Laser-initiated copolymerization of maleic anhydride with styrene,vinyltoluene, and t-butylstyrene

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.     

Free-radical-induced polymerization of epoxides in the presence of maleic anhydride

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.     

Polymerization of cyclic ethers in the presence of maleic anhydride. Part II. Investigation of the polymerization mechanism

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.     

Laser-Initiated copolymerization of N-vinylpyrrolidone with maleic anhydride and maleimide

This article describes the laser-initiated copolymerization of N-vinylpyrrolidone with maleic anhydride and maleimide via charge transfer complexes. The dependence of copolymer yield on the molar ratios of the monomers in the feed and on the irradiation time is described. Based on the ultraviolet and infrared spectroscopy, and chemical analysis results, a tentative mechanism of polymerization is suggested. The rates of polymerization of several monomer systems are compared. The N-vinylpyrrolidone and maleimide system shows the highest rate of polymerization.     

Transparent Films from CO2‐Based Polyunsaturated Poly(ether carbonate)s: A Novel Synthesis Strategy and Fast Curing

Transparent films were prepared by cross‐linking polyunsaturated poly(ether carbonate)s obtained by the multicomponent polymerization of CO₂, propylene oxide, maleic anhydride, and allyl glycidyl ether. Poly(ether carbonate)s with ABXBA multiblock structures were obtained by sequential addition of mixtures of propylene oxide/maleic anhydride and propylene oxide/allyl glycidyl ether during the polymerization. The simultaneous addition of both monomer mixtures provided poly(ether carbonate)s with AXA triblock structures. Both types of polyunsaturated poly(ether carbonate)s are characterized by diverse functional groups, that is, terminal hydroxy groups, maleate moieties along the polymer backbone, and pendant allyl groups that allow for versatile polymer chemistry. The combination of double bonds substituted with electron‐acceptor and electron‐donor groups enables particularly facile UV‐ or redox‐initiated free‐radical curing. The resulting materials are transparent and highly interesting for coating applications.     

Electronitiated polymerization of maleic anhydride by direct electron transfer

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.     

Poly(cyclohexene oxide)/clay nanocomposites by photoinitiated cationic polymerization via activated monomer mechanism

Poly(cyclohexene oxide) (PCHO)/clay nanocomposites were prepared by in situ photoinitiated activated monomer cationic polymerization. The polymerization of cyclohexene oxide through the interlayer galleries of the clay can provide distribution of the clay layers in the polymer matrix homogenously and results in the formation of PCHO/clay nanocomposites. The exfoliated structures were characterized by X‐ray diffraction spectroscopy, thermogravimetric analysis, transmission electron microscopy, and atomic force microscopy. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5328–5335, 2009     

Terpolymerization of sulfur dioxide or maleic anhydride with unsaturated compounds under ultraviolet irradiation

The effect of ultraviolet irradiation on the terpolymerization was investigated. In the terpolymerizations of sulfur dioxide–butene-1–acrylonitrile, sulfur dioxide–butene-1–n-butyl acrylate, and maleic anhydride–allyl chloride–acrylonitrile systems, the composition of the terpolymers prepared under ultraviolet irradiation was different from those prepared in the dark. The unit content of sulfur dioxide and butene-1 or of maleic anhydride and allyl chloride in the terpolymer increased under ultraviolet irradiation. The nature of the growing end under ultraviolet irradiation is supposed to be the same as that of the dark polymerization on the basis of the same solvent effect on the terpolymer composition, the rate of polymerization and the molecular weight of polymer. The experimental results suggest that the complex between sulfur dioxide and butene-1 or maleic anhydride and allyl chloride might be excited by ultraviolet light and the excited complex may participate in the terpolymerization.     

