Vinyl polymerization by metal complexes. V. Effects of amines on the polymerization by copper(II) chelate and carbon tetrachloride initiating system

The polymerization of acrylonitrile was studied by the system of copper(II)-oligo(n)ethylene-(n+1)amine complex and carbon tetrachloride. Addition of amines to the initiating system accelerates the polymerization. The acceleration by these amines was found to be in the following order: prim.-amine<sec.-amine<tert.-amine<diamine<phenylenediamine. Effects of the sort of the ligands in the copper(II) chelates on the polymerization were also studied.     

Emulsifier‐free emulsion polymerization of acrylonitrile: Effect of in situ developed Cu(II)/glycine chelate complex initiated by monopersulfate

The catalytic effect of various Cu(II) salts and Cu(II) chelate complexes of certain amino acids on the emulsion polymerization of acrylonitrile in the absence of added emulsifier was investigated in experiments. The CuSO₄/glycine chelate complex was chosen for a detailed kinetic study of acrylonitrile polymerization. The polymerization was studied at varying concentrations of initiator, monomer, Cu(II), glycine, solvents, and TiO₂ over a temperature range of 30–60°C. The overall activation energy and the viscosity average molecular weight of the polymer were computed. From the kinetic and spectrophotometric studies, the mechanism of KHSO₅ decomposition by the Cu(II)/glycine complex and initiation of polymerization was suggested. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2785–2790, 1999     

Vinyl polymerization by metal complexes. XVIII. Kinetics of the polymerization of acrylonitrile initiated by imidazole-copper-(II) complexes

A study on the kinetics and mechanism of the polymerization of acrylonitrile initiated by imidazole and 2-substituted imidazole-copper-(II) complexes was made in dimethyl sulfoxide solution at 40–70°C. The rate of polymerization, Rp, could be expressed as follows: The overall activation energies of these polymerization processes are in a range from 14.2 to 69.1 KJ mole^-1. From the data of electronic spectra and electron paramagnetic resonance, it was confirmed that the polymerization in question could be initiated by free radicals which were formed by the reduction of copper-(II) complex to copper-(I) complex, and the latter formed a new complex with polyacrylonitrile resulted.     

Radical polymerization of acrylonitrile initiated by α-picolinium p-chlorophenacylid

The radical polymerization of acrylonitrile (AN) with α-picolinium p-chlorophenacylid (α-PCPY) as initiator using carbon tetrachloride as inert solvent was investigated at 50°C. The polymerization follows ideal kinetics: the exponent values calculated for the initiator and monomer were found to be 0.5 and unity, respectively. A free radical mechanism with bimolecular termination was confirmed by the inhibiting effect of hydroquinone, a radical quencher. The rate of polymerization was a direct function of initiator (α-PCPY) concentraction, monomer (AN) concentration and temperature. The overall activation energy calculated was 56 kJ/mol. The polymerization was favoured by polar solvents and retarded by non-polar solvents.     

Vinyl polymerization by metal complexes. XVI. Photopolymerization of vinyl monomers by metal-amine systems

The photopolymerization of vinyl monomers was studied by the system of metal-amine complex and carbon tetrachloride. Addition of amines to the initiating system generally accelerates the polymerization. The acceleration by various sorts of amines in different solvents was examined. It was confirmed that the photopolymerization in question is of free radical character. The polymerization mechanism was discussed.     

Vinyl bromide polymerization with alkylboron and alkyl halide catalyst

Trialkylboron–alkyl halide catalyst systems were found to induce the polymerization of vinyl bromide and other vinyl monomers at low temperatures. Tri-n-butylboron is the most effective catalyst. Among alkyl halide, carbon tetrachloride gives the best yield of poly(vinyl bromide). The polymerization process can be controlled by adjusting the reaction conditions of the initiating components. The rate of polymerization varies depending on the diluent.     

Polymerization of methyl methacrylate by metallocenes

Attempts at polymerizing methacrylate using metallocenes are reported. Polymerization is successful using ferrocene in a ketone solution, but not in benzene or without a solvent. Ketones are effective in the order: methyl ethyl ketone < cyclohexanone < cycloheptanone. Carbon tetrachloride has an accelerative effect on the polymerization in benzene and methyl ethyl ketone solutions, but no effect in cyclohexanone solution. Some binary systems, which consist of ferrocene and higher valence compounds such as cobalt trisacetylacetonate, are effective redox initiators. Cobaltocene polymerizes methyl methacrylate in the presence of carbon tetrachloride; zirconocene dichloride induces polymerization of methyl methacrylate in a cyclohexanone solution; whereas neither nickelocene nor titanocene dichloride are effective. Styrene and acrylonitrile were not polymerized by the metallocenes examined.     

Polymerization of acetylene derivatives induced by UV irradiation via metal carbonyls

Summary The polymerization of phenylacetylene induced by UV irradiation of W(CO)₆ in carbon tetrachloride provided in high yield a polymer, whose molecular weight reached about 80,000. The polymerization did not proceed without UV irradiation or in the absence of a halogen-donating agent such as carbon tetrachloride. On the other hand, the polymerization of 2-chloro-1-phenylacetylene was best effected by Mo(CO)₆, and did not require any halogen-donating agent (polymer MW 400,000). Polymerization of other acetylene derivatives was also examined.     

