Vinyl Polymerization. 287. Polymerization of Methyl Methacrylate Initiated by the Polyacrylonitrile-Water-Cupric Ion System

Abstract

Methyl methacrylate was found to be polymerized by the system polyacrylonitrile-water-cupric ion without any added initiator. Addition of carbon tetrachloride to this system greatly increased the polymerization rate. Acrylonitrile and styrene did not polymerize in this system. The kinetic behavior of polymerization was the same as the system consisting'of cellulose or nylon instead of polyacrylonitrile. When the flaky polyacrylo-nitrile was swelled or dissolved by the solvent DMF, the conversion and the degree of polymerization of the poly-methyl methacrylate formed decreased markedly. Commercial acrylic fiber also initiated polymerization but the activity was lower than with flaky polyacrylonitrile, even after steam treatment, because of the poor permeability of monomer into the fiber.     

Vinyl Polymerization. 377. Polymerization of Methyl Methacrylate by the System of Lysozyme,Copper(II) Ion,and Water

The polymerization of methyl methacrylate (MMA) initiated by the system lysozyme, copper(II) chloride, and water was carried out. The effect of the amount of each component on the conversion of MMA was studied. The polymerization proceeded through a radical mechanism. Urea, known to be a denaturing agent for protein, was able to promote the polymerization. On addition of urea, it was found that the following three reactions took place: (1) promotion of the polymerization of MMA with lysozyme, Cu(II) ion, and water by the unfolding of the third structure of lysozyme, (2) polymerization initiated by urea and Cu(II) ion, (3) polymerization initiated by the S-S bonds of lysozyme and urea.     

Vinyl Polymerization. 269. Polymerization of Methyl Methacrylate Initiated by p,p'-Dimethoxydiphenyldiazomethane

Using p,p'-dimethoxydiphenyldiazomethane (DMDM) as initiator, the polymerization of methyl methacrylate (MMA) in benzene or in bulk was carried out. The initial rate of polymerization, R_p, was found to be expressed by the following equation:

R_p = k[DMDM]^0.53 [MMA]^0.84

The polymerization was confirmed to proceed by a radical mechanism. The over-all activation energy for the polymerization in benzene was calculated as 19.3 kcal/mole. The rate of thermal decomposition of DMDM was also measured in benzene and the rate equation was obtained as follows:

k_d (sec^?1) = 1.0 × 10¹⁵ exp (^?29.1 kcal/RT) (for 50-80°C)

Explanations of these observations are discussed in connection with those of the preceding papers.     

Vinyl Polymerization Initiated by Peroxydiphosphate. XI. Polymerization of Methyl Methacrylate Initiated by Peroxydiphosphate-Tartaric Acid Redox System

The polymerization of methyl methacrylate was studied using the peroxydiphosphate and tartaric acid redox system as the initiator. The rate of polymerization increases with increasing peroxydiphosphate concentration and the initiator exponent was computed to be 0.5. The rate of polymerization increases with increasing monomer concentration and the monomer exponent was computed to be unity. The reaction was carried out at three different temperatures, and the overall activation energy was computed to be 3.80 kcal/mol. The effect of certain surfactants on the rate of polymerization has been investigated and a suitable kinetic scheme has been proposed.     

Vinyl Polymerization. 386. Polymerization of Methyl Methacrylate Initiated by Imidazole in Aqueous Solution of Copper(II) Chloride

The radical polymerization of methyl methacrylate (MMA) was carried out with the system of imidazole (Im), copper(n) chloride, and water at 85°C. The effects of the amount of each component on the conversion of MMA were investigated. The polymerization proceeded through a radical mechanism. The overall activation energy was estimated to be 28.7 kJ/mole. The conversion of MMA showed a maximum at pH 8-9 of the aqueous solution. The formation of a complex of CuCl₂ with Im, water, and MMA was confirmed by electronic spectra. An initiation mechanism was proposed.     

Vinyl Polymerization. 371. Polymerization of Methyl Methacrylate Initiated by the System of Polyvinylferrocene and Carbon Tetrachloride

The polymerization of vinyl monomers initiated with the system of polyvinylferrocene (PVFc) and carbon tetrachloride (CCl₄) was carried out in dark. Methyl methacrylate (MMA) and acrylonitrile (AN) could be polymerized, while styrene (St) was hardly polymerized under the conditions used. The polymerization proceeded through a free-radical mechanism and was concluded to be initiated by attack of vinyl monomer, having a polarized vinyl group, on the charge-transfer complex of PVFc/CCl₄. In the polymerization of MMA, the initiating ability of PVFc was much larger than that of ferrocene (Fc-H) or poly(ferrocenylmethyl methacrylate) (PFMMA) and was comparable to that of polyferrocenylenemethylene (PFM). The overall activation energy was estimated to be 34.2 kJ/mole.     

