ABSTRACT
This chapter examines how a block of rubber deforms under the influence of an externally applied force. When the block of rubber deforms, each chain making up the block of rubber deforms as well. Changes in the length of individual chains correspond exactly to changes in the length of corresponding lines drawn on the exterior of the bulk rubber. In order to explain the observations made with natural rubber and other elastomers, it is necessary to understand the behavior of polymers at the microscopic level. Models can explain not only the basics of rubber elasticity, but also the qualitative rheological behavior of polymers in dilute solution and as melts. Raw rubber behaves as an elastic solid only over a short time scale. The cause of the latter deviation is strain-induced crystallization in rubber; the crystallites that form at large extension ratios act as cross-links, resulting in an increase in the modulus.
