Radical Copolymerization of Acrylonitrile with Methyl Acrylate Complexed by Zinc Chloride

Abstract

The kinetics of the radical copolymerization of acrylonitrile with methyl acrylate complexed by zinc chloride (ZnCl₂) in dimethylformamide (DMF) was investigated at 60, 65, and 70°C. The kinetic data revealed that R_p was an inverse function of ZnCl₂ concentration and directly related to monomers concentration. The increase in the activation energy from 11.85 to 19.25 kJ·mol^?1 and the decrease in the value of the ratio of the propagation to termination rate constants (k_p ²/k_t ) from 0.08 to 0.06 L·mol^?1·s^?1 on the addition of ZnCl₂ indicated its retarding effect. The chain transfer constant of DMF for the system was 16.25 × 10^?4, accordingly the degree of polymerization decreased. The structure and composition of the copolymers determined by ¹H-NMR and elemental analysis was found to be alternating. The nonideal behavior of the glass transition temperatures determined by DSC also favors the alternation of monomer units in the copolymer. The reaction proceeds via a cross-propagation mechanism.     

辐射引发丙烯腈－丙烯酸甲酯－衣康酸三元沉淀共聚合

辐射引发丙烯腈－丙烯酸甲酯－衣康酸三元沉淀共聚合张志成,葛学武,葛敏,张健（中国科学技术大学应用化学系,合肥,２３００２６）关键词聚丙烯腈,超高分子量,辐射引发,沉淀共聚合制备高性能的碳纤维,首先要制备优良的丙烯腈基原丝（ＳＡＦ）．ＳＡＦ聚合物具有超...     

Suspended Emulsion Copolymerization of Acrylonitrile with Methyl Acrylate: Effects of Reaction Parameters on the Polymerization

Acrylonitrile/methyl acrylate copolymers were synthesized by suspended emulsion polymerization with water as dispersed phase and monomers as continuous phase, potassium peroxydisulphate (KPS) as initiator, Span-80 as emulsifier, and poly(vinyl alcohol) (PVA) as suspending agent. Effects of reaction parameters such as water/monomer mass ratio, concentration of initiator, polymerization temperature and agitation rate on polymerization conversion and the particle size distribution of acrylonitrile/methyl acrylate copolymers were studied. It was found that polymerization conversion increased with an increase of water/monomer mass ratio, concentration of initiator and polymerization temperature, while the agitation rate had no significant effect on the polymerization conversion. Particle size distribution became narrower with an increase of water/monomer mass ratio and agitation rate. Under the same initiator concentration and polymerization temperature, particle size distribution became wider along with polymerization time. The differential scanning calorimetry (DSC) results indicated that the peak temperature of the copolymers decreased with increasing MA content.     

Graft Copolymerization of Monomer Mixtures Acrylonitrile/Ethyl Acrylate and Acrylonitrile/Methyl Methacrylate on Carboxymethyl Cellulose

Abstract

Graft copolymerizations of acrylonitrile/ethyl methacrylate and acrylonitrile/methyl methacrylate monomer mixtures on carboxy methyl cellulose (d.s. 0.4–0.5) were studied in aqueous medium at 30°C using ceric ion as initiator. The amounts of the polymer grafted were measured as a function of the mole fraction of acrylonitrite in the feed. The compositions of the copolymer samples were obtained from their nitrogen contents. It was found that the presence of acrylonitilte in the polymerization system was associated with reductions (of up to 80%) in the amounts of polymer grafted; and that disproportionately low amounts of acrylonitrile monomeric units were incorporated into the graft copolymer even at relatively high acrylonitrile content of the feed.     

Copolymerization and Copolymers of 2,4,5-Tribromostyrene with Methyl Acrylate and Methyl Methacrylate

Abstract

2,4,5-Tribromostyrene (TBSt) was copolymerized with methyl acrylate (MA) or methyl methacrylate (MMA) in a toluene solution using 2,2′-azobisisobutyronitrile as free radical initiator. The copolymerization reactivity ratios were found to be for the system TBSt / MA r₁= 7.4 ± 1.2 (TBSt) and r₂= 0.1 ± 1.4 (MA) and for the system TBSt / MMA r₁ = 1.8 ± 0.2 (TBSt) and r₂ = 0.1 ± 0.2 (MMA). The e and Q values were also calculated. The initial rate of copolymerization, as well as molecular weight of the obtained copolymers for both system linearly increase as the content of TBSt in the monomer mixture increases. Similar behavior has also been established for the course of the copolymerization reactions to high conversions. The resulting copolymers rapidly decompose at temperatures 20–800°C above the decomposition of corresponding (metha)crylate hompolymers. However, the glass transition temperature increases markedly with increasing TBS content.     