Polymerization of cyclic ethers in the presence of maleic anhydride. Part I. Polymerization of trioxane and 3,3-bis(chloromethyl)oxetane by γ-rays,ultraviolet light,and benzoyl peroxide

Cyclic ethers such as trioxane and 3,3-bis(chloromethyl)oxetane have been polymerized easily in the presence of maleic anhydride by the irradiation of γ-rays and ultraviolet light. The polymer formed is a homopolymer of cyclic ether. The rate of polymerization is accelerated by suitable amounts of oxygen which is required to form some active species at the initiation step. The polymerization is inhibited by the addition of a small amount of radical scavenger, thus suggesting a radical initiating mechanism. In addition, the polymerization is easily initiated by benzoyl peroxide even in vacuo at or above 50°C. Diaroyl and diacyl peroxides are also effective, and polymerization also proceeds in the presence of chloromaleic anhydride, exactly in the same manner as in maleic anhydride. On the other hand, it is well known that polymerization of these cyclic monomers rarely occurs with radical catalysts and easily with cationic catalysts in the absence of maleic anhydride. From these results, it may be concluded that the polymerization is brought about by means of a radical–cationic species.     

γ- and ultraviolet-radiation-induced solid-state polymerization of maleimide in a few binary systems

The solid-state polymerization of maleimide by γ- and ultraviolet irradiation was carried out in binary systems with succinimide, maleic anhydride, and acenaphthylene. Polymaleimide obtained from the solid-state polymerization of maleimide by γ-rays was amorphous, while that obtained from the solid-state polymerization by ultraviolet rays was highly crystalline. In the maleimide–succinimide system the rate of polymerization reached a maximum nearly at the eutectic composition when the polymerization was carried out by γ-irradiation. With ultraviolet irradiation the rate of polymerization became higher with increasing content of succinimide in the feed. In the maleimide–maleic anhydride system a copolymer of both constituents was formed by γ-irradiation, but almost no homopolymer was produced. On the other hand, two kinds of polymers, a crystalline copolymer and an amorphous one, were produced by ultraviolet irradiation. The results were compared with those obtained from the copolymerization in solution. In the maleimide-acenaphthylene system the main products with ultraviolet irradiation was the dimer of acenaphthylene.     

Copolymerization of CO2 and cyclohexene oxide

Generation of high value polymers from carbon dioxide is of general technological interest given that CO2 is both inexpensive and relatively easy to handle on an industrial scale. Previous work on the use of CO2 as a comonomer has focused primarily on development of new catalysts, and the effects of conventional process variables such as temperature and concentration on the polymerization outcome have not been examined in great detail. Recently, we, as well as Darensbourg and colleagues, have shown that one can generate zinc-based catalysts for the polymerization of CO2 and cyclohexene oxide which produce over 400 grams of polymer per gram of metal. In this paper, we use a product of the reaction between zinc oxide and the fluorinated half-ester of maleic anhydride to generate copolymers of CO2 and cyclohexene oxide where CO2 is both reactant and sole solvent. In general, we found that the outcome of the polymerization depends greatly on the proximity to the ceiling temperature and the critical cyclohexene oxide concentration, and also on the phase behavior of the cyclohexene oxide-CO2 binary.     

Polymers from renewable resources. II. A study in the radio chemical grafting of poly(styrene‐alt‐maleic anhydride) onto cellulose extracted from pine needles

A binary mixture of styrene and maleic anhydride has been graft copolymerized onto cellulose extracted from Pinus roxburghii needles. The reaction was initiated with gamma rays in air by the simultaneous irradiation method. Graft copolymerization was studied under optimum conditions of total dose of radiation, amount of water, and molar concentration previously worked out for grafting styrene onto cellulose. Percentage of total conversion (Pg), grafting efficiency (%), percentage of grafting (Pg), and rates of polymerization (R_p), grafting (R_g), and homopolymerization (R_h) have been determined as a function of maleic anhydride concentration. The high degree of kinetic regularity and the linear dependence of the rate of polymerization on maleic anhydride concentration, along with the low and nearly constant rate of homopolymerization suggest that the monomers first form a complexomer which then polymerizes to form grafted chains with an alternating sequence. Grafting parameters and reaction rates achieve maximum values when the molar ratio of styrene to maleic anhydride is 1 : 1. Further evidence for the alternating monomer sequence is obtained from quantitatively evaluating the composition of the grafted chains from the FT‐IR spectra, in which the ratio of anhydride absorbance to aromatic (CC) absorbance for the stretching bands assigned to the grafted monomers remained constant and independent of the feed ratio of maleic anhydride to styrene. Thermal behaviour of the graft copolymers revealed that all graft copolymers exhibit single stage decomposition with characteristic transitions at 161–165°C and 290–300°C. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1763–1769, 1999     

