Abstract
Although Ziegler catalized synthetic cis-1, 4-polyisoprene resembles natural rubber, the latter shows a marked superiority in green strength.The purpose of this paper, therefore, is to investigate why natural rubber shows such superiority in green strength, and thus the relationship between stress-strain curve and linear viscoelastic properties has been investigated.Moreover, molecular characteristics of natural rubber and synthetic cis-1, 4-polyisoprene and interactions between rubber molecuies and fillers have been studied in order to analyze differences in above-mentioned relationships between natural rubber and synthetic rubbers.
The superiority of natural rubber in green strength may be caused by higher mean molecular weight and broader distribution of molecular weight in case of unfilled rubber, and by higher crystallizability and stronger interaction between rubber molecules and fillers in addition to higher mean molecular weight and and broader distribution of molecular weight in case of filled rubber.
