Aqueous Polymerization of Methyl Methacrylate Initiated by Potassium Peroxydisulfate-Ascorbic Acid Redox System

The aqueous polymerization of methyl methacrylate initiated by the redox system K₂S₂O₈-ascorbic acid has been studied at 35°C under the influence of oxygen. The rate of polymerization increases with increasing ascorbic acid concentration at low activator concentration, remains constant within the range 4.375 × 10^?3 to 11.25 × 10^?3 mole/liter, and at higher ascorbic acid concentration again decreases. The rate varies linearly with monomer concentration. The initial rate and the limiting conversion increase with increasing polymerization temperature. Organic solvents (water-miscible only) and small amounts of neutral salts like KC1 and Na₂SO₄ depress the initial rate and the maximum conversion. The addition of small amounts of salts like Cu²⁺ and Mn²⁺ increases the initial rate, but no appreciable increase in the limiting conversion is observed.     

Aqueous Polymerization of Methyl Methacrylate Initiated by the Potassium Bromate-Thiomalic Acid Redox System

The redox system composed of potassium bromate and thiomalic acid was used to initiate the aqueous polymerization of methyl methacrylate under nitrogen atmosphere at 35 ± 0.2°C. The initial rates of polymerization have been found to be approximately proportional to the first power of the initiator concentration in the range of 2.5 to 6.0 ± 10^?3 M and to the first power (1.15) of monomer concentration in the range of 3.72 to 11.16 ± 10^?2 M The overall rate was independent of activator concentration, approaching a maximum at 10 × 10^?3 M. The overall energy of activation was found to be 8.80 kcal/mol. The initial rate and the maximum conversion attained a maximum value at 35°C in the temperature range of 20 to 45°C.     

Aqueous Polymerization of Methyl Methacrylate Initiated by Ce4+-Glycolic Acid Redox System

The aqueous heterogeneous polymerization of methyl methacrylate (MMA) initiated by the Ce⁴⁺-glycolic acid (GA) redox system was studied at 35 × 0.2°C under a nitrogen atmosphere. The rate of monomer disappearance was proportional to [MMA]¹[GA]¹[Ce⁴⁺]°, and the rate of eerie ion disappearance was found to be directly proportional to [Ce⁴⁺] and [GA] but independent of [MMA]. The activation energy was found to be 34 kJ/mol. The molecular weight of polymethyl methacrylate increased with increasing [MMA] and decreased with increasing [oxidant]. The effect of increasing [H₂SO₄] on polymerization was also studied. The results are compared with those obtained for the aqueous homogeneous polymerization of acrylamide with the same redox pair.     

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.     

Potassium Bromate-Thiourea Redox Initiated Grafting of Methyl Methacrylate onto Polyethylene Terephthalate

Some kinetic features of the grafting of methyl methacrylate onto polyethylene terephthalate initiated by the potassium bromate-thiourea redox system have been investigated in aqueous solution. The effects of potassium bromate, thiourea, monomer, acid, and temperature upon percentage grafting have been determined. The activation energy of the reaction has been computed from an Arrhenius plot. Grafting experiments have been carried out in the presence of such conventional chain-transfer agents as CC1₄ and CHC1₃. The effect of CuSO₄ upon grafting is also studied. The reaction mechanism involved during grafting is pictured.     

Aqueous Polymerization of Methyl Methacrylate Initiated by Potassium Pervanadate

The aqueous polymerization of methyl methacrylate was kinetically studied using acidic (H₂SO₄) potassium pervanadate as initiator. The initiator exponent was 0.3 and the monomer exponent was 1.0. Polymerization is considered to proceed by a radical mechanism, and termination takes place quite measurably by a degradative initiator transfer mechanism.     

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.     

Aqueous Polymerization of Methyl Methacrylate Initiated by Pyridine-Sulfur Dioxide Complex

The aqueous polymerization of MMA was studied kinetically at 40° C using low concentrations of Py-SO₂ complex as initiator. For [Py-SO₂] < 2 × 10^?2 mol/L, R_p ∞ [PY-SO₂]^0.5 [M]^1.5, and for [Py-SO₂] > 2 × 10^?2 mol/L, R_p ∞ [Py-SO₂]^0,0[M]^1.08. Polymerization is considered to proceed by a radical mechanism. The radical generation or the initiation step is believed to proceed through equilibrium complexation between the Py-SO₂ complex and monomer molecules. For [Py-SO₂] < 2 × 10^?2 mol/L, the polymerization is characterized by bimolecular termination. Above this [Py-SO₂], chain termination by a degradative initiator transfer process assumes prominence.     

Aqueous Polymerization of Methyl Methacrylate

Aqueous polymerization of methyl methacrylate (MMA), initiated by the potassium bromate-thioglycollic acid (TGA) redox system, has been studied at 30 ± 0.2° C under positive pressure of nitrogen. The rate is given by K[MMA] [TGA] ⁰[KBrO₃]^x where × = 1 for lower KBrO₃ concentrations and 0.5 for higher KBrO₃ concentrations. The reaction has been studied over the 20–45°C range. The activation energy was found to be 65.72 kJ/mol (15.71 kcal/mol) in the investigated range of temperature. Inorganic electrolytes except MnSO₄·4H₂O and Na₂C₂O₄ depress both the rate of polymerization and the maximum conversion. All the alcohols (viz., MeOH, EtOH, iso-PrOH, tert-BuOH) and acetone depress the rate of polymerization as well as the maximum conversion.     

硫氰基/有机铜锂体系引发MMA阴离子聚合研究

采用有机锂为引发剂,以甲基丙烯酸酯（MMA）类为单体进行阴离子聚合,其副反应较严重,因为在此类单体分子中存在卢碳和羰基碳两个亲核点,引发剂进攻羰基碳则会使链终止,在聚合过程中发生各种副反应,以碱金属（Li,Na,K）为反离子的有机碳负离子化合物,其亲核性较强,倾向于进攻羰基碳,因此甲基丙烯酸酯类单体的阴离子聚合除了采用较大立体阻碍引发剂外。     

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.     

Redox Polymerization of Methyl Methacrylate in the Fluorous Triphasic System

Fluorous-phase chemistry is currently a topic of considerable interest1-6. Since fluoroustriphasic reactions were first described by the Curran and co-workers7, this triphasicsystem has been widely used for detagging7,8 and phase-vanishing reactions9-11. …     

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.     

Polymerization of Methyl Methacrylate: Kinetics of the Reaction Initiated by the Mn(III)-1,2-Propanediol Redox System

Kinetics of polymerization of methyl methacrylate initiated by Mn³⁺/1,2-propanedlol has been investigated in aqueous sulfuric acid at the temperature range of 25–35°C. The rate of polymerization (R_p) and the rate of manganic ion disappearance (-R_Mn) have been computed. The effects of organic solvents, certain cationic and anionic detergents, added electrolytes on the initial rate of polymerization, and maximum conversion have been examined. Depending on the kinetic results, a reaction scheme has been suggested involving the formation of a complex between Mn³⁺ and the alcohol, which subsequently decomposed in an unimolecular step to generate the initiating free-radical which initiates polymerization and termination of the growing polymer chain by metal ion.     

Studies on the Mechanism of Methyl Methacrylate Polymerization Initiated by Volatile and Nonvolatile Products of Methyl Methacrylate Plasma

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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. 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. 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.