Donor-Acceptor Complexes in Copolymerization. LIX. Alternating Diene-Dienophile Copolymers. 13. Copolymerization of Dicyclopentadiene and Maleic Anhydride

The solution and bulk copolymerization of dicyclopentadiene (DCP) and maleic anhydride (MAH) occurs over the temperature range 80–240°C, upon the addition of a free-radical catalyst which has a short half-life at the reaction temperature. An unsaturated 1/1 MAH/DCP copolymer, derived from the copolymerization of MAH with the norbornene double bond, followed by a Wagner-Meerwein rearrangement, is obtained in the presence of a large excess of DCP at 80° C, while a saturated 2/1 MAH/ DCP copolymer, derived from the cyclocopolymerization of the residual cyclopentene unsaturation, is obtained at higher temperatures or in the presence of excess MAH. The copolymers prepared under other conditions with intermediate MAH/DCP mole ratios contain both 1/1 and 2/1 repeating units. The copolymer obtained from bulk copolymerization above 170° C contains units derived from cyclopentadiene-MAH cyclocopolymerization as well as DCP-MAH copolymerization.     

Donor-Acceptor Complexes in Copolymerization. III. Conjugated Diene-Acrylonitrile Copolymerization in the Presence of Metal Halides

The copolymerization of isoprene or butadiene with acrylonitrile in the presence of zinc chloride or ethylaluminum sesquichloride, in the presence or absence of a free radical catalyst, at 30-70°C yields an equimolar, diene-acrylonitrile alternating copolymer containing more than 90% trans-1,4 unsaturation, irrespective of monomer charge. The copolymer results from the homopolymerization of a diene-acrylonitrile…metal halide transoid charge transfer complex. When ZnCl₂ is the electron-accepting metal halide and the polymerization is carried out at temperatures of 50°C and higher or to high conversions, the equimolar copolymer is accompanied by a high acrylonitrile polymer, and in the presence of a radical catalyst, by a normal radical copolymer. In the presence of the organoaluminum halide and in the absence of a radical catalyst, the alternating copolymer is the only product, irrespective of monomer charge. However, in the presence of a radical catalyst and at high acrylonitrile monomer charges, e.g., D/AN = 10/90, the alternating copolymer is accompanied by a normal radical copolymer. The formation of equimolar, alternating copolymer at all monomer ratios and in the absence or presence of a radical catalyst indicates that the (D-AN…MX) charge transfer complex readily undergoes homopolymerization and does not copolymerize with free diene or acrylonitrile or with the AN-AN…MX complex.     

Donor-Acceptor Complexes in Copolymerization. LXIII. Alternating Diene-Dienophile Copolymers. 15. Copolymerization of Cyclopentadiene and the Isomeric N-Phenyl-5-norbornene-2,3-dlcarboximides with N-Phenylmaleimide

Abstract

The copolymerization of cyclopentadiene (CPD) and N-phenyl-maleimide (NPMI) at 80–195°C, in the presence of a radical catalyst having a short half-life at the reaction temperature and less than 25% solvent, yields a 1:2 CPD-NPMI copolymer (DP 2–3) which is identical (IR, NMR) to the endo 1:1 copolymer (DP 18) obtained under the same conditions from the copolymerization of the endo CPD-NPMI Diels-Alder adduct and NPMI. The exo CPD-NPMI adduct copolymerizes with NPMI under the same conditions to yield an exo 1:1 copolymer (DP 8). Under the same conditions the homopolymerization of the endo and exo CPD-NPMI adducts is effected in the melt at temperatures up to 260°C and in solution at 120–155°C. The homopolymers (DP 3–7) prepared below 210°C retain the configuration of the adducts while the homopolymers prepared at 260°C from either isomer contain both endo and exo configurations due to isomerization. The participation of excited species is suggested by the requirement for high-speed decomposition of radical catalysts to effect homopolymerization and copolymerizations.     

Donor-Acceptor Complexes in Copolymerization. XXXVI. Alternating Diene-Dienophile Copolymers. 4. Copolymerization of Furan and 2-Methylfuran with Maleic Anhydride

Abstract

The copolymerization of furan and 2-methylfuran with maleic anhydride in the presence of a radical catalyst yields equimolar, alternating copolymers in which the furan units have a 2,5-linkage (NMR and IR). The copolymerization appears to have a floor temperature of about 40°C. The furan-maleic anhydride Diels-Alder adduct polymerizes in solution in the presence of a radical catalyst at temperatures above 60°C to yield the identical copolymer as is obtained from the monomers. The adduct undergoes a retrograde reaction above 60°C to regenerate the monomers which then copolymerize through excitation of the ground state comonomer charge transfer complex.     

