MATRIX-INDUCED VARIATION IN KINETICS AND CONTROL OF MOLECULAR WEIGHT OF METHACRYLIC ACID POLYMERS DURING GRAFT COPOLYMERIZATION WITH STARCH

摘要

Polymerization of synthetic monomers is known to be influenced by the solvent, initiator system, dilution, temperature, etc. Substrates like starch granules, when used for graft copolymerization, can be expected to provide a drastically different environment for the monomers (as compared to the bulk of the solvent medium), and therefore we predicted this to influence the kinetics of polymerization and stereoregularity of the synthetic polymer. This was investigated with respect to polymerization of methacrylic acid with starch. The rate of methacrylic acid polymerization was found to be significantly higher in grafting with starch as compared to homopolymerization in the absence of starch. Control of molecular weight of the grafted chains was achieved by use of chain transfer agents, and the chain transfer constants for graft copolymerization were determined for two chain transfer agents. The polydispersity of the grafted chains was also found to be dependent on the chain transfer agents. (C) 1997 John Wiley & Sons, Inc. [References: 11]