Vinyl Polymerization Initiated by Metal Chelates. III. Polymerization of Methyl Methacrylate Initiated by Vanadium(IV) Acetylacetonate Chelates

The polymerization of methyl methacrylate initiated by the vanadium acetylacetonate complex was investigated under a nitrogen atmosphere at 50°C. The effect of concentration of monomer, complex, acid, dioxane, inhibitor, and the effect of temperature on the rate of polymerization were studied. The rate of polymerization was found to increase upon increasing the concentrations of the monomer, the initiator, and the acid. The overall activation energy has been computed from the Arrhenius plot and a suitable kinetic scheme has been proposed.     

Vinyl Polymerization. 350. Polymerization of Methyl Methacrylate Initiated by the System Sodium Polyvinyl Sulfonate)/Ferric Chloride/Water

In an aqueous medium, sodium polyvinyl sulfonate)(PVS-Na) initiated radical polymerization of methyl methacrylate (MMA) in the presence of ferric chloride. The presence of water and Fe(III) ion was essential. The polymerization was concluded to take place in the aqueous phase. The effects of the amount of water, MMA, Fe(III) ion, and temperature on the polymerization were studied. The mechanism of the initiation is discussed.     

Polymerization of Methyl Methacrylate Initiated with Organomanganate Reagents

Organomanganate reagents [R₃Mn]^–Li⁺ (R = Bu, Me) were found to polymerize methyl methacrylate in the presence of potassium tert‐butylate. A conversion of the tacticity of the resulting poly(methyl methacrylate)s from heterotactic (mr = 54%) to isotactic (mm = 58%) was observed upon changing the R group of the initiator from Bu to Me. The addition of triisobutylaluminium was found to efficiently control M̄_w and M̄_w/M̄_n of the resulting polymers.     

Vinyl Polymerization. 431. Vinyl Polymerizations Initiated by Block and Random Poly(Styrene-co-Sodium Methacrylate)

Abstract

The polymerization of some kinds of vinyl monomer was found to occur without an ordinary initiator in aqueous solutions of AB-type block or random copolymers of sodium methacrylate with styrene as a so-called “uncatalyzed polymerization.” Although the spin trapping technique showed that the initiation mechanism by the block copolymer was the same as that by the random copolymer, the initiating ability of the block copolymer was lower than that of the random copolymer. Such results are attributable to the difference in the incorporating ability of monomer into the micelles formed by the block copolymer and into the hydrophobic areas formed by the random copolymer.     

Vinyl Polymerization. 254.∗ Polymerization of Methyl Methacrylate by the System Cellulose-Water-Carbon Tetrachloride

Radical polymerization of methyl methacrylate initiated by the system cellulose-water-carbon tetrachloride was kinetically studied. Results obtained are: 1) The amounts of water, carbon tetrachloride, and cellulose affected the conversion. Michaelis-Menten's equation was applied to the relationship between the rate of polymerization and the amount of MMA. 2) Other methacrylates and acrylates were also polymerized by this system. 3) When methanol or ethanol was used instead of water, some weak polymerization activity was observed. 4) Initiating ability depended on the kind of cellulose used. 5) The activity of cellulose was not changed by washing with boiling water or by solvent extraction. 6) Polymerization was inhibited by the presence of air. 7) Heating in the presence of water and carbon tetrachloride markedly decreased the activity of the cellulose.     

Aqueous Polymerization of Methyl Methacrylate Initiated by the Mn(lll)-Fructose Redox System

The kinetics of vinyl polymerization of methyl methacrylate initiated by the redox system Mn³-fructose were investigated in aqueous sulfuric acid in the temperature range of 20-25°C, and the rates of polymerization and disappearance of Mn³⁺ were measured. The effect of certain water-miscible organic solvents and certain cationic and anionic surfactants on the rate of polymerization has been investigated. A mechanism involving the formation of a complex between Mn³⁺ and fructose whose decomposition yields the initiating free radical with the polymerization being terminated by the metal ion has been suggested.     

Aqueous Polymerization of Methyl Methacrylate Initiated by the Bromate-Thiourea Redox System

The aqueous polymerization of methyl methacrylate initiated by the bromate-thiourea redox system in dilute HC1 has been investigated under nitrogen atmosphere. The rate of polymerization increases with increasing concentration of thiourea in the range 5 × 10^?3?10 × 10^?3 M. The percentage of conversion increases with increasing concentration of the catalyst, but beyond 1.5 × 10^?2 M, there is a decreasing trend in the rate of polymerization. The rate of polymerization increases with increasing monomer concentration, but beyond 0.184 M the polymerization rate decreases due to gel effect. The rate of polymerization increases with temperature up to 35°C and beyond 40°C a decreasing trend is noticed. The effect of water miscible organic solvents, certain neutral salts on the rate of polymerization has also been investigated.     