Ultrasonic Degradation and Copolymerization of Poly (Vinyl Alcohol) with Acrylonitrile

The ultrasonic degradation of poly(vinyl alcohol) (PVA) in aqueous solution and copolymerization of PVA with acrylonitrile (AN) were studied. It is confirmed that the rate of degradation of PVA follows the kinetic equation suggested by Baramboim. Both water-soluble and water-insoluble copolymer can be obtained by changing the irradiation time or the amount of AN added to the aqueous solution of PVA. The structure of the copolymer was identified by IR, MS, PGC, and x-ray diffraction. The copolymer prepared is mainly a block one. By irradiating 2% PVA/AN (1/1.6, w/w) at 20 ± 1°C and 21. 5 kHz with 490 W for 28 min, the yield of water-soluble copolymer is 25.49%, the AN content in which is 13.98%. After 100 min, with the weight ratio between PVA and AN 1/4, the yield of the water-insoluble copolymer amounted to 296.01%, the AN content in which is 75.56%.     

Quasiliving Carbocationic Polymerization. XII. Forced Ideal Copolymerization of lsobutylene with Styrene

Forced ideal carbocationic copolymerization of isobutylene/styrene systems has been achieved by continuous addition of mixed monomer feeds to 2-chloro-2,4,4-trimethylpentane/TiCl₄ in n-hexane/methylene chloride charge by keeping the input rate equal to the overall rate of copolymerization. The composition of the copolymers was identical to that of the feeds over the entire monomer concentration range. The number-average molecular weight of the copolymers increased almost linearly with the amount of consumed monomers at higher isobutylene concentrations in the feed. The molecular weight increase was less pronounced at higher styrene concentration because more methylene chloride had to be used in the solvent system to keep the copolymer in solution. The micro-structure of the copolymers is uniform as determined by gel permeation chromatography (UV plus RI) and ¹³C-NMR spectroscopy According to these studies, true copolymers have formed. The probability of triads in the copolymer has been determined.     

Copolymerization of styrene and diethyl fumarate with zinc bromide. III. Electroinitiation at low current densities

The electroinitiated preparation of equimolar copolymers of styrene and diethyl fumarate is described. The reaction medium consisted of these monomers dissolved in a methanol–zinc bromide solution. Rates of polymerization increased with increasing applied current and the copolymer yield increased linearly with the total number of Faradays transferred. The copolymer composition is 1:1 and is essentially invariant with the degree of conversion (<15%), electroinitiation rate, and monomer feed ratios. A reaction mechanism involving donor–acceptor complexes and electroinitiated excitation of these complexes at the electrode is postulated.     

超声辐照下PEO与NaMAA嵌段共聚反应的研究

本文研究了在超声波辐照下聚氧化乙烯与甲基丙烯酸钠在水溶液中的嵌段共聚反应和共聚物结构。共聚反应按自由基聚合机理进行。反应动力学方程可用-(d[M]/(dt))=k[R·]^(1/6)[M]表示。随辐照时间或单体浓度的增加,共聚物产率和共聚物中NaMAA含量增大。将1％PEO-105％NaMAA水溶液在频率21.5kHz、阴极电流0.7A的超声强度下辐照15分钟,共聚物的产率为24.0％。用IR、MS、NMR、DSC、TEM等分析了共聚物的化学结构和聚集态结构,表明所得共聚产物为嵌段共聚物。     

Studies on Ultrasonic Degradation and Block Copolymerization of Hydroxyethylcellulose and Poly(ethylene Oxide)

The ultrasonic degradation of hydroxyethylcellulose (HEC) and poly (ethylene oxide) (PEO) in aqueous solution, and the copolymerization of HEC with PEO were studied. The structure of the copolymer was identified by DTA, IR, MS, x-ray diffraction, and polarizing microscopy. The copolymer prepared is mainly block. The copolymer formed amounts to 55.07% by irradiating 0.5% HEC/PEO aqueous solution for a period of 10 min at 25°C and 18.2 kHz with 2.5 A input current on a reversed main circuit.     

