【Basic Knowledge of Glossary Definitions for “Polymers and Materials”-017】Glossary definitions related to polymers

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This post was last edited by ljtjbx on 2015-8-10 at 13:51. 1. Crack: Irreversible, as the crack progresses further under significant external forces. 2. Free-bound chain: It is assumed that a polymer is formed by the free combination of a sufficient number of volume-free chemical bonds, with no bond angle restrictions or energy barriers during internal rotation, and each bond has an equal probability of being oriented in any direction. 3. Free-rotating chain: It is assumed that each bond in the molecular chain can rotate freely in the directions permitted by the bond angle, with no account taken of the effect of steric hindrance on rotation. 4. Equivalent freely bonded chain: A chain composed of several chemical bonds can be regarded as a unit that can move independently; this unit is called a chain segment. When these chain segments are freely bonded to each other and arranged in a random manner, it is referred to as an equivalent freely bonded chain. 5. Entropic elasticity: When an ideal elastomer is stretched, only a change in entropy occurs; in other words, it is only the change in entropy that contributes to the elasticity of an ideal elastomer, which is why it is called entropic elasticity.