SYNTHESIS AND POLYMERIZATION OF α-METHACRYLYOXYLETHYLOXYCARBONYLMETHYL-ω-(N,N-DIETHYLDITHIOCARBAMYL)POLYSTYRENE MACROMONOMERS

Polystyrene macromonomers with different molecular weight were prepared by radical polymerization of styrene(St) in benzene using β-methacryloxylethyl 2-N,N-diethyldithiocarbamylacetate (MAEDCA) as a monomer-iniferter.Characterization of the macromonomer by ~1H-NMR showed that the end groups were α-methacrylyoxylethyloxycarbonyl-methyl and ω-(N,N-diethyldithiocarbamyl). The macromonomer was difficult to homopolymerize, but it was easilycopolymerized with methyl methacrylate (MMA) initiated by AIBN to form graft copolymers (PMMA-g-PSt) with PStbranches randomly distributed along the PMMA backbone. Copolymerization reaction and the structure of the graftcopolymers were strongly affected by M_n and concentration of the macromonomer. The composition and M_n of the purified graft copolymer were determined by ~1H-NMR and GPC analysis.     

奋乃静和有机过氧化物引发体系及含奋乃静的缓释药膜

研究了含叔胺基结构的药物奋乃静（Ｐｅｒｐｈｅｍｎａｚｉｎｕｍ，简称ＰＥＲＰ）和有机过氧化物所构成的引发体系，并以此体系引发丙烯酸酯类单体聚合所得的含奋乃静缓释药膜的缓释行为．结果表明，奋乃静（ＰＥＲＰ）和过氧化苯甲酰（ＢＰＯ）引发体系引发甲基丙烯酸甲酯（ＭＭＡ）聚合的动力学方程为：Ｒｐ＝Ｋｐ［ＢＰＯ］０５［ＰＥＲＰ］０５［ＭＭＡ］１０，聚合表观活化能Ｅａ＝４１８ＫＪ／ｍｏｌ，从而确定此引发体系的引发机理为氧化还原引发机理．ＰＥＲＰ ＢＰＯ体系能在４０℃温度下，引发丙烯酸酯类单体共聚，而能形成含有奋乃静的缓释药膜     

Acrylonitrile Polymerization by Ceric lon-Primary Alcohol Redox Systems in Aqueous Nitric Acid

The polymerization of acrylonitrile (AN) initiated by Ce^IV-primary alcohol redox systems has been studied in aqueous nitric acid under nitrogen in the temperature range 0 to 45° C. Taft's correlation can be applied to fit the kinetic results relative to a series of differently substituted primary alcohols. The polymerization is initiated by primary radicals formed in water from the dismutation of the Ce^IV -alcohol complex, This process has a high activation energy (21 kcal/mol) and gives rise to an induction period at temperatures lower than 40° C. PAN chains containing the alcohol residue are terminated predominantly on metal ions. The alcohol enhances the AN solubility in water and accordingly influences the polymerization kinetics. Variations in temperature and concentration of both components of the redox system allow control of the polymerization rate and of the molecular weight of the resulting PAN.     

Optimization of amine-terminated polyacrylonitrile synthesis and characterization

Amine-terminated PANs were prepared in two steps. The first step includes free radical polymerization of acrylonitrile (AN) using initiator pair of ammonium persulfate and sodium thiosulfate as redox system. In the second step, the amino groups were introduced through the reaction of polyacrylonitrile with excess of different diamines (10-fold) including ethylenediamine (EDA), hexamethylenediamine (HMDA) and octamethylenediamine (OMDA), to yield PAN–EDA, PAN–HMDA and PAN–OMDA, respectively. Optimization of the amine-terminated PANs synthesis was carried out at different temperatures (30–90 °C) and different time intervals (4–24 h). In addition, the introduction of the amino group was followed by the piperidine test and recording of the FT-IR spectra. All polymers were characterized by, ¹H NMR spectra, thermogravimetric analysis (TGA), and FT-IR spectra.     

VINYL RADICAL POLYMERIZATION INITIATED WITH CERIC ION AND N-(SUBSTITUTED PHENYL) ACETAMIDE SYSTEMS

The polymerization of acrylamide (AAM)in H_2O/DMF or in H_2O/CH_3CN mixed solvent initiated with ceric ion (Ce~(4+) )/N-(substituted phenyl)-acetamide systems have been studied. The redox polymerization was revealed by the low value of overall activation energy (E_α) of AAM polymerization using ceric ion/N-(substituted phenyl) acetamide system as an initiator. The end group of polymer formed was detected by IR spectrum analysis method, it revealed the presence of N-(m-acetoxy-methylphenyl) acetamide (m-AAe) moiety end group in the polymer obtained with ceric ion/m-AAe initiation system.     

