Thermal behavior of cellulosic graft copolymers. II. Cotton grafted with binary mixtures of vinyl acetate and methyl acrylate

Thermal degradation of cotton, mercerized cotton, cotton grafted with vinyl acetate-methyl acrylate mixtures at different compositions, and mercerized cotton grafted with vinyl acetate–methyl acrylate mixture at a composition of 60 : 40 has been investigated using the techniques of thermogravimetric analysis (TGA) and differential thermal analysis (DTA) in nitrogen. The kinetic parameters E, n, and A have been obtained following several methods of thermogravimetric analyses. The mercerization shows a little effect upon thermic properties of cotton cellulose, making cotton thermally more stable. Graft copolymerization of vinyl acetate-methyl acrylate mixture makes cotton thermally less stable if the composition of the copolymer grafted is 100, 90, and 70 mol % VA, while in the case of cellulose graft copolymers with compositions of VA–MA of 80 : 20, 20 : 80, 5 : 95, and 0 : 100 the thermal stability is higher than that of original cotton. The thermal stability of the mercerized cotton grafted with vinyl acetate-methyl acrylate mixture with a composition of 60 : 40 depends on the percent grafting yield. The thermal stability of mercerized cotton grafted with the monomer mixture is higher than that of cotton grafted with that monomer mixture. The degradation of cellulose and cellulose graft copolymers is complex as is shown by DTA thermograms and kinetic parameters.