活性自由基聚合反应与多种结构聚合物的制备

介绍了原民移自由基聚合反应这一新型的活性自由基聚合方式,并综述了利用这种聚合方法制备的多种结构的聚合物,包括嵌段共取物,交替共聚物,接枝共聚物,星形聚合物,超支化聚合物,梳形聚合物等。     

Poly(methylphenylphosphazene)–Graft–Poly(methyl Methacrylate) Copolymers Via Atom Transfer Radical Polymerization

Atom transfer radical polymerization (ATRP) was used to graft poly(methyl methacrylate), PMMA, onto poly(methylphenylphosphazene), [(Me)(Ph)PN] _n , PMPP. A two-step process was used to convert a portion of the methyl substituents on [(Me)(Ph)PN] _n to –CH₂C(CH₃)₂OH groups and then to bromoalkyl groups, –CH₂C(CH₃)₂OC(=O)C(CH₃)₂Br, the latter of which served as initiation sites for ATRP of methyl methacrylate (MMA) in the presence of CuCl/bipyridine. Variations in the length of the grafted chains were investigated and the graft copolymers were compared to the parent polymer and blends of similar composition. The new bromoalkyl derivatives of [(Me)(Ph)PN] _n and the PMPP–graft–PMMA copolymers were characterized by elemental analysis, ¹H and ³¹P NMR spectroscopy, size exclusion chromatography (SEC), and differential scanning calorimetry (DSC). We dedicate this paper to Professor Harry R. Allcock for consistently maintaining the highest standards in his creative, pioneering work in inorganic rings and polymers.     

甲基丙烯酸丁酯的ATRP乳液聚合研究

探讨了铜催化体系催化甲基丙烯酸丁酯 (BMA)的 ATRP乳液聚合规律 ,研究了乳化剂、催化剂、引发剂及反应温度对聚合反应可控性、动力学及乳胶粒性质的影响。结果表明 BMA的 ATRP乳液聚合具有较典型的活性聚合特征 ,并且聚合反应的可控性和乳胶粒的稳定性受上述因素的影响较大 ,得到了聚合反应速率方程和动力学参数。     

反向ATRP乳液聚合法合成聚甲基丙烯酸丁酯的性能研究

采用 Cu 催化剂和偶氮引发剂进行了甲基丙烯酸丁酯的反向原子转移自由基乳液聚合 ,研究了乳化剂、催化剂、反应时间对乳液稳定性、乳胶粒大小和形态以及聚合反应可控性的影响。结果表明原子转移自由基乳液聚合和常规乳液聚合存在着很大的差异 ,特别在成核机理和动力学方面。     

Phase Transfer Catalyst-Induced Free Radical Polymerization of Acrylonitrile Using Water Soluble Initiator – A Kinetic Study

In this paper, we report the kinetics and mechanism of phase transfer catalyzed radical polymerization of acrylonitrile (AN) using potassium peroxydisulphate as water-soluble initiator. The polymerization was executed unstirred at 60°C under nitrogen atmosphere. The roles of concentration of monomer, initiator, catalyst, temperature and effect of solvent polarity were evaluated. Based on the results obtained, a viable kinetic scheme and mechanism have been proposed.     

Free Radical Polymerization of Acrylonitrile Using Potassium Peroxy Disulphate Initiator and a Phase Transfer Catalyst

Free radical polymerization of acrylonitrile with the di-site phase transfer catalyst 1,4-bis(tetramethylhexyl)ethylenediammonium bromide (TMHEDAB) was investigated using the water-soluble initiator PDS (potassium peroxydisulphate) and water-insoluble solvent ethylacetate in an aqueous-organic biphase system at 60±1°C under nitrogen atmosphere at fixed pH and ionic strength. Rp increased with the increase in concentration of the monomer, initiator and catalyst. The order of R_p, with respect to monomer and catalyst concentration was found to be unity and with respect to initiator was found to be 0.5. A suitable mechanism has been proposed and its significance was discussed. The polymers obtained were characterized by spectral studies such as FTIR, ¹H-NMR, XRD, DSC, and TGA.     

