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1.
The free-radical-induced reactions of cyclohexene oxide in the presence of maleic anhydride have been found to lead to polyether in presence of AIBN and to a mixture of polyether, ester, and maleic anhydride adduct of polyether with di-tert-butyl peroxide (DTBP), the amounts of the mixture components depending on the concentration of DTBP and the temperature. Analogous reactions in the presence of succinic anhydride lead to no polyether. The obtained polyether has no hydroxyl group. The reaction appears to consist of three different steps, radical initiation, cationic propagation, and radical termination. 相似文献
2.
R. K. Sadhir J. D. B. Smith P. M. Castle 《Journal of polymer science. Part A, Polymer chemistry》1983,21(5):1315-1329
Laser-initiated polymerization of charge transfer monomer complexes has been investigated using an argon ion laser. The influence of solvents, monomer feed ratio, and irradiation time on the copolymer yield and composition was evaluated. The polymer yield was found to be directly proportional to the irradiation time and the molar concentration of maleic anhydride in the monomer feed. An enhanced rate of polymerization was obtained by substituting electron donating groups in the donor monomer. Polymerization, initiation, and propagation mechanisms, via charge transfer complexes, have been discussed. Comparison of laser-induced polymerization with UV-induced polymerization suggests that laser initiation is an energy-efficient process. 相似文献
3.
Isao Nagahiro Koji Nishihara Naokazu Sakota 《Journal of polymer science. Part A, Polymer chemistry》1974,12(4):785-792
Maleic anhydride (MAn) was irradiated with ultraviolet light in dioxane at 35°C without initiator, and predominantly a MAn oligomer was obtained with a small quantity of cyclic dimer of MAn. Mass spectrometric, NMR, and elementary analysis investigation of the oligomer showed that it is composed of about four MAn units and one dioxane molecule per molecule. 相似文献
4.
Maleic anhydride (MAH) was photografted onto low density polyethylene substrates at temperatures above the melting point of MAH. The effects of some principal factors including irradiation temperature, photoinitiators, the intensity of UV radiation, and the far UV radiation on the grafting polymerization were investigated in detail. Percent conversion and grafting efficiency of the polymerizations were determined by the gravimetric method. The contact angles of the grafted film PE-g-PMAH against water and the FTIR spectrum of the grafted film were measured as characterization. The results show that the photografting polymerization of MAH can proceed smoothly at temperatures higher than the melting point of MAH; the far UV radiation and the intensity of the UV radiation affect the grafting polymerization greatly; the photoinitiators also have influence on the polymerization. According to the FTIR spectra, it is clearly confirmed that the grafted film samples contain anhydride groups. The contact angles demonstrate that the wettability of the grafted films is enhanced obviously, especially to those grafted film samples through hydrolysis. 相似文献
5.
Koichi Takakura Koichiro Hayashi Seizo Okamura 《Journal of polymer science. Part A, Polymer chemistry》1966,4(7):1747-1757
In order to elucidate the reaction mechanism of both the radiation-induced and benzoyl peroxide-catalyzed polymerizations of cyclic ethers in the presence of maleic anhydride, the development of color during reaction and copolymerization of oxetane derivatives were investigated. Upon addition of a small amount of the γ-ray or ultraviolet-irradiated equimolar solution of a cyclic ether and maleic anhydride to isobutyl vinyl ether, a rapid polymerization took place, and the resulting polymer was confirmed to be a homopolymer of isobutyl vinyl ether. A heated solution of dioxane, maleic anhydride, and a small amount of benzoyl peroxide can initiate the polymerization of isobutyl vinyl ether in the same manner. The electrical conductivity of a 1:1 mixture of maleic anhydride and dioxane is increased by about a factor of ten after ultraviolet irradiation. These results indicate that some cationic species are actually formed in the system by irradiation or the decomposition of added benzoyl peroxide. The mechanism of formation of the cationic species responsible for the initiation may be explained as follows. A free radical of an ether is formed by abstraction of a hydrogen atom attached to the carbon adjacent to oxygen atom, followed by a one-electron transfer from the resulting radical to maleic anhydride, an electron acceptor, to yield the cationic species of the ether and the anion-radical of maleic anhydride, respectively. The resulting cationic species as well as the counteranion-radical are resonance-stabilized. Therefore, the present polymerization may be designated a radical-induced cationic polymerization. 相似文献
6.
Ural Akbulut Bilge Haciolu 《Journal of polymer science. Part A, Polymer chemistry》1991,29(2):219-224
Controlled potential electrolysis was employed to accomplish homopolymerization of maleic anhydride, by direct electron transfer. The solvent used in the polymerization studies was acetonitrile–dimethylformamide mixture (1 : 1) with the supporting electrolyte tetrabutylammonium tetra fluroborate, A brown paramagnetic polymer was obtained from the catholyte, upon electroreduction of monomer. 相似文献
7.
