elastomerscrosslinked

Elastomers are a class of polymers that exhibit viscoelasticity, meaning they have both viscosity and elasticity. Their defining characteristic is their ability to deform significantly under stress and return to their original shape upon removal of the stress. This remarkable property is achieved through a process known as crosslinking.

Crosslinking, also called vulcanization in the case of rubber, involves the formation of chemical bonds between adjacent polymer chains. These bonds create a three-dimensional network structure, preventing the polymer chains from permanently sliding past one another when stretched. Without crosslinking, many elastomers would behave more like viscous liquids, deforming permanently rather than elastically.

The degree of crosslinking significantly influences the mechanical properties of an elastomer. Higher crosslink densities generally lead to increased tensile strength, hardness, and resistance to swelling in solvents, but can also reduce elongation at break. Conversely, lower crosslink densities result in softer, more flexible materials that can stretch further.

Common crosslinking agents include sulfur for natural rubber and many synthetic rubbers, peroxides, and metal oxides. The choice of crosslinking agent and the conditions under which the crosslinking reaction occurs are crucial for tailoring the final properties of the elastomer for specific applications, ranging from tires and seals to medical devices and footwear.