Thermal Analysis of Acrylonitrile Polymerization and Cyclization in the Presence of N,N-Dimethylformamide

This paper examines the polymerization of acrylonitrile to poly(acrylonitrile)(PAN), and its cyclization, in bulk form and using N,N-dimethylformamide (DMF) as solvent in which both monomer and polymer are soluble. Thermal analysis of the resultant products after polymerization has been performed by DSC and pyrolysis gas chromatography/mass spectrometry (Py-GC/MS). Scanning electron microscopy has been used to study the morphology of the resultant products and after thermal treatments. The DSC thermal curve of PAN-DMF sample is quite different from the PAN bulk sample, showing a single sharp exothermic peak associated with nitrile group polymerization (cyclization) of PAN at lower temperature (240°C) than that of bulk PAN sample (314°C). Cyclization of PAN was confirmed by IR spectroscopy. It was found that the amide molecules are difficult to eliminate completely in the product obtained after the polymerization reaction, even after prolonged heating at 110°C, and remain occluded. The formation of a complex by dipolar bonding is also possible and it is discussed. It is concluded that the amount of heat evolved as well as the temperature interval over which it is released are influenced by the chemical processing of PAN when using DMF as solvent of both monomer and polymer. Pyrolysis of these PAN samples revealed the release of occluded molecules of DMF, and several compounds containing nitrogen produced from the thermal degradation processes. All these results are interesting to know the chemical processing of carbon fibres and activated carbon fibres from PAN modified precursors.This revised version was published online in November 2005 with corrections to the Cover Date.     

AGET ATRP of acrylonitrile using 1,1,4,7,10,10‐hexamethyltriethylenetetramine as both ligand and reducing agent

Atom transfer radical polymerization using activators generated by electron transfer (AGET ATRP) of acrylonitrile (AN) initiated by ethyl 2‐bromoisobutyrate was approached for the first time using 1,1,4,7,10,10‐hexamethyltriethylenetetramine (HMTETA) and 1,1,4,7,7‐pentamethyldiethylenetriamine (PMDETA) as both ligand and reducing agent. AGET ATRP of AN with HMTETA as both ligand and reducing agent was better controlled than with PMDETA as both ligand and reducing agent under the same experimental conditions. With an increase content of HMTETA, the polymerization provided an accelerated reaction rate and a broader polymer molecular weight distribution. The rate of polymerization with DMF as solvent was faster than with acetonitrile, cyclohexanone, toluene, and xylene as solvents. The polymerization apparent activation energy was calculated to be 45.7 kJ mol^?1. The end functionality of polyacrylonitrile (PAN) was confirmed by ¹H NMR spectroscopy. The living feature of PAN was verified by chain extensions of PAN with methyl methacrylate and AN. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 128–133, 2010     

Studies on the structure and resistance to thermooxidation of graft copolymer of polycaproamide with polyacrylonitrile and sulfur-containing derivatives

By the methods of infrared and mass spectroscopy, the structure of grafted copolymer of polycaproamide (PCA) with polyacrylonitrile (PAN) was examined. It is shown on the grounds of analysis of infrared absorption bands and mass spectrum of the volatile products of grafted copolymer thermodestruction that the graft copolymerization in the redox system Fe⁺³/H₂O₂ is carried out at the expense of the radicals, formed on COOH groups of PCA. The structure of grafted chains PAN changes owing to formation of cycles containing ? S? and C?N groups at the grafted copolymer treatment with Na₂S. By the means of complex thermal analysis, the steadiness of the obtained products to thermooxidizing destruction was investigated. It was found that the presence of sulfur in the grafted copolymer PCA–PAN considerably intensifies the processes of grafted-chain PAN cyclization as compared with the PAN homopolymer. It was shown that Na₂S treatment brings to the product with the minimized absorption of oxygen at the isothermal heating that indicates its stability with regard to thermooxidizing destruction     

叔胺中的取代基团对其促进烯类聚合活性的影响

<正> 过硫酸盐和水溶性脂肪胺可以组成引发体系用于烯类聚合反应。脂肪胺的促进聚合活性随其结构不同而异。为了研究清楚脂肪胺促进聚合活性与结构的关系,本文合成了几种甲基取代的脂肪叔胺,分别与过硫酸盐组成引发体系用于烯类聚合反应。研究结果表明,甲基取代基团的效果较好。     

Polymerization of methyl methacrylate with ceric ion-methanol redox system

The polymerization of methyl methacrylate initiated by Ce⁴⁺ methanol redox system was studied in aqueous solution of nitric acid at 15°C. The polymerization was initiated by primary radicals formed from Ce⁴⁺/alcohol complex. Poly(methyl methacrylate) chains containing the alcohol residue were obtained. Variations in the temperatuare and concentration of the components of the redox system allowed the control of the rate of polymerization and molecular weight of the polymer. The concentration of the hydroxyl end groups in the poly(methyl methacrylate) of low molecular weight was determined by titration and by spectrometric method.     