Norman G. Gaylord Rajendra Mehta 《Journal of polymer science. Part A, Polymer chemistry》1988,26(7):1903-1909
Polar organic compounds either (1) inhibit the peroxide-catalyzed bulk homopolymerizations of both MAH and MMA at 80°C, (2) do not inhibit the polymerization of either MAH or MMA, or (3) inhibit the polymerization of MAH but not that of MMA. Compounds generally used as polymerization inhibitors or antioxidants inhibit the polymerizations of both MAH and MMA, presumably by interaction with peroxide decomposition products. Ketones, ethers, acids, esters, nitriles, imides, sulfones, sulfonates, sulfonamides, and acyl disulfides do not inhibit either MAH or MMA polymerization. However, amides, lactams, carbamates, amine oxides, phosphites, phosphates, phosphonates, phosphoramides, phosphine oxides, monosulfides, sulfoxides, aryl disulfides, and thiazyl disulfides inhibit the polymerization of MAH but not that of MMA. Inhibition presumably occurs as a result of electron transfer from the nitrogen-, phosphorous- or sulfur-containing electron donor compound to the MAH carbocation which is an intermediate in the polymerization of MAH. 相似文献
8.
M. A. Williamson J. D. B. Smith P. M. Castle R. N. Kauffman 《Journal of polymer science. Part A, Polymer chemistry》1982,20(7):1875-1884
The laser-initiated polymerization of charge-transfer monomer complexes was investigated with a pulsed nitrogen laser and an argon laser. Several donor-acceptor monomer charge-transfer systems were screened for polymerization in different solvents. Polymerization by laser initiation was achieved in two of these systems; that is, 2-vinylnaphthalene/fumaronitrile and 9-vinylanthracene/fumaronitrile. The best polymer yields were obtained with the 2-vinylnaphthalene/fumaronitrile system in sulfolane solvent. The influences on the polymer yield and composition of solvents, varying focal path length, glass conditioning, initiation sources, environment, and monomer feed ratios were evaluated. Infrared (IR) spectral studies, gel permeation chromatography (GPC), and chemical analyses were performed to characterize the polymer products arising from the polymerization of 2-vinylnaphthalene/fumaronitrile in sulfolane. The polymer contained a high percentage of sulfolane (ca. 1/3 mol fraction), presumably arising from solvent transfer to the growing polymer chains during the propagation phase of the polymerization. 相似文献
9.
The kinetics of the reaction of maleic anhydride with liquid polybutadienes of various microstructures was studied by using
differential scanning calorimetry (DSC). The kinetic results of thermal maleinization show a dependence from m.w. and polybutadiene microstructure. The introduction of a gel inhibitor as copper naphthenate has proved that crosslinking
reactions also occur during the maleinization. On the other hand, the maleinization in the presence of a radical initiator
as dicumyl peroxide (DCP) shows thermal effects higher than pure thermal reaction with a partial overlap of the calorimetric
peaks due to maleinization and crosslinking.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.
The photopolymerization of maleic anhydride (Manh) was carried out in the presence of 2,4,8,10-tetraoxaspiro[5,5]undecane (TU) at 40 in vacuo without initiator to give the hygroscopic oligomer of Manh having a TU unit as each of the end-groups and a small amount of the cyclic dimer of Manh. The initiation mechanism for this oligomerization was discussed. 相似文献
11.
Judit Szalay Istvn Nagy Istvn Bnyai Gyrgy Dek Gyrgy Bazsa Mikls Zsuga 《Macromolecular rapid communications》1999,20(6):315-318
The synthesis of poly(styrene‐maleic anhydride) copolymers by frontal polymerization is reported. The propagating front can be achieved if the mole fraction of styrene (St) is 0.3 ≤ St ≤ 0.7 in the feed. Depending on the St/MA mole ratio alternating St‐MA‐St‐MA copolymers (St/MA ≤ 1) or (St‐MA)n‐(St‐St‐St)m block copolymers (St/MA > 1) are formed. The microstructure of the copolymers obtained was estimated by means of 13C NMR spectroscopy. 相似文献
12.
Randy S. Frank Jeffrey S. Downey H. D. H. Stver 《Journal of polymer science. Part A, Polymer chemistry》1998,36(13):2223-2227
Narrow disperse micron-range divinylbenzene-maleic anhydride microspheres have been prepared in near quantitative yields using precipitation polymerization. A variety of solvents were investigated for use as the reaction medium with a 40:60 mixture of methyl ethyl ketone and heptane providing the best results. The effects of solvent composition on particle size and morphology and monomer loading effects were also investigated. Particle size decreased with increasing solvency (increasing MEK fraction) while increases in monomer loading caused larger particle sizes. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2223–2227, 1998 相似文献
13.
