance spectroscopy (¹H NMR). CAIPA exhibited distinctive polymerization behavior that is similar to a classical step‐growth polymerization in the relationship of molecular weight to polymerization time, especially during the initial stage of the polymerization. However, a significant amount of monomer remained present throughout the polymerization, which is consistent with typical chain polymerization. Also, if a much longer polymerization time was used, the polymer became gel. As a result of the unequal reactivity of group A* and B*, the polymerization is different from an ideal self‐condensing vinyl polymerization: the branch structures of polymers prepared depend dramatically on the ratio of 2,2'‐bipyridyl to CAIPA. Hyperbranched polymers exhibit improved solubility in organic solvent, however, they have lower thermal stability than their linear analogs. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2114–2123, 2002