Copper(0)‐mediated radical copolymerization of vinyl acetate and acrylonitrile in DMSO at ambient temperature

In this work, Cu(0)‐mediated radical copolymerization of vinyl acetate (VAc) and acrylonitrile (AN) was explored. The polymerization was carried out at 25°C with 2,2′‐bipyridine as ligand and dimethyl sulfoxide as solvent. The copolymerization proceeded smoothly producing moderately controlled molecular weights at low VAc feed ratios. The high VAc feed ratios generated low polymerization rate and poorly controlled molecular weights. FTIR, ¹H NMR, and differential scanning calorimetry confirmed the successful obtaining of the copolymers. Based on ¹H NMR spectra, the reactivity ratios of VAc and AN were calculated to be 0.003 and 1.605, respectively. This work conveyed the first example for the Cu(0)‐mediated radical polymerization of AN and VAc, wherein VAc cannot be homopolymerized by Cu(0)‐mediated radical polymerization technique. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Thermal,flexural, and impact strength studies on phenolic novolac resin/acrylonitrile–butadine rubber blends

Phenolic novolac resin was modified with nitrile rubber (NBR) using resol as compatibilizer. These systems were characterized by differential scanning calorimetry, flexural and impact strength. The resin was prepared by varying percentage of NBR. The curing behavior of unmodified and NBR-modified phenolic resin has been studied. The results reveal that the exothermic heat of cure for NBR-modified system increases due to the participation of the double bond of butadiene. In addition, the impact strength and flexural strain increase with increasing percentage of NBR in the phenolic resin matrix.     

Fast copper catalyzed living radical polymerization of acrylonitrile utilizing a high concentration of radical initiator

This article first reports a fast and controlled living radical polymerization (LRP) of acrylonitrile, evidenced by 81.3% monomer conversion within 40 min and well‐defined the polymers with a narrow polydispersity index (PDI) range of 1.14?1.38. This was achieved by utilizing azobis(isobutyronitrile) as radical initiator with a high concentration up to 190 mM and CuBr₂ as catalyst with a very low concentration down to 50 ppm. The polymerization displayed typical LRP characteristics, including pseudo first‐order kinetics of polymerization, the linear increase of number‐average molecular weights (MWs), low PDI values. The influence of various experimental components, radical initiator concentration, catalyst concentration, and reaction temperature, on the polymerization reaction and MW as well as PDI has been investigated in detail. ¹H NMR and gel permeation chromatography analyses as well as chain extension reaction confirmed the very high chain‐end functionality of the resultant polymer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

气相色谱–质谱联用法测定空气中的丙烯腈

建立测定空气中丙烯腈的气相色谱–质谱联用方法。用活性炭管采集样品,以体积分数为2%的丙酮二硫化碳溶液解吸,利用气相色谱–质谱法以选择离子扫描方式采集数据并进行分析,以色谱峰面积外标法定量。丙烯腈的质量浓度在0~100μg/m L范围内与色谱峰面积线性关系良好,线性相关系数(r~2)为0.999 0。丙烯腈检出限为1.2μg/m L,最低检出质量浓度为0.16 mg/m~3(以采样体积7.5 L计),平均加标回收率为97.0%~99.3%,测定结果的相对标准偏差为3.0%~4.2%(n=6)。该方法定性、定量准确,精密度、灵敏度高,可用于空气中丙烯腈的常规检测。     

Application of Crosslinked Acrylamidoxime/2-Acrylamido-2-methylpropane Sulfonic Acid Copolymer in Wastewater Treatment

Crosslinked acrylonitrile/acrylamidoxime/2-acrylamido-2-methylpropane sulfonic acid (AN/AAx/AMPS) based hydrogels was prepared by radical solution polymerization technique. The structures of hydrogels were characterized by FTIR analysis and the results were consistent with the expected structures. These hydrogels were used for the separation of Cd(II), Cu(II), and Fe(III) ions from their aqueous solutions. The influence of the uptake conditions such as pH, time, and initial feed concentration on the metal ion binding capacity of hydrogel was also tested. The selectivity of the hydrogel toward the different metal ions tested was Cd(II)>Fe(III)>Cu(II). The recovery of metal ions was also investigated in acid media.     

An Electrogenerated Base-Promoted Synthesis of 2-Aryl-3,3-Bis((Perfluoroalkyl) Thio)Acrylonitriles

Abstract

The preparation of 2-aryl-3,3-bis((perfluoroalkyl)thio)acrylonitriles is described. The electrogenerated cyanomethyl base/anion obtained from electroreduction of acetonitrile promotes reactions between arylacetonitrile, carbon disulfide, and perfluoroalkyl iodides. The new fluorinated acrylonitriles were obtained in good yields under mild reaction conditions.     