Photocopolymerization of Methyl Vinyl Ketone with Acrylonitrile by Direct Monomer Irradiation

Summary Irradiation of methyl vinyl ketone (MVK)/acrylonitrile(AN) mixtures gives facile copolymerization accompanied by small molecule formation. A free radical polymerization mechanism is supported by copolymer formation, absence of solvent polarity effect, and inhibition by TEMPO. Small molecules, presumably cyclobutanes, are favored in dilute solutions and form competitively with copolymer. The excited triplet MVK biradical is identified as the initiating species.     

Atom transfer radical polymerization of acrylonitrile

Iron(II) chloride coordinated by succinic acid was first used as the catalyst in 2‐chloropropionitrile‐initiated atom transfer radical polymerization (ATRP) of acrylonitrile. N,N‐dimethylformamide was used as a solvent to improve the solubility of the ligand. An iron(II) chloride to succinic acid ratio of 0.5 not only gives the best control of molecular weight and its distribution but also provides rather rapid reaction rate. Effects of solvent on polymerization of acrylonitrile were also investigated. The induction period is shorter in N,N‐dimethylformamide than in propylene carbonate and toluene and the rate of the polymerization in N,N‐dimethylformamide is fastest. The molecular weight of polyacrylonitrile agrees reasonably well with the theoretical molecular weight of N,N‐dimethylformamide. The rate of polymerization increases and the induction period becomes shorter with increasing polymerization temperature, and the apparent activation energy was calculated to be 56.5 kJ mol^?1. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1050–1054, 2006     

Ring-opening polymerization of 2-oxazolines initiated by chloromethyl groups introduced onto carbon black surface

Summary The ring-opening polymerization of 2-oxazolines (OXZs) was found to be initiated by chloromethyl groups introduced onto carbon black surface. The introduction of chloromethyl groups onto the surface was achieved by the reaction of carbon black with 3,3-bischloromethylbenzoyl peroxide in carbon tetrachloride. During the polymerization, poly-OXZs were grafted from carbon black based on the propagation of the polymers from the surface: percentage of grafting increased with an increase of conversion and reached 40–60%. The polymerization was accelerated by the addition of potassium iodide. Poly-OXZ-grafted carbon black produced stable colloidal dispersions in both hydrophobic and hydrophilic solvents.     

Redox polymerization: Kinetics of polymerization of acrylonitrile initiated by the system 2,2′-thiodiethanol/trichloroaquobipyridylmanganese(III) in dilute sulfuric acid

The kinetics of polymerization of acrylonitrile and methyl methacrylate initiated by the redox system 2,2′-thiodiethanol/trichloroaquobipyridylmanganese(III) have been investigated in the temperature range 20–35°C in dilute sulfuric acid. The oxidation of the substrate in the absence of monomer has also been studied. A third-order reaction involving the complex, the substrate, and H⁺ leads to the production of primary radicals which initiate polymerization of the monomers. The primary radicals are more reactive towards methyl methacrylate than towards acrylonitrile. The termination of polymerization with both monomers is by mutual interaction between the growing radicals. A suitable kinetic scheme has been proposed, and the rate constants evaluated.     

Effect of shear rate on solution polymerization of acrylonitrile

Application of shear is found to increase the rate of solution polymerization of acrylonitrile in N,N-dimethyl formamide (DMF) initiated by benzoyl peroxide by as much as 400 percent of the value in absence of shear. The solvent DMF acts as an inert and maintains a homogeneous reaction mass during the entire course of polymerization. To study the effect of shear systematically, a special dilatometer has been constructed such that a constant shear rate, \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop \gamma \limits^. $\end{document} could be applied to the reaction mass. The rule of solution polymerization has been measured under the variation of \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop \gamma \limits^. $\end{document} and monomer concentration in the system. The measurements of induction time on the addition of a strong inhibitor, hydroquinone, reveal that the increase in the rate of polymerization with shear rate can be largely attributed to the change in the initiator efficiency. As a further confirmation of the above hypothesis, the decomposition of benzoyl peroxide in nitrobenzene at 80°C was measured and was found to increase significantly on application of shear. This confirms the importance of mass-transfer resistance in removal of CO₂, and the increase in the rate of polymerization of acrylonitrile occurs because the decomposition of benzoyloxy radicals is favored in the forward direction. Since the polymerization of acrylonitrile is preferentially initiated by phenyl radicals, the rate of polymerization is found to increase.     