Radiation-Induced Copolymerization of Thiophene with Maleic Anhydride

Radiation-induced copolymerization of thiophene with maleic anhydride has been studied. On the copolymerization in chloroform solution, the effects of dose rate, polymerization temperature, and, monomer composition and concentration on the yield and molecular weight of the copolymer were determined. The copolymerization proceeds via a radical mechanism with bimolecular termination of propagating polymer radicals, and the apparent activation energy is 5.3 kcal/mole. By NMR spectroscopy of copolymer, it was also found that these monomers copolymerize alternately to give a copolymer having structure I. In this copolymerization, the higher initial rates were obtained at an equimolar composition of monomers and by using solvents containing chlorine, such as CC1₄, CHC1₃, and C₆H₅C1.     

苯酚苯胺共聚物在304不锈钢电极表面的电化学合成及成膜微观结构分析

Electrochemical copolymerization of phenol and aniline was achieved on 304 stainless steel anodes in neutral water solution with an electrolyte of Na₂SO₄O₄. Compared with pit corro-sion potential of different copolymer coatings, the best solution composition was 0.09 mol/L phenol and 0.01 mol/L aniline. Through infrared spectrum analysis, polyaniline structure was proved in phenol-aniline copolymer, as well as more side chains. Scanning electron mi-croscope was used to analyze microstructure of copolymer coating, taking advantage of part solubility of phenol-aniline copolymer in tetrahydrofuran, the bifurcate network structure was observed. The copolymer coating microstructure was summarized, compared with the performance of polyphenol coatings, the reasons of corrosion resistance enhancement with the addition of aniline in electropolymerization reaction was assumed as well.     

C60-苯乙烯-顺丁烯二酸酐的三元自由基共聚

自从研制出克量的Ｃ6 0 [1],其在超导光、电、磁、生物等领域的研究迅速发展 .由于Ｃ6 0 只溶于几种非极性溶剂中 ,其使用受到限制 ,从而制备Ｃ6 0 的高分子衍生物一直被认为是Ｃ6 0 材料化的重要途径[2 6 ].文献 [39]报道 ,富勒烯与含双键的单体如苯乙烯、甲基丙烯酸甲酯等可很方便地进行自由基共聚 ,得到富勒烯与烯类单体的共聚物 ,产物可溶于四氢呋喃等有机溶剂 .但迄今为止 ,可溶于水或其它强极性溶剂中的Ｃ6 0 聚合物研究的很少[10 ,11],而Ｃ6 0 的三元共聚物的制备几乎未见报道 ,为此 ,我们采用自由基共聚制备了Ｃ6 0 苯乙烯 顺丁烯…     

Photoinduced Graft Copolymerization onto Chitosan Under Heterogeneous Conditions

Photoinitiated graft copolymerization of acrylamide onto chitosan under heterogeneous conditions and in the absence of a photo initiator was investigated. The effect of irradiation time, the amount of chitosan and monomer concentration on the extent of grafting was examined. The maximum grafting percentage obtained was 294%. The copolymer was characterized using carbon-13 nuclear magnetic resonance (¹³C-NMR) spectroscopy, X-ray diffraction analysis (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The system designed allows synthesis of grafted chitosan with free amine groups which are otherwise possible only by chemical protection. The swelling properties of copolymer were followed in aqueous solution.     

以PAAS为模板AM与DMC的模板共聚合反应

在水溶液中以聚丙烯酸钠(PAAS)为模板,进行了丙烯酰胺(AM)与2-甲基丙烯酰氧乙基三甲基氯化铵(DMC)的共聚合反应。研究了其聚合动力学,并对模板共聚物的序列结构进行了表征,最后对其进行了絮凝性能评价。结果表明:聚合反应符合模板聚合Ⅰ型机理,聚合反应速率分别与单体浓度和引发剂浓度的1.63和1.64次方成正比,此种共聚物与无模板参与聚合的普通共聚物相比具有更长的DMC序列长度,对高岭土悬浮液的絮凝沉降速率优于普通共聚物。     

Copolymerization of N-Vinylcarbazole with 2-Dimethylaminoethyl Methacrylate

The thermal copolymerization of N-vinylcarbazole (VCz) with 2-dimethylaminoethyl methacrylate (DMAEM) initiated by α,α′-azobisisobutyronitrile (AIBN) in solution in tetrahydrofuran at 60°C has been studied. Different compositions of copolymer were prepared and characterized by UV, IR, and ¹H-NMR spectroscopy, viscosity measurements, and thermal studies. The estimation of the composition of VCz and DMAEM in the copolymer was carried out by UV spectroscopy. The reactivity ratio of VCz (r ₁) and DMAEM (r ₂) was determined by the methods of Mayo and Lewis, Kelen and Tüdös, and Tidwell and Mortimer.     