Radiation-induced solid-state copolymerization of maleic anhydride and acenaphthylene

Radiation-induced solid-state copolymerization of the maleic anhydride–acenaphthylene system was carried out for the purpose of studying the solid-state polymerization of vinyl compounds in a binary system. Melting point measurement confirmed that this binary monomer system forms a eutectic mixture in the solid state. The solid-state polymerization of these monomers proceeds at maximum rate at the eutectic composition, and the polymerization products consist of a mixture of polyacenaphthylene and 1:1 maleic anhydride–acenaphthylene alternating copolymer. Since the 1:1 copolymer was obtained in solution polymerization also and maleic anhydride did not homopolymerize in solid state, it is considered that the solid-state copolymerization of maleic anhydride and acenaphthylene occurs in a liquidlike state at the boundary of the two monomer crystals.     

Co(Ⅲ)官能化SBA-15的制备、表征及其催化环己烯环氧化

通过环戊二烯基修饰的SBA-15(SBA-15-Cp)与马来酸酐的Diels-Alder反应及水解合成了邻二羧酸官能化的SBA-15,并将原位生成的Co(Ⅲ)络合物负载于其上制得Co(Ⅲ)官能化SBA-15样品SBA-15-Co(Ⅲ).傅里叶变换红外光谱、元素分析和X射线光电子能谱法结果证实羧酸官能团和Co(Ⅲ)成功地...     

Cyclo- and cyclized diene polymers. XVI. Nature of the active species and a proposed mechanism of cyclopolymerization of isoprene with catalysts containing ethylaluminum halides

The polymerization of isoprene with C₂H₅AlCl₂ to yield solid cyclopolyisoprene is markedly accelerated by the addition of TiCl₄. The polymer yield passes through a maximum on increasing the catalyst reaction time with or without monomer present. The active species are probably cations formed by dissociation of the reaction product of C₂H₅AlCl₂ and TiCl₄. The polymerization of isoprene with (C₂H₅)₂AlX–TiCl₄ (X = F, Br, Cl) has maximum activity at an Al/Ti mole ratio of 0.75 corresponding to conversion of R₂AlX to RAIX₂ which then reacts with remaining TiCl₄. A proposed mechanism of cyclopolymerization of conjugated dienes involves monomer activation, i.e., conversion to cation radical by one-electron transfer to catalyst cation which is itself neutralized, addition of cation end of monomer cation radical to terminal or internal unsaturation of fused cyclohexane polymer chain, one-electron transfer from “neutral” catalyst to cation on polymer chain which is then transformed to a diradical which undergoes coupling to form a cyclohexene ring. The mechanism of the “living” polymerization involves addition of catalyst-activated monomer to a “dead” polymer with a terminal cyclohexene ring and regeneration of the active catalyst.     

Studies in cyclocopolymerization. V. Further evidence for charge-transfer complexes in cyclocopolymerization

Previous work from this laboratory has shown that certain 1,4-dienes which readily undergo cyclocopolymerization with certain alkenes also form charge-transfer complexes with the same alkenes. The results observed and the proposed cyclocopolymerization mechanism are consistent with participation of the charge-transfer complex as a distinct species in the copolymerization. It was the purpose of this investigation to determine whether there was a dilution effect on the relative reactivities of the monomers in support of the charge-transfer participation concept, and whether the results of a suitable terpolymerization study would also support this postulate. In the divinyl ether–fumaronitrile system, the maximum rate of copolymerization occurred at a monomer feed ratio of 1:2 and the composition of the copolymer was also 1:2 at a total monomer concentration of 3 mole/l. However, when the concentration was progressively lowered to 0.5 mole/l. at the same monomer feed ratio, the fumaronitrile content of the copolymer decreased in a linear manner. In a series of terpolymerization experiments with the divinyl ether–maleic anhydride–acrylonitrile system, it was shown that the divinyl ether–maleic anhydride ratio in the terpolymer was always less than 1:1 and had an upper limit of 1:2, regardless of the feed ratio of the termonomers. These results are consistent with the participation of the charge-transfer complex of divinyl ether and maleic anhydride in a copolymerization process with either maleic anhydride or acrylonitrile as the comonomer.     