The Radiation-Induced Copolymerization of Methyl Methacrylate with Di- and Trimethacrylates

The rates and gel formation of the radiation-induced co-polymerization of a number of dimethacrylates and trimethylol propane trimethacrylate with methyl methacrylate has been studied in detail. The rates were found to be linked to the nature and amount of gel formed rather than to differences in the reactivities of the monomers.     

Copolymers of p-Nitrobenzyl Acrylate with Methyl Acrylate: Synthesis,Characterization, and Monomer Reactivity Ratios

Abstract

Copolymers of p-nitrobenzyl acrylate and methyl acrylate with different feed ratios are synthesized in ethyl methyl ketone using benzoyl peroxide as a free radical initiator at 70 ± 1°C. The copolymers were characterized by IR and ¹H-NMR spectroscopic techniques. Copolymer compositions were determined by ¹H-NMR analysis of the polymers. The monomer reactivity ratios were determined by the application of conventional linearization methods such as Fineman–Ross and Kelen–Tüdös. Gel permeation chromatography was used for determining the molecular weights M _n and M _w, and the polydispersity index. The intrinsic viscosities and the thermal properties of the homo- and copolymers are also discussed.     

Kinetic Investigations of the Copolymerization of Ethyl Acrylate and Acrylonitrile with Maleic Anhydride

The copolymerization of maleic anhydride with ethyl acrylate (I) in 1,2-dichloroethane and with acrylonitrile (II) in acetone at 50°C with AIBN as initiator was investigated. The v _Br curves show no maximum. The v _Br values and molecular weights decrease with the molar fraction xM An. The r values for both pairs of monomers were determined. For I, k _St, k _z, and f were also ascertained and v _Br curves calculated, and they are compared with the experimental results.     

Radiation-Induced Graft Copolymerization of Mixtures of Acrylic Acid and Acrylonitrile onto Cellulose

Graft copolymerization of mixtures of acrylic acid and acrylonitrile (AN) onto irradiated cellulose was studied. The effects of radiation dose, temperature, duration, and concentration of the monomers were investigated. The extent of grafting was found to increase with radiation dose, temperature, and duration. Grafting was higher with increasing AN concentrations.     

Kinetics of Copolymerization. III. Determination of the Rate of Initiation in the Copolymerization System Acrylonitrile/Methyl Acrylate/Dimethylformamide

For the AIBN-initia ted copolymerization System acryionitriie/methyl methacrylate/dimethylformamide, the dependence of the composition of the monomer mixture on the rate constant of initiation and that of the initiator decomposition has been inves-tigated at 313, 323, and 333° K. It was established that the rate constant of initiator decomposition is independent of, while that of the initiation is dependent on, the composition of the monomer mixture. The efficiency of initiation has been calculated and its value was found to be somewhat altered not only by the composition of the monomer mixture but also decreased siightiy with an increase of temperature.     

丙烯酸甲酯和甲基丙烯酸酯基团转移无规共聚的竞聚率

丙烯酸甲酯和甲基丙烯酸酯基团转移无规共聚的竞聚率⒇邹友思林东海张景辉潘容华（厦门大学化工系，厦门大学核磁共振实验室，厦门，３６１００５）单体竞聚率作为一个定量数据，对于不同投料比下共聚物组成的预计和控制，共聚反应动力学和机理研究均有重要作用。丙烯酸...     

Anionic Copolymerization of Acrylonitrile with Methyl Acrylate under the Action of a Novel Initiating System Based on a Bicyclic Tertiary Amine and Ethylene Oxide

Russian Journal of Applied Chemistry - Anionic copolymerization of acrylonitrile with methyl acrylate under the action of the 1,4-diazabicyclo[2.2.2]octane–ethylene oxide initiating system...     

新型苯并咪唑取代的丙烯腈及丙烯酸酯衍生物的催化合成

从邻苯二胺出发,合成了2-氰甲基苯并咪唑,在优选出的催化剂吗啡啉/乙酸催化下,合成了新型的双苯并咪唑丙烯腈衍生物和3-吲哚-2-苯并咪唑丙烯腈衍生物;将2-氰甲基苯并咪唑经过碱性水解、酯化,得到苯并咪唑乙酸乙酯,后者经过Knoevenagel缩合/分子内酯交换接续反应高产率地得到了新型的苯并咪唑取代的香豆素衍生物。     