甲基丙烯酸缩水甘油酯与甲基丙烯酸甲酯的共聚合及竞聚率测定

以N,N-二甲基甲酰胺(DMF)为溶剂,实施了甲基丙烯酸缩水甘油酯(GMA)与甲基丙烯酸甲酯(MMA)的溶液共聚合,测定了共聚物P(GMA-co-MMA)的红外光谱(FT-IR),对其化学结构进行了表征,并采用差示扫描量热法(DSC)测定了共聚物的玻璃化转变温度(Tg).改变两单体投料比进行共聚合,采用化学分析法测定低转化率下(<7%)共聚物组成,重点研究了两单体的竞聚率.结果表明:GMA与MMA的共聚合易于进行,P(GMA-co-MMA)的玻璃化转变温度(Tg)介于均聚物PGMA(72℃)与PMMA(106℃)之间,当n(GMA)/n(MMA)=4/6时,共聚物的Tg为9l℃.采用FR和KT 2种作图法及YBR计算法对单体的竞聚率进行了计算和比较,结果表明:KT和YBR法较为准确,以DMF为溶剂时,GMA与MMA的竞聚率分别为2.14与0.69.     

Thermodynamic Theory of Equilibrium Copolymerization

General equations are derived for the thermodynamics of equilibrium copolymerization based on the diad model of copolymer. Physical interactions between components in solution are taken into consideration. Several special cases are treated in detail. When these physical interactions are absent, the relations obtained from the theory agree completely with those derived from the kinetics. Equilibrium monomer concentrations are illustrated as functions of excess free energy due to formation of heterodiad, equilibrium constants of homopolymerization, and initial monomer concentrations. It is shown that when the physical interactions are present, their effects cannot be ignored even in dilute solution. In bulk copolymerization, the physical interactions have a considerable effect on equilibrium, especially when the equilibrium monomer volume fractions are relatively small.     

Copolymerization of acrylonitrile. I. Copolymerization with styrene derivatives containing nitrile groups in the side chain

Acrylonitrile was copolymerized in bulk with cinnamonitrile (I), ethyl benzylidenecyanoacetate (II), and benzylidenemalononitrile (III) by radical initiation up to low conversions. The conventional scheme of copolymerization fitted all the three copolymer pairs.     

Copolymerization of Vinyl Chloride and Sulfur Dioxide. II. Copolymerization Rates and Copolymer Compositions

The rate of copolymerization of vinyl chloride (VC) with sulfur dioxide and the composition of the poly (vinyl chloride sulfone) formed have been measured for comonomer liquid mixtures with X_VC = 0.1 to 1.0 and over the temperature range -95 to +46°C.

Polymerization was initiated by γ-irradiation (-95 to +46°C) and with the t-butyl hydroperoxide/SO₂/methanol redox system (-95 to -18°C). The copolymerization rates and copolymer compositions indicated two distinct temperature regions, with a change in mechanism around 0°C. For radiation initiation below 0°C, the rate versus comonomer composition relationship showed a maximum at an x_VC value which increased with increasing temperature. Above 0°C, the rate decreased with increasing temperature and was greatly retarded by SO₂. No high molecular weight copolymer or VC homopolymer was formed on irradiation of comonomer mixtures above ～55°C.     

Reactivity Ratios of Butyl Acrylates in Radical Copolymerization with Methacrylates

The reactivity ratios of four butyl acrylates versus methyl methacrylate and tert-butyl methacrylate were determined for their radical copolymerization in 2-butanone solution using the Jaacks method. The reactivity ratios values obtained were positively verified by substituting into the Alfrey-Goldfinger equation, yielding correct copolymer composition for a series of samples obtained from different initial mole fractions of the comonomers.