FeCl3/Acetic Acid-mediated Reverse Atom Transfer Radical Polymerization of Acrylonitrile

Reverse atom transfer radical polymerization (RATRP) has been successfully applied in the synthesis of polyacrylonitrile (PAN) with FeCl₃/acetic acid as catalyst in the presence of conventional initiator azobisisobutyronitrile (AIBN) at 65°C in N,N-dimethylformamide (DMF). A FeCl₃ to acetic acid ratio of 1:2 not only gave better control on polymer's molecular weight and its distribution, but also provided a rapid polymerization rate compared with any other molar ratio of FeCl₃ to acetic acid. The polymerization rate increased with increasing temperature and the apparent activation energy was calculated to be 80.6 kJ·mol^?1. In comparison with dimethyl sulfoxide, acetonitrile, cyclohexanone and ethyl acetate, DMF was considered to be the best solvent of the polymerization for its polarity. Analysis of ¹H-NMR further confirmed the living nature of the polymerization.     

Samarium(III)-based AGET ATRP of Acrylonitrile Using Ascorbic Acid as Reducing Agent

Atom transfer radical polymerization using activators generated by electron transfer (AGET ATRP) of acrylonitrile (AN) initiated by ethyl 2-bromoisobutyrate (EBiB) was approached for the first time in the absence of oxygen and in the presence of air, using a novel catalyst system based on SmBr₃·6H₂O/isophthalic acid complexes and using ascorbic acid (VC) as a reducing agent. Both the polymerization in the absence of oxygen and in the presence of air proceeded in a well-controlled manner as evidenced by kinetic studies. Compared with the polymerization in the absence of oxygen, the polymerization in the presence of air provided rather slow reaction rate and showed better control of molecular weight and its distribution under the same experimental conditions. The polymerization apparent activation energies in the absence of oxygen and in the presence of air were calculated to be 47.1 and 51.3 kJ·mol^?1, respectively. A slow polymerization rate and a broad polydispersity index were observed using anisole and toluene instead of DMF as solvent. Polyacrylonitrile obtained was successfully used as a macroinitiator to proceed the chain extension polymerization of styrene via AGET ATRP in the presence of air.     

Transition structures and reaction barriers in the styrene–acrylonitrile copolymerization system according to quantum mechanical calculations

The geometries and electronic properties of substrates, transition structures (TS), and product radicals in modeled elementary propagation reactions were studied for the styrene–acrylonitrile monomer system by use of quantum‐mechanical calculations: (DFT/B3‐LYP/6–31G(d), ROMP2/6–311+G(3df,2p)//DFT/B3‐LYP/6–31G(d), and DFT/B3‐LYP/6–311+G(3df,2p)//DFT/B3‐LYP/6–31G(d)) and for some parameters, the high‐level composite method G3 (Gaussian‐3, G3/MP2). Activation enthalpies (ΔH^act) and reaction enthalpies (ΔH_r) for modeled propagation reactions at 298.15 K were evaluated. The enthalpy of activation energy (ΔH^act, kJ/mol) for the investigated elementary reactions rises for the B3‐LYP calculation in the following order: (CH₃A?+S) < (CH₃A?+A) < (CH₃S?+A) < (CH₃S?+S). For three propagation reactions, (CH₃A?+A), (CH₃A?+S), and (CH₃S?+A), correlation between reaction enthalpy and enthalpy of activation suggests weak or negligible polar effects reflecting the Evans–Polanyi relation. However, from the electron affinities and ionization energies values data, it is not excluded that at least for [CH₃A?+S[b]] and [CH₃S?+A[b]] reactions, nucleophilic and electrophilic polar effects, respectively, can also be expected. The dependencies between TS geometries, electronic parameters, and enthalpic effects suggest the presence of a steric factor in all TS, including its exceptionally high contribution to the activation enthalpy for the CH₃S?+S addition. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1827–1844, 2005     

Synthesis and Characterization of the Polyacrylonitrile-block-poly（methyl acrylate） by RAFT Technique

Reversible addition-fragmentation chain transfer polymerization (RAFT) was firstly reported in 1998 by Rizzardo1. This technique provided the possibility to synthesize polymers with controlled molecular weight, narrow molecular weight distribution, and we…