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 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.     

Studies on Aqueous Polymerization of Acryionitriie Initiated by Ce(IV)-Amino Acid Redox Pair

Aqueous polymerization of acryionitriie initiated by the Ce(IV)-glycine redox pair was studied at 35°C under nitrogen. The rate of polymerization, R_p, was found to be approximately proportional to the square of the monomer concentration within the range of 0.140s–1.268 M. R was also found to increase with glycine concentration in the interval 0.1 to 0.4 M and decrease with cerie ion concentration. The activation energy was estimated to be 25.8 kcal/mol. A suitable kinetic scheme was proposed and explained in the light of these experimental findings. The end-group in the polymer was characterized by IR spectra, and the average molecular weight of the polymer was found to be 84,100.     

Kinetics of Aqueous Polymerization of Acrylamide Initiated by Ceric Ammonium Sulfate/2-Mercaptoethanol Redox System

Polymerization of acrylamide monomer, initiated by the redox system involving acidified ceric ammonium sulfate and 2-mercaptoethanol (2-ME) was carried out in an aqueous medium at 25° C. White, rigid polyacrylamide, isolated under controlled experimental conditions, showed a molecular weight of 1.5 × 10⁴ from viscosity measurements. The rate of monomer (M) conversion to polymer was found to be proportional to [M]^1.5, [2-ME]^0.5, and [Ce(IV)]^0.4. Further, the rate of disappearance of ceric ion was observed to be directly proportional to [2-ME] and independent of [M] in the range of 0.16–0.48 mole/liter. The explanation of the above proportionalities is given in terms of a proposed reaction mechanism. Values of the usual rate constants, k_r, k₀/k_t and k_t./k_p ^½ have been computed.     

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.     

Polymerization of Acrylamide Initiated by the Redox System Potassium Persulfate/Lactic Acid,Catalyzed by Silver Ions

The aqueous polymerization of acrylamide initiated by the potassium persulfate/lactic acid system catalyzed by Ag⁺ ions has been studied iodometrically over the temperature range from 35 to 50 ± 0.2°C. The rate of polymerization is governed by the expression R_p ∞ [M]^0.8[K₂S₂O₈]^1.0[Ag]^1.0 The deviation from normal kinetics has been studied. A tentative mechanism of initiation is suggested. The overall energy of activation is 5.52 kcal/mol.     

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.     

Polymerization of Methacrylamide Initiated by the Persulfate/Thiolactic Acid Redox System

The aqueous polymerization of methacrylamide initiated by the ammonium persulfate/thiolactic acid redox system has been studied at 35 ± 0.2°C. The rate of polymerization is governed by the expression, R_p + K_p [MAA] ^1.33 [TLA]^0.22 [ammonium persulfate]^0.6. The deviations from normal kinetics are discussed. A tentative mechanism of initiation is given. The temperature dependence of the rate of polymerization has been studied over the range 30–55°C. The overall activation energy of polymerization is 10.4 kcal/mole.     

Vinyl Polymerization of Ethyl Acrylate Initiated by TI3+-Ascorbic Acid Redox System

The application of polymers at ever-increasing temperatures has given impetus to research on the chemistry of thermal decomposition. In recent years polymers have been used for a variety of high-temperature applications, such as cooking vessels, motor insulation, and re-entry vehicle heat shields. Interest in chemistry of decomposition has been found in such industries as tobacco and grinding-wheels. Because of the vast number of polymers that are available and the variety of applications thousands of papers have appeared in the literature. Rather than give a complete review the purpose of this paper is to give a brief survey of topics that have been emphasized in the author's research, namely kinetics, mechanisms, and gaseous decomposition products at elevated temperatures.     

3-甲基丙烯酰胺基-9-乙基咔唑-过硫酸钾氧化还原体系引发丙烯酰胺聚合

合成了可聚合芳香叔胺-3-甲基丙烯酰胺基-9-乙基咔唑,并与过硫酸钾组成氧化还原引发体系引发丙烯酰胺水溶液聚合,测定了聚合反应动力学,得到了超高分子量的聚丙烯酰胺.     

3—甲基丙烯酰胺基—9—乙基咔唑—过硫酸钾氧化还原体系引发 …

合成了可聚合芳香叔胺－３－甲基丙烯酰胺基－９－乙基咔唑,并与过硫酸钾组成氧化还原引发体系引发丙烯酰胺水溶液聚合,测定了聚合反应动力学,得到了超高分子量的聚丙烯酰胺。     

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 the Thiourea-Mn3+ Redox System

Kinetics of vinyl polymerization initiated by the redox system thiourea-Mn³⁺ were investigated in the temperature range 30–40°C in sulfuric acid, and the rates of polymerization R_p and disappearance of Mn³⁺ have been measured. The effect of certain water-miscible organic solvents and anionic surfactant on the rates of polymerization was investigated. A mechanism involving the formation of a complex between Mn³⁺ and thiourea whose decomposition yields the initiating free radical with the polymerization terminated by mutual intraction of growing radicals is suggested.     