Vinyl Polymerization Initiated by the Methylated Cyclodextrin/Metal Ion System in Water

The polymerization of the vinyl monomers methyl methacrylate (MMA), benzyl methacrylate, and styrene, has been carried out using methylated cyclodextrins, for example, heptakis(2,6,0-dimethyl)-β-cyclodextrin, and heptakis (2,3,6-0-trimethyl)-β-cyclodextrin. These methylated cyclodextrins were found to initiate polymerization of the vinyl monomers in combination with water and a small amount of Cu(II) ion, in analogy with β-cyclo-dextrin (β-CD). Generally, the initiating ability of the methylated cyclodextrins/Cu(II) ion system for the polymerization of MMA was larger than that of the β-CD/Cu(II) ion system. Moreover, the introduction of a phosphate group into a methylated cyclodextrin molecule was found to increase the initiating ability for the polymerization of MMA.     

Vinyl Polymerization. 282. Vinyl Polymerization Initiated by Dimethylhydroxylamine-Titanous(lll) Chloride Redox System

Abstract

The polymerization of vinyl monomers initiated by dimethylhydroxylamine hydrochloride (DHA)-titanous(III) chloride redox system has been studied in water under a nitrogen atmosphere. In the polymerization of methyl methyacrylate (MMA) initiated by the above system, the rate of polymerization has been found to be proportional to [DHA]^0.5 for DHA concentrations of less than 2.06 × 10^?3 mole/liter, whereas at higher concentrations the rate tends to fall rapidly. The rate has also been found to be proportional to [Ti(m)] ^0.58 and to [MMA] ^1.0. The maximum rate of polymerization has been observed at a 1:1 molar ratio of DHA to Ti(III). The polymerization proceeded via a radical mechanism. The overall activation energy was estimated as 5.5 kcal/mole. It has been suggested that the reduction of dimethylhydroxylamine by titanous(III) chloride yields the dimethylamino radical, which initiates vinyl polymerization. An examination of the initiating capacity of the initiator system for the polymerization of some vinyl monomers has also been made.     

Vinyl Polymerization. 274. Polymerization of Acrylonitrile Initiated by the System Tetramethyl Tetrazene and Co(II) Chloride

Abstract

The binary system of tetramethyl tetrazene (TMT) and Co(II) chloride was used as initiator of acrylonitrile (AN) in dimethylformamide. The initial rate of polymerization (Rp) was found to be expressed by Rp = k[TMT]^0.62[Co(II) chloride]^0.57 [AN]^2.00

The polymerization was confirmed to proceed via a radical mechanism. The over-all activation energy for the polymerization was estimated as 15.1 kcal/mole. On the basis of these results and the product analysis of the reaction between the catalyst components in the absence of monomer, the initiation mechanism of the polymerization is discussed.     

Vinyl Polymerization. CLXXXV. Polymerization of Methyl Methacrylate Initiated with Benzoic Anhydride and Dimethylaniline N-Oxide. Effects of Solvent and the Substituent of the Initiator

Studies on the rate of the reaction of substituted dimethylaniline N-oxide (DMAO) with substituted benzoic anhydride (Bz₂O) and the rate of polymerization of methyl methacrylate (MMA) with their systems were made. The solvent effects on the rate of the reaction of DMAO with Bz₂O and on the polymerization of MMA with the system were also studied.     

二氧化硅负载[C5Me5]2SmMe(THF)引发甲基丙烯酸甲酯聚合

近年来 ,有许多文献报道茂金属催化剂的负载化及其在烯烃聚合中的应用 ,这对发展新型茂金属催化剂和开发新型高分子材料有重要意义 [1,2 ] .我们 [3]曾报道壳聚糖负载稀土催化剂用于甲基丙烯酸甲酯的配位聚合有优良性能 .以五甲基环戊二烯为配体的有机稀土配合物 ,如 [Sm H( C5Me5) ]2 ,[C5Me5]Ln Me( THF) ( Ln=Sm,Yb)等在甲苯中单组分引发甲基丙烯酸甲酯聚合及内酯开环聚合具有许多优异性能[4 ,5] ,但是经负载化的该类催化剂的聚合性能尚未见报道 .本文报道将 [C5Me5]2 Sm Me·( THF)负载于二氧化硅 ,引发甲基丙烯酸甲酯聚合的结…     

Vinyl Polymerization Initiated by Cycloheptaamylose Phosphate Ammonium Salt/Metal Ion System in Water

Cycloheptaamylose phosphate ammonium salt (β-PCD) was found to initiate the radical polymerization of vinyl monomers in combination with water and a small amount of Cu(n) or Fe(III) ion, in analogy with the cycloheptaamylose (β-cyclodextrin:β-CD). The initiating ability of this system was larger than that of the β-CD/metal ion system. Detailed investigations were conducted in order to elucidate a plausible initiation mechanism of this polymerization.