氨酯丙烯酸酯树脂的合成及其固化反应动力学研究

用不同分子量的聚氧化丙烯二元醇合成了一系列氨酯丙烯酸酯齐聚物（ＵＡＯ）以及含硬段／软段结构的ＵＡＯ，并用ＦＴ－ＩＲ跟踪了这类ＵＡＯ的合成过程。通过ＵＡＯ的链端双键测定，以及ＧＰＣ、ＶＰＯ测定的分子量，表征了ＵＡＯ的数均官能团度。进一步通过ＦＴ－ＩＲ研究了由ＵＡＯ与甲基丙烯酸甲酯形成的氨酯丙烯酸酯树脂（ＵＡＲ）固化时的共聚反应动力学，发现其共聚反应速率与体系中的扩散效应密切相关。在这类ＵＡＯ中引入硬段后，共聚合体系呈现出反常的动力学行为，与网络结构形成过程中材料的形态发展有关。     

Reactive Surfactant in the Emulsion Copolymerization of Methyl Methacrylate and Octyl Acrylate

The emulsion copolymerization of methyl methacrylate and octyl acrylate was studied using a reactive surfactant ammonium sulfate allyloxy nonylphenoxy poly(ethyleneoxy) (10) ether (DNS‐86), and a conventional surfactant sodium dodecylbenzene sulfonate (DBS) with a similar structure as a comparison sample. A series of latex samples have been prepared with two kinds of surfactants, and their properties have been characterized and compared. ¹H‐NMR proves that the reactive surfactant has been incorporated into the resulting copolymers. The atomic force microscopy (AFM) proves that the reactive surfactant DNS‐86 migrate to the surface of the latex film to a much less degree than the conventional surfactant DBS. Transmission electron microscopy (TEM) demonstrates that there are some differences in the particle morphologies. The stability and water‐resistance of the latex films prepared by reactive surfactant DNS‐86 are better than those prepared by the conventional surfactant DBS.     

Copolymerization of Acrylonitrile with Functional Silanes

Acrylonitrile (AN) has been copolymerized with vinyltriethoxy-silane (VTES) and vinyltris(methoxy ethoxy)silane (VTMES) in bulk at 60°C using benzoyl peroxide. The copolymer composition has been determined from elemental analysis. The reactivity ratios of AN (MI) copolymerizations with VTES (r₁ = 4.72, r₂ = 0) and VTMES (r₁ = 2.45, r₂ = 0) have been determined. Mechanistic explanations of the monomer reactivities are presented. The structure-property relationship of AN-vinylsilane copolymers has been discussed.     

丙烯腈在聚丙烯上接枝共聚

丙烯腈在聚丙烯上非均相接枝共聚，得杨梅形氰基树脂。研究了接枝共聚条件对单体转化率和接枝率的影响。表观聚合速度可表示为，碰撞频率因子和聚合活化能分别是1．36×1011s-1和99．2kJ．mol-1。从光学显微镜观察到改性树脂在水中接枝连束的分布状态。丙烯腈和二乙烯基苯在聚丙烯上接校共聚，再经二甲苯率取，得笼形氰基树脂。二乙烯基苯在单体中的相对含量对树脂的溶胀性能和笼孔尺寸有很大的影响，制取功能材料时应予适当调节。扫描电镜照片展示了笼形树脂的笼腔和网络结构形态。     

Radiation-Induced Copolymerization of Chlorotrifluoroethylene with Olefins

The copolymerizations of chlorotrifluoroethylene with propylene and isobutylene were carried out at 0 ～ ?78°C by γ-ray irradiation. It was found that alternating copolymers are obtained over a wide range of monomer composition for both systems. The alternating copolymer of chlorotrifluoroethylene with isobutylene was found to be highly crystalline, but the copolymer of chlorotrifluoroethylene with propylene was found to be amorphous. The copolymerizations were considered to proceed via a radical mechanism, but in the case of the isobutylene-chlorotrifluoroethylene system a cationic polymerization also takes place simultaneously at ?78°C.     

2-甲基-7-亚甲基-1,4,6-三氧螺[4,4]壬烷与丙烯腈、丙烯酸甲酯的共聚合反应及竞聚率的测定

用高效液相色谱跟踪2-甲基-7-亚甲基-1,4,6-三氧螺[4,4]壬烷(MMTN)与丙烯腈(AN),丙烯酸甲酯(MA)的共聚合反应。根据Lowry-Meyer共聚积分方程式,采用插值法进行数据拟合测定单体的竞聚率。对于体系MMTN(M_1)-AN(M_2),r_1=0.048;r_2=0.213;MMTN(M_1)-MA(M_2)r_1=0.025,r_2=0.764。说明两组共聚体系均有较强的交替共聚趋势。