A Short Introduction About Thermoplastic Elastomers (TPEs)

What is Elastomers?

An Elastomer, a polymeric material and has an elongation greater than 100 percent and a considerableamount of resilience. In addition, the start of plastic deformation must be delayed for elastomers toexperience pretty large elastic deformations. Limiting the motions of chains past one another by cross-linking completes this objective. However, cross-linking in plenty of elastomers is performed in a processcalled vulcanization by heating with Sulphur about 140oC.

Classification of Elastomers

Natural Rubber (Thermoset by cross-linking) Synthetic Rubber (Thermoset by cross-linking), like Polyisoprene, Styrene Butadiene Rubber

(SBR), Chloroprene, Polybutadiene, Nitrile rubber, Butyle rubber, Silicones, Ethylene propylenediene monomer (EPDM) and many more.

Thermoplastic Elastomers

Thermoplastic Elastomers (TPEs)

TPEs is a special group of polymers that dont depend on cross-linking to make a great amount of elasticdeformation. Thermoplastic Elastomers have Rubber as well as thermoplastic characteristics. Inaddition, TPEs are flexible same like vulcanized rubbers and are melting processible like a thermoplastic.Several TPEs have a block copolymer structure that contains a soft thermoset polymer and rigidthermoplastic segments within the polymer chain. For example: butadiene rubber and copolymer ofpolystyrene.

Advantages of Thermoplastic elastomers (TPEs)

There is no chemical cross-linking Simple and easy processing with quicker cycle times Scrap and waste can be recycled. However, normal cross-linked polymers cannot be recycled as

they don't melt because of the cross-links tie all the polymer chains together, and making it notpossible for the material to flow.

It can be processed by Injection molding, thermoforming and extrusion, Blow molding With simple tooling, undercuts and multifaceted shapes are possible.

Limitations: Thermoplastic elastomers may have lower temperature resistance compared to mostthermoset rubbers. Besides, they are creep resistance inferior to thermoset rubbers.

Commercially available thermoplastic elastomers and their applications

Styrenic block copolymer- Polystyrene + Butadiene or polyisoprene

Applications: Razor handles, Medical devices, Grips on cameras, Shoe soles Adhesives

Reactor thermoplastic polyolefin- Polypropylene + EPDM rubber

Applications: Cable and wire jacketing, Automotive bumbers, Hydraulic engine mount heat shield.

Thermoplastic polyurethane- Polyester / polyether polyurethane + long chain diols

Applications: Seals / gaskets, Shoe soles, Conveyor belts, Automotive underhood applications, Caster / wheels.

Thermoplastic polyamide- Polyesteramide / polyetheramide + polyether polyol

Applications: Cable jacketing, Seals / gaskets, Tail light housing and High toughness athletic equipments

Thermoplastic copolyester- polybutylene terepthalate + Polytetramethylene ether

Applications: Hoses, Seals, Belting, Combustion air swirl generator, Caster / wheels.

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