对氯甲基苯乙烯共聚物引发甲基丙烯酸甲酯原子转移自由基聚合

通过偶氮二异丁氰(AIBN)引发苯乙烯(St)与对氯甲基苯乙烯(p-CMS)共聚,合成了二元共聚物P(St-co-CMS),在氯化亚铜/四甲基乙二胺(CuC l/TMEDA)催化下,以此二元共聚物为大分子引发剂引发甲基丙烯酸甲酯(MMA)的原子转移自由基聚合(ATRP),成功地合成了结构明晰的以聚苯乙烯为主链、聚甲基丙烯酸甲酯为支链的接枝共聚物P(S-g-MMA)。大分子引发剂和接枝共聚物的结构通过红外光谱(IR)、核磁共振氢谱(1HNMR)得到了确认,并测定了接枝共聚物的平均支链数目、平均支链长度、接枝率及接枝效率。结果表明,用这种方法制备的接枝共聚物相对分子质量分布较窄,支链数目及长度可控,接枝效率高达93.7%。     

原子转移自由基聚合在制备新型材料中的应用

原子转移自由基聚合（ATRP）技术是一种新型的可控活性聚合技术,可有效地对聚合物的分子结构进行设计,制备出各种不同性能、不同组成、不同功能化的结构确定的聚合物材料。综述了利用ATRP技术在制备有机一无机杂化材料、功能性膜材料、水凝胶材料、液晶材料方面的最新进展,最后对原子转移自由基聚合技术的发展做出了展望。     

Synthesis and Characterization of Polystyrene-b-Poly(4-vinyl pyridine) Block Copolymers by Atom Transfer Radical Polymerization

We aimed at the synthesis of well-define PS-b-P4VP by using atom transfer radical polymerization in two-step process. First, polystyrenes with benzyl bromide end group (PS-Br; by ATRP) were prepared as macroinitiator for the next ATRP of 4-vinyl pyridine and characterized these polymers from ¹H-NMR and MALDI-TOF. Comparing with MALDI-TOF-MS, ¹H-NMR and GPC analyses, this indicates that the formation of the block copolymer can be observed. During the polymerizations, molecular weight distribution and kinetics have been evaluated from GPC traces and ¹H-NMR analyses. We further characterized the thermal properties of these block polymers by DSC and TGA. DSC measurement on the PS-b-P4VP block copolymers exhibited two glass transitions, indicating that the resulting block copolymers are phase separated. Two maxima differential peaks were observed on the TGA trace for the PS-b-P4VP block copolymers might be assigned to the decomposition of the P4VP blocks at 380 ^○C and the PS blocks at higher temperature.     

活性自由基聚合法合成偶氮聚合物研究进展

偶氮聚合物具有光致顺反异构和光学各向异性,其在光电信息技术领域具有重要的潜在应用前景.利用活性自由基聚合的方法可以在温和的条件下合成得到特定结构与预定相对分子质量的偶氮聚合物.综述了该技术领域的最新研究进展,并对近年来出现的聚合体系与方法,包括氮氧稳定自由基聚合(NMP)、原子转移自由基聚合(ATRP)、可逆加成一断裂链转移(RAFT)聚合等,作了简要的评述.     

吡啶基三唑配合物催化下甲基丙烯酸甲酯的原子转移自由基聚合研究

以配体3,5-二-(4-吡啶基)-1,2,4-三唑与CuX形成催化剂,分别以α-溴代异丁酸乙酯和氯化苄为引发剂,环己酮为溶剂,进行了甲基丙烯酸甲酯(MMA)的原子转移自由基聚合(ATRP),同时考察了配比、溶剂量以及温度对聚合速率、聚合物分子量及分子量分布的影响.80℃下的聚合反应速度高于70℃;以环己酮为溶剂,单体与溶剂之比为1∶1.5时可得到较低分子量分布的聚合物.实验结果表明以吡啶基三唑为配合物催化甲基丙烯酸甲酯的聚合过程中,转化率和分子量随时间的增加而增大,聚合反应符合一级动力学规律,所得聚合物分子量分布较窄(1.21～1.46),结合端基分析和扩链反应结果,证明该聚合反应符合"活性"/可控自由基聚合.     

