Mohan C. Nayak

Polymerization of Acrylonitrile Initiated by the Thiourea-Mn3+ Redox System

Abstract 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 Rp 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.

Aqueous polymerization of acrylonitrile initiated by the Mn3+/citric acid redox system

Abstract Kinetics of polymerization of acrylonitrile initiated by the redox system Mn 3+ /citric acid were investigated in aqueous sulphuric acid in the range of 20–25°; initial rates of polymerization and Mn 3+ disappearance etc. were measured. The effects of certain water miscible organic solvents and certain cationic and anionic detergents on the rate of polymerization have been examined. A mechanism has been suggested involving formation of a complex between Mn 3+ and citric acid, decomposition of which yields the initiating free radical and with polymerization being terminated by mutual interaction of growing radicals.

Polymerization of Acrylonitrile: Kinetics of the Reaction Initiated by the Mn3+/Ascorbic Acid Redox System

Abstract Vinyl polymerization of acrylonitrile initiated by the Mn3+/ascorbic acid redox system was investigated in aqueous sulfuric acid in the temperature range of 30–45°C. The rate of polymerization Rp and the rate of Mn3+ ion disappearance were measured. The effect of additives like water -miscible organic solvents, neutral salts, complexing agents and different surfactants on the initial rate of polymerization were investigated. Depending on the results obtained, a suitable reaction mechanism is suggested which involves the formation of a complex between Mn3+ ion and the acid whose decomposition generates the initiating free radical, with the polymer chain being terminated by mutual combination of the growing chains.

Acidic peroxo salts: A new class of initiators for vinyl polymerization—II: Kinetics of polymerization of acrylonitrile initiated by potassium monopersulphate catalysed by Mn(II)

Abstract Kinetics of the polymerization of acrylonitrile initiated by an acidic peroxo salt (potassium monopersulphate) catalysed by Mn(II) have been investigated in aqueous systems over the range 30–50°. The rates of polymerization (Rp) have been studied for various concentrations of monomer and initiator. The efficiencies of various metal salts in catalysing the polymerization have been determined from the values of Rp. The effects of catalyst (MnSO4), initiator, monomer and various aromatic and heterocyclic amines on Rp and conversion have been studied. The end-groups of the recovered polymers have been studied using standard methods. From the observed end-groups and kinetic results, a reaction scheme has been proposed, involving initiation by OH. or S O 4. radicals, generated by the interaction of the initiator with manganous sulphate, and termination by mutual combination.

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

Abstract 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 Rp and the rate of disappearance of Mn+3 (−RM) 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.

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

Abstract 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 (Rp) and the rate of manganic ion disappearance (-RMn) 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.

Kinetics of Polymerization of Methyl Methacrylate Initiated by the V5+/Thioacetamide Redox System

Abstract Kinetics of the polymerization of methyl methacrylate has been investigated in aqueous sulfuric acid in the temperature range of 35–50°C in the presence of the redox system V5 +/thioaceta-mide. The rate of polymerization and the rate of V5+ ion disappearance have been measured. The effect of various additives such as water-miscible organic solvents, neutral electrolytes, complex-ing agents, and solvent composition on the rate have been thoroughly studied. A mechanism involving the initial complex formation between the thiol form of the thioacetamide and V5+, whose decomposition yields the initiating free radical, with the polymer chain terminated by metal ion has been suggested.

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

Abstract The vinyl polymerization of acrylonitrile initiated by the redox system Mn3+-glucose has been studied in aqueous sulfuric acid at 30–50°C. The rate of polymerization, the rate of Mn3+ disappearance, etc. were measured. The effect of certain water miscible organic solvents, inorganic salts, dyes, solvent composition, solid substances, and inhibitors on the rate of polymerization has been investigated. Based on the experimental results, a suitable reaction mechanism involving the formation of a complex between Mn3+ and the substrate molecule, whose decomposition yields the initiating free radical with the polymer chain being terminated by the mutual combination of growing chains, has been suggested.

Hexavalent Chromium-Thioacetamide Redox System Initiated Polymerization of Acrylonitrile

Abstract 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 Acrylonitrile Initiated by the Mn(III)/Ethane Thiol Redox System

Abstract Kinetics of vinyl polymerization of acrylonitrile initiated by the redox system Mn(III)/ethane thiol were investigated in aqueous sulfuric acid in the temperature range of 30-45°C. The rate of polymerization, rate of manganic ion disappearance, etc. were measured. The effect of certain water-miscible organic solvents, neutral electrolytes, and organic nitrogen compounds on the rate has been investigated. A mechanism involving the formation of a complex between Mn(III) and the thiol, whose decomposition yields the initiating free radical with the polymerization being terminated by mutual combination of the growing radicals, has been suggested.