New Interpretations for Stress-Strain Behavior of Rubber Vulcanizates

Relationship between Stress-Strain Behavior and Change of Network Structure during Deformation Process

Abstract

Change in the cross linking density of rubber vulcanizates with deformation was studied by measuring the degree of swelling of samples experienced extension. Swelling measurements were made in toluene, and the cross linking density was determined by using the Flory-Rehner equation. The decrease in the cross linking density with extension ratio occurred in three stages: rapidly decreasing stages at low and high extension ratios and a slowly decreasing stage in the middle. Stress-strain hysteresis in cyclic extension was observed. A network model was proposed to interprete the observed relation between structure and properties of the deformed rubber vulcanizates.