ATRP合成线性苯乙烯-丙烯腈共聚物

以α-溴代异丁酸叔丁酯(t-BBiB)为引发剂,CuBr/2,2′-联二吡啶(Bpy)为催化体系,在70℃下经原子转移自由基聚合(ATRP)反应进行苯乙烯(St)和丙烯腈(AN)共聚合合成苯乙烯/丙烯腈共聚物。采用GC、~1H NMR和GPC对聚合反应过程和聚合产物进行了分析和表征。结果表明:单体浓度的半对数曲线与聚合时间呈线性关系,聚合物摩尔质量随单体转化率的上升而线性增加,而且摩尔质量分布在1.2～1.3之间,表现出活性聚合反应特征。随着聚合反应的进行,共聚物组成趋向于原始单体组成,大分子链存在梯度结构。     

Using Atom Transfer Radical Polymerization for the Synthesis of Grafted PVDF Copolymers towards the Synthesis of Membranes

Graft copolymers of poly(vinylidene fluoride) (PVDF) with poly(3-sulfopropyl methacrylic acid) (PVDF-g-PSPMA), poly(styrene-4-sulfonic acid) (PVDF-g-PSSA), and poly(dimethylaminoethyl methacrylate) (PDVFg-PDMAEMA) were synthesized. The aforementioned grafted copolymers were prepared from the corresponding (PDVF-g-PSPMPS) poly(3-sulfopropyl methacrylate potassium) and (PVDF-g-PSSS) poly(styrene-4-sulfonate sodium) salts using PVDF as a macroinitiator for atom transfer radical polymerization (ATRP). The copolymers were casted into membranes by the phase inversion method in aqueous media. The effects of polymerization time, degree of conversion, chain transfer agent (CTA) additive, crosslink process, and various solvents were investigated. The products were characterized by ¹H and ¹³C NMR spectroscopy, IR spectroscopy, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The maximum grafting incorporation was up to 26, 20 and 20 wt % for PSSA, PSPMA and PDMAEMA, respectively. The incorporation was reduced using a CTA additive. The most impressive feature of the graft copolymer membranes produced in this study are the improved water fluxes and polyethylene glycol (PEG) rejection properties when compared to the commercially available, pristine PVDF.     

Preparation and Characterization of Novel Poly(Urethane-Imide) Nanocomposite Based on Graphene,Graphene Oxide and Reduced Graphene Oxide

In this work in-situ preparation of novel poly(urethane-imide)/graphene, graphene oxide and reduced graphene oxide nanocomposite is reported by the reaction of 4,4´-diphenylmethane diisocyanate, polypropylene glycol, 3,3’,4,4′-benzophenone tetra carboxylic dianhydride and nanomaterials in the loadings levels of 0.5, 1.5, 2.5, and 3.5 pbw in propylene carbonate as an alternative green solvent. The synthesized poly(urethane-imide) nanocomposite was characterized by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (¹HNMR), thermogravimetric analysis (TGA), attenuated total reflection (ATR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC), respectively. The resulting nanocomposite showed enhanced thermal stability when compared with pristine and unfilled poly(urethane-imide) sample.     

原子转移自由基聚合在树形聚合物合成中的应用

原子转移自由基聚合(ATRP)技术是一种新型的可控/活性聚合技术,可有效地对聚合物的分子结构进行设计,制备出各种不同性能、不同组成、不同功能化的结构确定的聚合物。综述了利用ATRP技术合成树枝状-线性嵌段共聚物、类树枝状聚合物(dendrimer-like polymer)、具有刺激-响应性末端基团的树枝状聚合物、树枝状-星型嵌段共聚物和基于树枝状聚合物的聚合物刷的研究进展。     

甲基丙烯酸-N, N-2-甲基乙胺酯原子转移自由基聚合动力学研究

A kinetic model was developed to describe the atom transfer radical polymerization (ATRP) of 2-(N,N-dimethylamino) ethyl methacrylate (DMAEMA). The model was based on a polymerization mechanism, which included the atom transfer equilibrium for primary radical, the propagation of growing polymer radical, and the atom transfer equilibrium for the growing polymer radical. An experiment was carried out to measure the conversion of monomer, the number-average molecular weight of polymer and molecular weight distribution for the ATRP process of DMAEMA. The experimental data were used to correlate the kinetic model and rate constants were obtained. The rate constants of activation and deactivation in the atom transfer equilibrium for primary radical are 1.0 × 104 L·mol-1·s-1 and 0.04L·mol-1·s-1, respectively. The rate constant of the propagation of growing polymer radical is 8.50L·mol-1·s-1, and the rate constants of activation and deactivation in the atom transfer equilibrium for growing polymer radica     

