Aqueous Redox Polymerization of Acrylamide Initiated by Lactic Acid/Permanganate

Acrylamide was polymerized in aqueous solution at 35 ± 0.2°C with the redox pair potassium permanganate/lactic acid. The kinetics of polymerization was followed iodometrically. The effect of monomer, potassium permanganate, and lactic acid concentration and temperature on the rate of polymerization was studied. The dependence of the number-average degree of polymerization on the initial rate of polymerization and temperature was also determined.     

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.     

Hexavalent Chromium-Thioacetamide Redox System Initiated Polymerization of Acrylonitrile

Polymerization of acrylonitrile initiated by the Cr⁶⁺/thioacetamide redox system was studied in nitrogen atmosphere in the temperature range 35–45°C. The rate of polymerization and the rate of Cr⁶⁺ ion disappearance were measured. The effect of certain water-miscible organic solvents, neutral electrolytes, and complexing agents on the rate of polymerization was investigated. Chromic acid alone did not initiate the polymerization under deaerated and undeaerated conditions. Depending on the results obtained, a suitable kinetic scheme was proposed and various rate parameters were evaluated.     

Polymerization of Acrylamide with Permanganate/Mercaptosuccinic Acid Initiator System

The aqueous polymerization of acrylamide initiated by the acidified potassium permanganate/mercaptosuccinic acid redox system was studied at 35 ± 0.2°C in nitrogen. In the studied range of activator concentration (2.0 × 10^?3 to 6.25 ± 10^?3 mole/liter) the polymerization rate remains unaffected. The initial rate of polymerization varies linearly with KMnO₄ and acrylamide concentrations in the studied range. The activation energy was found to be 6.61 kcal/mole (27.63 kJ/mole) in the temperature range of 30–50°C. The molecular weight of polyacrylamide was found to be independent of [KMnO₄] but increased with increasing monomer concentration. The effect of DMF on polymerization rate and molecular weight was also investigated.     

Kinetics of Vinyl Polymerization. 1. Ceric Ion Induced Polymerization of Acrylonitrile in the Presence of Butane-1,4-diol

The kinetics of acrylonitrile polymerization initiated by butane-l,4-diol-Ce(IV) redox system have been studied in aqueous sulfuric acid in the range 30 to 40°C under nitrogen. There is no experimental evidence for the formation of a complex between diol and oxidant; the kinetics are consistent with a linear mode of termination. The effect of certain neutral salts, acids, water-miscible organic solvents, and temperature on the rate of polymerization and the rate of metal ion disappearance have also been investigated. Various rate and energy parameters have been evaluated.     

Retardation of Permanganate-Initiated Polymerization of Acrylonitrile by Phenol

The mechanism and kinetics of the retardation of the permanganate-initiated polymerization of acrylonitrile by phenol have been studied in the temperature range of 30 to 45°C. The effect of monomer, metal ion, phenol, sulfuric acid, organic solvents, and some inorganic salts on the polymerization has been studied. The most remarkable observation in the present investigation was the negative intercept obtained from a plot of [M]/R_p versus 1/[M] of the rate mechanism, This observation appears to be a general phenomenon for all inhibiting substrates. A reaction mechanism has been suggested and a suitable rate law has been proposed.     

无规聚丙烯接枝甲基丙烯酸的合成

采用溶液聚合的方法将无规聚丙烯 (APP)与甲基丙烯酸 (MAA)接枝共聚制得接枝共聚物APP -g -MAA。讨论了反应温度、反应时间、引发剂BPO浓度、单体MAA浓度对接枝率的影响。结果表明 :当聚合反应温度低于是 12 0℃时 ,接枝率随温度升高而降低。延长反应时间有利于提高接枝率。最适宜的引发剂浓度为 1% ,MAA/APP配比为 0 .2 5/1。利用红外光谱证实了接枝物APP-g -MAA的存在。     

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.     

Polymerization of acrylonitrile initiated by thiourea–chromium(VI) redox system

The kinetics of polymerization of acrylonitrile initiated by Cr(VI)–thiourea and Cr(VI)–ethylene thiourea have been studied at 35, 40, and 45°C in nitrogen. The rates of polymerization and of disappearance of Cr(VI) were measured. Chromic acid alone did not initiate the polymerization under deaerated and undeaerated conditions. On the basis of the experimental observation of the dependence of the rate of polymerization R_p, the rate of Cr(VI) disappearance, –R_m, etc., on various variables, a suitable kinetic scheme was proposed and various rate and energy parameters were evaluated.     

Effect of pH on Poly(acrylic acid) Solution Polymerization

The free-radical redox-initiated aqueous solution polymerization of fully and partially neutralized acrylic acid was carried out at room temperature under full exposure to air. The effect of neutralization degree on the polymerization rate and product properties was studied. Increasing neutralization of the reaction mixture with sodium hydroxide resulted in greater conversion of acrylic acid to sodium acrylate. The rate of polymerization, determined from a gravimetric off-line water removal technique, was shown to decrease significantly with decreasing degree of neutralization. Molecular weight also decreased with decreasing degree of neutralization. The glass transition temperature and hydrophilicity of the polymer product decreased with increasing degree of neutralization. In-line infrared monitoring was also used to monitor the reaction progress and was shown to be an effective tool for this purpose.     