Emulsion polymerization of vinyl acetate initiated by potassium persulfate-cyclohexanone sodium bisulfite redox pair system

The emulsion polymerization of vinyl acetate using potassium persulfate and cyclohexanone sodium bisulfite as redox pair initiation system was studied. The rate of polymerization, maximum conversion, and the number of polymer particles produced were found to change with redox initiator, monomer and emulsifier concentrations, and temperature variation. The rate of polymerization was found to be dependent on the initiator, the monomer, and the emulsifier concentrations to the 0.88, 0.22, and 0.20 powers, respectively. The K₂S₂O₈–NaHSO₃ redox system was found to decrease maximum conversion and doesn't form a stable emulsion. The apparent arrhenius activation energy (E^a) estimated for the polymerization system was 65.6 kJ/mol. The viscosity average molecular weights for some obtained poly(vinyl acetate) were determined.     

N-(4-苯甲酰苯基)衣康酰亚胺与甲基丙烯酸-N,N-二甲氨基乙酯组成的可聚合光氧化还原体系引发的丙烯腈光聚合

Ｎ （４ 苯甲酰苯基）衣康酰亚胺与甲基丙烯酸 Ｎ，Ｎ 二甲氨基乙酯组成的可聚合光氧化还原体系引发的丙烯腈光聚合高青雨杨更须崔元臣张福莲张举贤（河南大学化学化工学院开封４７５００１）李福绵（北京大学化学系北京１００８７１）关键词Ｎ （４ 苯甲酰苯基）...     

等离子体聚合法修饰半导体光电极的研究——聚丙烯腈/n-GaAs,n-GaP电极

Polyacrylonitrile (PAN) film attached to n-GaAs, n-GaP photoelectrode surface by plasma polymerization has been studied. Both electrochemical behaviors and stability of the modified electrodes have been investigated. The results showed that the semiconductor electrodes with PAN film decreased photocorrosion in a certain degree, and their electrochemical characteristics and stability were improved remarkably after plasma doping. Cyclic voltammetric analysis demonstrated that the redox reaction occurred in I-PAN films could be carried out rapidly on electrode surfaces, in favor of the capture and transfer of photoinduced holes by the films to redox couples in solution.     

Synthesis of polyacrylonitrile by single‐electron transfer‐living radical polymerization using Fe(0) as catalyst and its adsorption properties after modification

Fe(0) was firstly used as single‐electron transfer‐living radical polymerization catalyst for acrylonitrile polymerization using carbon tetrachloride as initiator, hexamethylenetetramine as N‐ligand, and N,N‐dimethylformamide as the solvent at 65 °C. First‐order kinetic studies indicated that this polymerization proceeded in a “living”/controlled manner. The living nature of the polymerization was also confirmed by chain extension of methyl methacrylate with polyacrylonitrile (PAN) as macroinitiator. Furthermore, PAN was modified with NH₂OH·HCl to generate amidoxime groups for extraction of heavy metal ions (Hg²⁺) from aqueous solutions. Fourier transformed infrared spectroscopy was performed to characterize chemical composition and structure. The adsorption property of Hg²⁺ was investigated at different pH values of aqueous solutions and distilled water. The maximal saturated adsorption capacity of Hg²⁺ was 4.8 mmol g^?1. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Living radical polymerization of acrylonitrile catalyzed by copper with a high concentration of radical initiator and its application in removal of Ag(I) after modification

In this study, we reported the synthesis of polyacrylonitrile (PAN) via living radical polymerization in N, N‐dimethylformamide using carbon tetrachloride as initiator, copper(II) chloride (CuCl₂)/hexamethylenetetramine as catalyst system, and 2,2‐azobisisobutyronitrile as a high concentration of thermal radical initiator. The polymerization proceeded in controlled/living manner as indicated by first‐order kinetics of the polymerization with respect to the monomer concentration, linear increase of the molecular weight with monomer conversion and narrow polydispersity. Higher polymerization rate and narrower molecular weight distributions were observed with CuCl₂ less than 50 ppm. The rate of polymerization showed a trend of increase along with temperature. The modified PAN containing amidoxime group was used for extraction of Ag(I) ions from aqueous solutions. The adsorption kinetics data indicated that the adsorption process followed pseudo‐second‐order rate model. The isotherm adsorption process could be described by the Freundlich isotherm model. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Reverse Atom Transfer Radical Polymerization of Acrylonitrile Catalyzed by FeCl3/Lactic Acid