甲基丙烯酸-N,N-2-甲基乙胺酯原子转移自由基聚合动力学研究

A kinetic model was developed to describe the atom transfer radical polymerization (ATRP) of 2-(N,N-dimethylamino) ethyl methacrylate (DMAEMA). The model was based on a polymerization mechanism,which included the atom transfer equilibrium for primary radical, the propagation of growing polymer radical, and the atom transfer equilibrium for the growing polymer radical. An experiment was carried out to measure the conversion of monomer, the number-average molecular weight of polymer and molecular weight distribution for the ATRP process of DMAEMA. The experimental data were used to correlate the kinetic model and rate constants were obtained. The rate constants of activation and deactivation in the atom transfer equilibrium for primary radical are 1.0 x 104 L·mol-1.s-1 and 0.04 L·mol-1.s-1, respectively. The rate constant of the propagation of growing polymer radical is 8.50 L·mol-1.s-1, and the rate constants of activation and deactivation in the atom transfer equilibrium for growing polymer radical are 0.045 L.mol-1.s-1 and 1.2 × 105 L·mol-1.s- 1, respectively. The values of the rate constants represent the features of the ATRP process. The kinetic model was used to calculate the ATRP process of DMAEMA. The results show that the calculations agree well with the measurements.     

Atom transfer radical polymerization of styrene initiated by 2-(4-chloromethyl-phenyl)-benzoxazole with high activity and fluorescent property

Functionalized polystyrene (PSt) was synthesized utilizing atom transfer radical polymerization (ATRP), which was conducted by using 2-(4-chloromethyl-phenyl)-benzoxazole (CMPB) as initiator, CuCl/PMDETA as catalyst, and cyclohexanone as solvent. The mechanism of ATRP was proved by characterizing the structure of PSt via ¹H NMR and preparing of PSt-b-PMMA block copolymer. The polymerization showed first order with respect to monomer concentration and relatively narrow polydispersity (M_w/M_n range from 1.30 to 1.50). Factors such as different reaction temperatures, mole ratio of monomer to initiator and so on, which can affect the ATRP system, were discussed in the paper. Moreover, CMPB showed high activity and could initiate styrene polymerization even at ambient temperature. The optical property of initiator was well preserved in the obtained PSt, and the end-functionalized PSt exhibited strong fluorescent emission at 351 nm.     

Synthesis of poly(ethylene oxide)-block-poly(methyl methacrylate)-block-polystyrene triblock copolymers by two-step atom transfer radical polymerization

The synthesis of ABC triblock copolymer poly(ethylene oxide)-block-poly(methyl methacrylate)-block-polystyrene (PEO-b-PMMA-b-PS) via atom transfer radical polymerization (ATRP) is reported. First, a PEO-Br macroinitiator was synthesized by esterification of PEO with 2-bromoisobutyryl bromide, which was subsequently used in the preparation of halo-terminated poly(ethylene oxide)-block-poly(methyl methacrylate) (PEO-b-PMMA) diblock copolymers under ATRP conditions. Then PEO-b-PMMA-b-PS triblock copolymer was synthesized by ATRP of styrene using PEO-b-PMMA as a macroinitiator. The structures and molecular characteristics of the PEO-b-PMMA-b-PS triblock copolymers were studied by FT-IR, GPC and ¹H NMR.     

Dendrigraft polystyrene initiated by poly(p-chloromethyl styrene): synthesis and properties

Dendrigraft polystyrene was prepared using poly(p-chloromethyl styrene) as the multicentre initiator by atom transfer radical polymerization (ATRP). The resulting polymer was characterized with light scattering, intrinsic viscosity, thermal analysis and atomic force microscopy (AFM) imaging. The AFM image showed there were two kinds of different structural dendrigraft polystyrenes in the product, ie the ‘coupling’ dendrigraft polystyrene and ‘free’ dendrigraft polystyrene. The ‘coupling’ structure might result from the coupling reaction of growing radical chain ends. The second virial coefficient A₂ and intrinsic viscosity of the dendrigraft polystyrene were smaller than those of the relative linear and twelve-arm star polystyrene, and the thermal analysis showed that the initial decomposition temperature was a little higher than that of linear polystyrene. © 1999 Society of Chemical Industry