PHOTO-INDUCED GRAFT POLYMERIZATION OF METHYL METHACRYLATE ONTO CELLULOSE WITH SODIUM PERIODATE

Abstract

The photo-induced graft polymerization of MMA onto cellulose was carried out using NaIO4 as an initiator. The following results were obtained.Graft polymerization of MMA onto cellulose in an aqueous system was accelerated with a small amount of NaIO4 and the optimum concentration was 3_??_5 mmol/l. The degree of grafting and the apparent numbers of grafted chains increased when cellulose was grafted at pH 5.4 and the time of treatment with NaIO4 was prolonged (C=O content <20 mmol/100g cellulose). The apparent activation energies for the over all and the grafting calculated from the initial polymerization rates were 10.7 and 11.3 kcal/mol, respectively. These results show that the graft polymerization proceeds mainly via the photolysis of the carbonyl groups produced by the reaction between cellulose and NaIO4, However, the carbonyl contents increase over 20 mmol/100g cellulose, then the termination between cellulose radicals made by the photolysis and growing polymer radicals occurs more easily than the addition of the monomer onto cellulose radicals.On addition of an organic solvent in the polymerization system, the degree of grafting, the graft chain length and the apparent numbers of grafted chains were affected by the chain transfer of cellulose radicals to the solvent and the affinity with the monomer and cellulose. When NaIO4 was added in the AIBN polymerization system, the graft chain length decreased and the apparent numbers of grafted chains increased.