A New Redox Initiating System for the Polymerization of Vinyl Monomers

Abstract

A new redox system, dioxane-ascorbic acid, has been investigated for the homopolymerization of vinyl monomers. Detailed kinetic studies on the aqueous polymerization of acrylamide by this initiating system have been done iodometrically at 35 ± 0.2°C. The effect of various additives, such as organic solvents, inorganic salts, surfactants, etc., on the rate of polymerization has been studied. The retardation constants for organic solvents have been evaluated by the “intercept method.” The overall energy of activation has been found to be 8.75 kcal/deg/mol, within the temperature range 25–45°C. A suitable mechanism has been suggested. The following rate expression: R_p α [acrylamide]^1.0 [dioxane]^1.0 [ascorbic acid]⁰, has been observed.     

Polymerization of acrylonitrile by V5+–lactic acid system in aqueous sulfuric acid

Kinetics of polymerization of acrylonitrile by the redox system V⁵⁺–lactic acid in sulfuric acid at 20–35°C was studied. Oxidation of lactic acid by V⁵⁺ in the absence of monomer was also carried out under identical conditions. The rates of polymerization, V⁵⁺ disappearance and the chainlengths of polyacrylonitrile were measured. From the results it is concluded that the polymerization reaction is initiated by an organic free radical arising from the V⁵⁺–lactic acid reaction with termination by V⁵⁺ ions. Mutual termination of active polymer radicals does not appear to operate under the conditions studied. The various rate parameters were evaluated.     

Vinyl Polymerization Initiated by Peroxydiphosphate. IV. Polymerization of Acrylonitrile Initiated by Peroxydiphosphate-Thioacetamide Redox System

Abstract

The kinetics of the aqueous polymerization of acrylonitrile initiated by the peroxydiphosphate-thioacetamide redox system was investigated at 35, 40, and 50°C. The rates of polymerization were measured at different concentrations of oxidant, activator, and monomer. Peroxydiphosphate alone did not initiate polymerization under deaerated and undeaerated conditions. Addition of certain water-miscible organic solvents and neutral salts depress the rate and conversion. On the basis of experimental observations of the dependence of the rate of polymerization on various variables, a suitable kinetic scheme has been proposed.     

Functional Monomers and Polymers L Post-1 rradiative Polymerization of Butadiene in Deoxycholic Acid Canal Complexes

The polymerization of butadiene was studied in deoxycholic acid canal complexes under various reaction conditions. To prepare the starting canal complex containing butadiene, acetone in the deoxycholic acid-acetone canal complex was replaced with butadiene effectively. Post-irradiative polymerization was carried out after irradiation with γ-rays from a Co-60 source. The polymer was found to contain a significant amount of 1,2-units in addition to trans- 1,4-units. Various additives had a marked effect on the polymerization behavior, particularly on the polymer yield and the microstructure of the polymer.     

Effect of Glycerol in the Polymerization of Methyl Methacrylate by Mn(III) Acetate

The kinetics of the mechanism of the polymerization of methyl methacrylate initiated by the glycerol/Mn(III) acetate redox system has been investigated in aqueous sulfuric acid medium in the temperature range of 40 to 50 °C. The effects of glycerol, methyl methacrylate, metal ion, acetic acid, and sulfuric acid on the rates of polymerization have been studied. One striking observation is that the increase in monomer concentration steadily decreases the rate of polymerization, contrary to what was observed in the case of acrylonitrile. On the basis of these observations, an appropriate kinetic scheme and rate expression have been developed.     

Polymerization of acrylamide initiated by Ce4+/L-cysteine redox system

Summary The polymerization of acrylamide initiated by Ce 4⁴⁺/L-cysteine redox system has been studied at 35 ± 0.2 °C in dark under nitrogen atmosphere. The effect of monomer,L-cysteine, Ce⁴⁺ and sulphuric acid concentration and temperature on the rate of polymerization has been studied. The rate may be expressed by the following equation:R _p [M] [Ce⁴⁺]^0.5 [Cysteine]^0.44 The overall energy of activation is 4.78 kcal/deg/mole in the investigated range of temperature 30–50 °C. Molecular weight of the polymer is independent of catalyst concentration but increases with increasing monomer concentration.     

Polymerization of acrylic acid initiated by a hexavalent chromium-organic sulfur compounds reducing agent system

The kinetics of polymerization of acrylic acid initiated by Cr⁶⁺-thiourea, Cr⁶⁺-thioacetamide, Cr⁶⁺-2-aminoethane thiol, Cr⁶⁺-cysteine, and Cr⁶⁺-thioglycollic acid have been studied at 30, 35, and 40°C in nitrogen. The rates of polymerization were measured. Chromic acid alone did not initiate the polymerization under deaerated and un-deaerated conditions. On the basis of the experimental observation of the dependence of the rate of polymerization R_p on various variables, a suitable kinetic scheme is proposed.     

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.     

苯胺乳液聚合条件的研究

以（ＮＨ４）２Ｓ２Ｏ８为氧化剂、在非极性溶剂－功能质子酸－水三相体系中,采用乳液聚合方法合成聚苯胺乳液和粉末。对乳液聚合与化学氧化溶液聚合合成的聚苯胺性能进行了比较,研究了掺杂酸、氧化剂、反应时间、温度和水相浓度等聚合条件对聚苯胺导电性、溶解性、乳液粘度等性能的影响。结果表明,乳液聚合产率大于８０％,聚苯胺电导率大于１Ｓ／ｃｍ,在有机溶剂中的溶解性与用化学氧化合成的聚苯胺相比有明显提高。     

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.