Abstract
A study has been made on the impact tensile behaviors of ethylene-based copolymers (containing about 8.3mol-%methacrylic acid units and about 3.9 mol-%acrylic acid units), and of these partially ionized sodium and zinc salts. Sodium salts have an inclination of a ductile fracture and the fracture energy does not depend on degree of ionization. While, zinc salts show a brittle fracture and the fracture energy decreases with increasing degree of ionization considerably. The molecular relaxation of zinc salts could not be in high response to the impact loading in comparison with that of sodium salts. Swelled sodium salts of ethylene methacrylic acid show lower yield strength and higher elongation than dried sodium salts. It is suggested that the ioncluster is destroyed and the hydrocarbon chain is plastcized by increasing humidities.
