Elastomeriskt

Elastomeriskt (elastomeric) describes a property of materials that are highly elastic and can be stretched by large strains and recover their original shape when the stress is removed. Elastomeric materials are viscoelastic, combining elastic recovery with time-dependent viscous flow. They typically exhibit a low stiffness and high elongation compared with rigid polymers.

The characteristic feature of elastomers is a three-dimensional polymer network of crosslinked chains that restricts permanent deformation. When stretched, the chains become more oriented, producing restoring forces as entropy increases; upon release, the network contracts and returns to its initial state. The glass transition temperature (Tg) is well below room temperature for most elastomers.

Common elastomers include natural rubber (polyisoprene) and synthetic varieties such as styrene–butadiene rubber, polybutadiene, nitrile rubber (NBR), neoprene, silicone and polyurethane elastomers. Some are thermosetting, vulcanized rubbers; others are thermoplastic elastomers that can be melted and reformed.

Typical properties described for elastomeric materials are high elongation at break, low modulus, good damping, and variable chemical resistance. Their performance depends strongly on temperature, strain rate, and aging due to oxidation, ozone, and UV exposure, which can cause cracking or hardening over time.

Applications include seals and gaskets, tires, vibration isolation, flexible hoses, medical devices, and consumer products that require elastic recovery and durable deformation.