Linear structure: Unvulcanized rubber general structure. As the molecular weight is very large, no external force, the macromolecular chain was random coil curve. When the external force, the removal of external force, the entanglement of the line group changes, the molecular chain rebound, resulting in a strong tendency to restore, this is the origin of the high elasticity of rubber.
Branched structure: Rubber macromolecular chain of the chain of aggregation, the formation of gel. Gel performance of rubber and processing are detrimental. In the rubber, all kinds of complexing agents often can not enter the gel zone, the formation of local blank, can not form reinforcing and cross-linking, a weak position of the product.
Crosslinking structure: A linear molecule is linked to each other by bridging atoms or clusters to form a three-dimensional network. With the curing process, this structure continues to strengthen. In this way, the free mobility of the segments decreases, plasticity and elongation decrease, strength, elasticity and hardness increase, compression set and swelling decrease.