Pinyo Wongthong Charoen Nakason Qinmin Pan Garry L. Rempel Suda Kiatkamjornwong 《European Polymer Journal》2013
Modification of natural rubber (NR) via grafting polymerization with maleic anhydride (MA) has received wide attention as it could improve the hydrophilicity of NR and extend its application to a wider application field. However, the grafting efficiency of MA onto NR in either the molten state or solution state is low and is accompanied with undesired high gel content in the grafts. In this work a novel technical route was developed in that a deproteinization operation was conducted before carrying out the grafting process and a differential microemulsion polymerization technique was applied for the grafting reaction. The effects of initiator and monomer concentration, reaction temperature, and reaction time on the grafting efficiency and gel fraction were investigated, and a comparison of the reaction performance was conducted for deproteinized NR (DPNR) and NR. The results indicated that the deproteinization operation could significantly improve the grafting efficiency and reduce the gel content, and a 29% yield of MA grafted onto the rubber backbone could be achieved at a condition of a DPNR:MA:initiator ratio of 85:9:6 (wt%) at 60 °C for 8 h. 相似文献
14.
A procedure is developed for the determination of maleic anhydride in the presence of endic anhydride by potentiometric titration
in aqueous-organic solutions. It is found that separate titration of a hydrolyzed mixture of anhydrides is most efficient
in the system acetonitrile-water (3 : 2). 相似文献
15.
Jian‐Ping Deng Wan‐Tai Yang 《Journal of polymer science. Part A, Polymer chemistry》2001,39(19):3246-3249
Maleic anhydride (MAH) was photografted onto low‐density polyethylene (LDPE) films with a grafting efficiency of about 70% in the absence of a photoinitiator. The self‐initiating performance was attributed to a mechanism of abstracting hydrogen atoms from LDPE chains by excited MAH dimers. The supporting experimental results were as follows: (1) the far‐UV radiation (200–300 nm) was indispensable for the graft polymerization and 2) the crosslinking reaction of LDPE inevitably accompanied the grafting of MAH. In addition, the initiation performance of MAH was further confirmed by surface photografting of acrylic acid in the presence of MAH, where MAH was used as the photoinitiator. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3246–3249, 2001 相似文献
16.
17.
Norman G. Gaylord Rajendra Mehta 《Journal of polymer science. Part A, Polymer chemistry》1988,26(4):1189-1198
The crosslinking of LDPE resulting from reaction with dicumyl peroxide at 180°C is increased in the presence of maleic anhydride (MAH). The presence of electron-donating nitrogen-containing compounds (amides, lactams, disubstituted aromatic amines, and amine oxides), phosphorous-containing compounds (phosphites, phosphates, phosphonates, phosphoramides, and phosphine oxides) and sulfur-containing compounds (sulfoxides, aryl disulfides, and thiazyl disulfides) which inhibit the homopolymerization of MAH but not that of methyl methacrylate, prevents crosslinking and yields soluble PE containing MAH units. Crosslinking, due to coupling of PE˙ macroradicals formed by hydrogen abstraction from PE by excited MAH, is prevented by electron donation from the additive to the MAH+ cation which is present in the MAH+?MAH excimer as well as in the excimer which is appended to the PE. 相似文献
18.
Ronghua Zhang Yutian Zhu Jianguo Zhang Wei Jiang Jinghua Yin 《Journal of polymer science. Part A, Polymer chemistry》2005,43(22):5529-5534
A series of 13C‐enriched maleic anhydride grafted isotactic polypropylene samples were prepared in solution at 170 °C by changes in the initial maleic anhydride content. The NMR spectra of the samples showed that the signals of the maleic anhydride attached to the tertiary carbons of the isotactic polypropylene chains increased considerably with increasing maleic anhydride content, whereas the signals of the maleic anhydride on the radical chain ends (with a single bond) arising from β scission did not. On the other hand, the signals of the maleic anhydride on the radical chain ends with double bonds increased markedly with increasing maleic anhydride content, and this suggested that β scission could occur extensively after maleic anhydride was attached to the tertiary carbons. As a result, the molecular weight of the grafted polypropylene decreased significantly with increasing maleic anhydride content in this study. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5529–5534, 2005 相似文献
19.
《Journal of Molecular Catalysis #》1991,64(3):277-282
Under the activation of pulsed UV laser, a highly efficient catalyst was formed from W(CO)6-CCl4. The polystyrene obtained was characterized by IR spectroscopy and its molecular weight was measured to be 2.5 × 104. The influences of irradiation time, polymerization time and catalyst lifetime were studied. Comparisons of catalysts from W(CO)6-CCl4, Mo(CO)6-CCl4 and Cr(CO)6-CCl4 are made. The comparison between catalytic polymerizations of phenylacetylene and of styrene is also discussed. 相似文献
20.
用AM1方法计算了马来酸酐、羟基自由基及其加成产物α-羟基丁二酸酐基自由基的电子结构、电荷分布和键级.应用前线轨道理论和成键三原则研究了羟基自由基引发下马来酸酐聚合过程中α-羟基丁二酸酐基自由基活性中间体参与反应的可能性及其自由基聚合反应机理.计算结果表明:马来酸酐基态分子的HOMO和LUMO分别对应于双键CC的成键π-MO和反键π -MO;马来酸酐的羟基自由基加成反应活化能计算值为55 7kJ/mol;马来酸酐在羟基自由基引发下的自由基聚合产物是链式结构,与实验事实相符. 相似文献