Linear structure: The general structure of vulcanized rubber. Because of the large molecular weight and no external force, the macromolecular chain is in the shape of a random curve. When the external force, the removal of external forces, the entanglement of the coil changes, the molecular chain rebound, resulting in a strong recovery tendency, this is the origin of high elasticity of rubber.
Branched structure: The chain of rubber macromolecules are clustered together to form gels. Gel is detrimental to the performance and processing of rubber. In the refining of rubber, a variety of additives are often not into the gel zone, forming a local blank, not to form a reinforcement and cross-linking, become weak parts of the product.
Cross-linking structure: Linear molecules are connected to each other through the bridging of atoms or clusters of atoms to form a three-dimensional reticular structure. As the vulcanization process progresses, this structure is continuously strengthened. Thus, the free activity ability of the chain segment decreases, plasticity and elongation decreases, strength, elasticity and hardness rise, compression permanent deformation and swelling degree decrease.