辣根过氧化物酶酶促体系引发丙烯酰胺聚合的研究

对辣根过氧化物酶(HRP)、H2O2和乙酰丙酮(ACAC)组成的三元醇促体系引发的丙烯酰胺(AAM)聚合进行了研究。在膨胀计中考察了反应温度和HRP、ACAC、H2O2及AAM初始浓度对酶促体系引发AAM聚合动力学行为的影响,确定了适宜的反应条件。用FTIR和GPC对聚合产物进行表征,得到的聚丙烯酰胺的数均分子量为10^5-10^6,分子量分布指教DI为2-3。     

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.     

Photograft Copolymerization of Methyl Methacrylate on Wool Using Ce4+ -Oxalic Acid Redox Initiator in a Limited Aqueous System

Abstract

Photograft copolymerization of methyl methacrylate on reduced wool (reduction done by treatment with thioglycollic acid, TGA) was studied at nearly 30°C using a Ce⁴⁺ -oxalic acid redox initiator system in a limited aqueous system (2.7 mL water for 0.15 g wool). Reduction of wool for 16 h with 15% TGA solution produced optimum grafting effects. Percent grafting and grafting efficiency under different sets of conditions were studied and compared, and the mechanism of grafting discussed. Generation of grafting sites (radical centers) on reduced wool was more effective in the presence of light than in the dark. Percent grafting of 250–350% and grafting efficiency of 65-80% over a conversion range of 60–90% in 3–5 h were easily obtained.     

Polymerization of Acrylonitrile: Kinetics of the Reaction Initiated by the Mn3+-Cyclohexanol Redox System

The vinyl polymerization of acrylonitrile initiated by the redox system Mn³⁺-cyclohexanol was investigated in aqueous sulfuric acid in the temperature range of 30–45° C. The rate of polymerization R_p and the rate of Mn³⁺ ion disappearance were measured. The effects of certain water-miscible organic solvents and certain anionic, cationic, and nonionic surfactants on the rate of polymerization were investigated. Based on the results obtained, a suitable reaction mechanism involving the formation of a complex between Mn³⁺ and the alcohol, whose decomposition yields the initiating free radical with the polymer chain being terminated by the mutual combination of growing chains is suggested.     

Polymerization of Acrylonitrile: Kinetics of the Reaction Initiated by the Redox System Mn3/Mannitol

Polymerization of acrylonitrile initiated by the redox system Mn³⁺/mannitol has been investigated in aqueous sulfuric acid in the temperature range 35–50°C. The rate of polymerization R_p and the rate of disappearance of Mn⁺³ (?R_M) were measured. The effect of certain water-miscible organic solvents, inorganic salts and complexing agents on the rate of polymerization have been investigated. Based on the experimental results, a suitable reaction mechanism is suggested involving the formation of complex between Mn³⁺ and the hydroxyl group of the substrate molecule, whose decomposition yields the initiating free radical; the polymer chain is terminated by the mutual combination of growing chains.     

羟丙基甲基纤维素的接枝共聚及其在复合材料中的应用研究

在水溶液中以KMnO4／草酸／硫酸(氧化-还原引发体系)引发甲基丙烯酸甲酯在羟丙基甲基纤维素上的乳液接枝共聚。研究了引发剂组成、反应温度、反应介质的H^ 浓度等对接枝率的影响。结果表明：反应温度和引发剂组成对接枝率有显著影响。接枝纤维素经IR和DTA表征。用接枝纤维素填充聚氯烯(PVC)所得PVC复合材料的拉伸强度提高了20％。     

Polymerization of Acrylonitrile Initiated by the Redox System,K2S2O8-Citric Acid Catalyzed by Silver Ion

The polymerization of acrylonitrile initiated by the redox system K₂S₂O₈-citric acid catalyzed by Ag⁺ ion has been studied over the temperature range 35–50°C. The rate of polymerization is proportional to the square root of peroxydisulfate concentration. The initial rate increases with increasing citric acid concentration, but at relatively higher concentration of citric acid the rate decreases. The rate of polymerization also increases with increasing monomer concentration and temperature. The overall activation energy calculated from the Arrhenius plot was found to be 4.6 kcal/mole. On the basis of the observation, a suitable kinetic scheme has been proposed for the reaction.