Synthetic and spectroscopic studies of chelate polymers involving azelaoyl bis‐N‐phenyl hydroxamic acid with transition metal ions

Chelate polymers of azelaoyl bis‐N‐phenyl hydroxamic acid with Mn(II), Co(II), Ni(II), and Zn(II) were synthesized for the first time in a dimethylformamide (DMF) medium. These newly synthesized chelate polymers were characterized on the basis of several analytical techniques, namely, elemental analyses, infrared and reflectance spectral studies, magnetic moment, and thermal analyses. On the basis of data obtained with these techniques, the composition of the polymeric units, the structure, and the geometry were ascertained. It was found that the Mn(II) and Zn(II) chelate polymers had a tetrahedral geometry, whereas the Co(II) and Ni(II) chelate polymers were octahedral. Thermal analytical data clearly indicated that the Ni(II) chelate polymer was highly thermally stable relative to the Mn(II), Co(II), and Zn(II) chelate polymers. Since these chelate polymers are highly insoluble in almost all the organic solvents, including alcohol, acetone, chloroform, carbon tetrachloride, DMF, and DMSO, and have high thermal stability, they may be used as surface‐coating materials and as thermally stable materials. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 273–278, 2006     

Graft polymerization of N,N-dimethylaminoethylmethacrylate onto polycarbonates by the preirradiation method

Summary Radiation-induced graft polymerization of N,N-dimethylaminoethylmethacrylate (DMAEMA) from solutions in carbon tetrachloride or in chloroform onto bisphenol A-derived polycarbonate (PC-1) and allyl diglycol carbonate (PC-2), respectively, was carried out by method of preirradiation in air. It has been found essential difference in transparency and durability of the modified PC-1 and PC-2. Effects of preirradiation dose as well as temperature and time of graft polymerization on effectiveness of DMAEMA grafting onto PC-2 were investigated, the optimal values of dose and temperature are 500 kGy and 55°C, respectively. Received: 6 June 1999/Revised version: 9 September 1999/Accepted: 9 September 1999     

Polymers containing metal chelate units. V Modification of a polyethylene surface by post-grafting polymerization of palladium(II) chelate monomers

The synthesis of palladium(II) chelate monomers involving 1-phenyl-4-methylpent-4-en-1,3-dione and 1 phenyl-3-anilino-4-methylpent-4-en-1-one has been developed. New polymer-containing metal chelate units have been prepared by post-grafting polymerization of these monomers and the products characterized by elemental analysis and IR spectroscopy. The catalytic properties of the immobilized complexes in chloronitrobenzene hydrogenation have been studied.     

碳纤维用聚丙烯腈聚合的研究进展

详细综述了丙烯腈的均相溶液聚合、水相悬浮聚合、水相沉淀聚合、混合溶剂聚合及其他聚合方法,介绍了丙烯腈共聚单体的选择和工艺条件对聚合过程的影响。     

OXIDATION AND REDUCTION OF MANGANESE ACETYLACETONATE COMPLEXES IN SOLVENT EXTRACTION SYSTEMS AND IN ORGANIC SOLVENTS BY ATMOSPHERIC OXYGEN

Partial oxidation of manganese(II) and Partial reduction of manganese(III) in acetylacetonate complexes occured in liqudd-liquid systems containing carbon tetrachloride and an aqueous sodium perchlorate solution buffered by sodium hydrogenecarbonate solution equilibrium was assumed to be established after a two phase agitation for several days. Howeve, when the manganese(II) complex was dissolved in air-saturated nonpolar organic solvents such as carbon tetrachloride benzene, and chloroform, it was quantitatively oxidized to the trivalent complex within one hour and the rate was dependent on both the oxygen and ligand. The rate was lower when the solvent was polar and also when an adduct-forming ligand with the bis-chelate such as trioctylphosphine oxide was added into carbon tetrachloride.     

The polymerization of styrene catalyzed by n-butyllithium in the presence of carbon black

The polymerization of styrene catalyzed by n-butyllithium has been carried out in the presence of carbon black at 0°C in toluene. A large portion of the catalyst was consumed by the reaction with the carbon black surface and thus the growth of polystyrene anions on the surface was hindered to a considerable extent. The typical retardation of conversion of styrene monomer to polymer does not change even in the presence of carbon black pretreated with sodium borohydride solution. The intrinsic viscosities of the homopolymers formed in the presence of carbon black were found to be higher than those of the ones formed in the absence of carbon black. On the other hand, the addition of carbon black during the anionic polymerization of styrene was found to promote grafting the growing polymer anions onto the surface of carbon black, consequently giving polymer-grafted particles, while hindering the conversion of styrene into polymer. However, little grafting was observed when the carbon black pretreated with sodium borohydride solution was used. The phenomena indicate that quinonic groups present on the surface of carbon black may be responsible for the capture of growing polymer anions.     

黄原酸酯调控的氯乙烯的可逆-加成断裂链转移聚合

以三种不同结构的黄原酸酯为调控剂,进行氯乙烯（VC）溶液和细乳液可逆加成-断裂链转移（RAFT）聚合,发现O-乙基黄原酸丙酸乙酯对VC聚合的调控效果良好,氯乙烯RAFT细乳液聚合速率明显大于溶液聚合,VC聚合12 h转化率大于90%,但聚氯乙烯（PVC）的分子量分布宽于溶液聚合产物。核磁共振和紫外可见吸收光谱分析证明合成的PVC具有黄原酸酯基端基结构,结构缺陷少。含黄原酸酯基PVC可进一步调控VC及醋酸乙烯酯聚合,进行扩链或得到嵌段共聚物。结合聚合动力学,说明黄原酸酯调控的氯乙烯聚合具有活性特征。