Radical cyclocopolymerization of divinyl ether and maleic anhydride. A 13C-NMR study of the polymer structure

The structure of the 1:2 copolymer of divinyl ether and maleic anhydride was investigated by ¹³C-NMR spectroscopy. The polymer contains the bicyclic unit composed of one molecule of each monomer and the maleic anhydride unit. The carbon chemical shift for these units was calculated on the basis of the chemical shift of many model compounds. The major peaks of the cyclopolymer prepared in chloroform were consistent with the presence of the symmetrical bicyclic unit with cis junction and the trans monocyclic anhydride unit. The carbonyl carbon spectrum for the copolymer obtained in a mixed solvent of acetone and CS₂ suggested the predominant formation of the unsymmetrical bicyclic unit. The polymerization process was discussed on the basis of these results.     

Retardation of spontaneous polymerization of formaldehyde by acidic substances

The stability of liquid formaldehyde produced by pyrolysis of α-polyoxymethylene was studied in connection with the presence of impurities in the monomer. Liquid monomer was divided into several fractions by means of the distillation. The stability of each fraction for polymerization is dependent on the order of fraction, that is, the monomer obtained in the early fractions of distillation was much more stable with regard to polymerization than later distillate. Analyses of the monomer fractions indicated that various impurities such as carbon dioxide, water, methanol, and methyl formate were present in the early monomer distillates. From the influence of these impurities on the stability of liquid formaldehyde, it was found that small amounts of carbon dioxide and hydrogen cyanide noticeably depressed the polymerization, and that with acetic acid and maleic anhydride the rate of polymerization decreased with small amounts of these compounds but increased with an excess of additive. On the other hand, the addition of these acidic substances did not affect the molecular weight of the polymer produced. From the fact that the acidic substance retards only the initiation of polymerization, it has been concluded that the spontaneous polymerization of formaldehyde in bulk or in toluene solution is initiated by an anionic species.     

修饰硅胶表面印迹牛血红蛋白及其识别性能的研究

本文选用马来酸酐修饰后的硅胶作为载体,丙烯酰胺为功能单体,N,N’-亚甲基双丙烯酰胺为交联剂,牛血红蛋白为模板分子,采用氧化还原悬浮聚合法,合成了具有选择性识别的牛血红蛋白分子印迹聚合物。并用红外光谱(IR)、扫描电子显微镜(SEM)对聚合物进行了表征,结果表明载体表面成功接枝了分子印迹聚合物薄层。同时,选择性吸附实验表明分子印迹聚合物的具有良好的识别性能,能成功的实现水溶液中牛血红蛋白的富集。     

聚苯乙烯-g-聚乙二醇的制备及其表面改性作用

通过沉淀聚合方法,利用自由基共聚制备了苯乙烯-顺丁烯二酸酐共聚物(SMA),利用SOCl2的酰氯反应,在SMA大分子链上接枝聚乙二醇侧链,制备了聚苯乙烯-g-聚乙二醇(PEG-g-PS)的大分子表面改性剂。利用大分子表面改性剂在聚苯乙烯基体中具有选择性迁移扩散的特性,实现了对聚苯乙烯薄膜表面极性的改善作用。采用衰减全反射傅立叶变换红外光谱仪和表面静态接触角法检测了聚苯乙烯的表面极性。结果发现,PEG-g-PS上的聚醚链段可以有效的富集在聚合物表面,明显改善PS的表面极性和亲水性,表面极性可提高3倍,达到11.6mN/m。同时,大分子表面改性剂和聚苯乙烯基体间有一定的相容性,有效地克服了小分子表面改性剂容易流失,改性寿命较短的重要缺陷,使表面改性的持久性充分增加,实现对聚合物表面改性效果终生化的目的。而且大分子表面改性剂在极性溶剂的诱导作用下,可以实现进一步的迁移扩散,充分提高了聚苯乙烯的表面极性。