Reverse atom transfer radical polymerization (RATRP) of acrylonitrile (AN) was carried out using azobisisobutyronitrile (AIBN) as initiator, ferric trichloride anhydrous (FeCl₃)/lactic acid (LA) as catalyst system; a ratio of FeCl₃/LA was 1:2 gave the best control. RATRP of AN with N,N-dimethylformamide (DMF) as solvent gave the moderate polymerization rate and the narrowest polydispersity index (PDI). When FeCl₃ was replaced by CuBr₂, RATRP of AN showed a longer induction period. When Cu was added to the CuBr₂-based catalyst system, the induction period was reduced. ¹H-NMR spectra of PAN verified the possibility of controlled/living polymerization for future chain extension.     

Radical polymerization of ethyl acrylate with dead end polymerization conditions

The radical polymerization of ethyl acrylate (EA) with 4,4^′-azobis(4-cyanovaleric)acid as initiator was investigated in propionitrile at 363 K in order to obtain carboxy-telechelic oligo(ethyl acrylate). The results of functionality and molecular weights showed that a transfer reaction had occurred. A molecular weight study was performed in order to show the importance of transfer to solvent due to the high reactivity of the EA radical. Finally, the radical polymerization was investigated at very low temperature (253-273 K), using a redox system initiation. A behavior of dead end polymerization was observed but the activation energy of propagation for EA is still high and does not allow the synthesis of a telechelic oligomer.     

Application of polyacrylonitrile-based polymer electrolytes in rechargeable lithium batteries

Polyacrylonitrile (PAN)-based polymer electrolytes have obtained considerable attention due to their fascinating characteristics such as appreciable ionic conductivity at ambient temperatures and mechanical stability. This study is based on the system PAN–ethylene carbonate (EC)–propylene carbonate (PC)–lithium trifluoromethanesulfonate (LiCF₃SO₃). The composition 15 mol% PAN–42 mol% EC–36 mol% PC–7 mol% LiCF₃SO₃ has shown a maximum room temperature conductivity of 1.2?×?10^?3 S cm^?1. Also, it was possible to make a thin, transparent film out of that composition. Cells of the form, Li/PAN–EC–PC–LiCF₃SO₃/polypyrrole (PPy)–alkylsulfonate (AS) were investigated using cyclic voltammetry and continuous charge–discharge tests. When cycled at low scan rates, a higher capacity could be obtained and well-defined peaks were present. The appearance of peaks elucidates the fact that redox reactions occur completely. This well proves the reason for higher capacity. The average specific capacity was about 43 Ah kg^?1. Cells exhibited a charge factor close to unity during continuous charging and discharging, indicating the absence of parasitic reactions.     

新型引发转移终止剂引发烯类单体活性自由基聚合及共聚合

引发转移终止剂 (Iniferter)是最早实现活性自由基聚合的方法 ,尽管它对聚合过程控制得不是很好 ,但是可聚合单体多 ,能方便地制备接枝和嵌段共聚物 .因此 ,近 2 0年来 ,它一直是高分子合成化学领域的一个研究热点 ,许多新颖结构的引发转移终止剂被合成并用于制备端基功能化聚合物、遥爪聚合物、大分子单体以及接枝和嵌段聚合物等 .本文扼要综述了引发转移终止剂的发展 ,着重综述了我们研究组在C—C键型高活性热引发转移终止剂、新的光引发转移终止剂、可聚合光引发转移终止剂、新型多功能引发转移终止剂和大分子光引发转移终止剂 5个方面的研究进展     

Preparation of hole transporting polymers by condensation polymerization of triphenylamine derivatives

Hole transporting polymers were prepared by condensation polymerization of triphenylamine and N,N,N',N'‐tetraphenylbenzidine (TPD) having alkyl group with aldehydes in the presence of p‐toluenesulfonic acid. The obtained polymers had molecular weight higher than 10,000 and good film formation ability. It was found that the aromatic amine monomers were connected with aldehyde monomer at the p‐position of the phenyl group. TPD‐aldehyde polymers had almost the same UV absorption and redox potentials as those of TPD monomer indicating that the electronic structure of amine unit did not change by the polymerization. The hole transporting mobility was in the range of 10⁻³‐10⁻⁶cm²/Vs. The electroluminescent device consisting of ITO/TPD polymer/Alq/Mg‐Ag had a maximum luminance of 9000 cd/m².