SynopsisThe graft copolymerization of methyl methacrylate onto silk fibers was investigated in aqueous solution using Mn3+ acetyl acetonate [Mn(acac)a] as initiator. The rate of grafting was determined by varying monomer, acidity of medium, temperature, and reaction medium. The graft yield increases significantly with increase of [Mn(acac)a] concentration up to 0.01M, and with further increase of [Mn(acac)a] the graft yield decreases. The effect of the increase of monomer concentration brings about a significant enhancement in the graft yield, and with further increase the graft yield decreases. The rate of reaction is temperature dependent; with increasing temperature, the graft yield increases. Among the solvent composition studied, a watedsolvent mixture containing 10% of the solvent seems to constitute the most favorable medium for grafting; and, with further increase of solvent composition, the graft yield decreases. The effect of some inorganic salts, organic solvents, and complexing agents has been investigated.
A B S T R A C TVinyl polymerization of acrylonitrile initiated by the redox system Mn3+/tartaric acid was investigated in aqueous sulfuric acid in the temperature range 30-50°C, and the initial rates of polymerization, Mn3 + disappearance, etc. were measured. The effects of certain water-miscible organic solvents, neutral electrolytes, dyes, and solid substances on the rate of polymerization have been investigated. A mechanism involving the formation of a complex between Mn3+ and tartaric acid, whose decomposition yields the initiating free radical with the polym e r chain being terminated by mutual interaction of growing radicals, has been suggested.
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