Nitric acid digestion and crystallinity of ethylene–vinyl acetate copolymers

Nitric acid digestion studies of ethylene–vinyl acetate copolymers indicated that copolymers containing identical amounts of vinyl acetate but varying in melt index differed in crystallinity. These results were confirmed by x-ray analysis. The differences in crystallinity were interpreted as showing a variation in the degree of short-chain branching in the polyethylene segments of the copolymer chain. This variation was correlated with the conditions of synthesis.