Polymeric Materials

Thermoset Polymers:

• Polyurethane (PU): PUs are generally available in the form of foams. Their major usage is in the form of crash protection and passive damping of vibrating structures. Their modulus of elasticity and strength are quite low (E<0.1 GPa and σ_f <50 MPa). However their loss coefficient is quite high (about 0.8), hence it is considered as one of the most superior materials for energy dissipation.
  
  
• Epoxy: Epoxy is an widely used thermosetting material in mechanical joints. It has an elastic modulus in the range of 2.3-3 GPa and strength between 35-70 MPa. Epoxy is often used as matrix to develop Glass fibre reinforced and Carbon fibre reinforced plastics.

Elastomers:

• Butyl Rubbers: Elastomers like foams find their major usage as crash protective material – since they can undergo very high strain without failure. Butyl rubbers have good resistance to abrasion and tearing, also they can work up to a temperature as high as 150⁰C. Their major usage include tubes, belts and hosts.
  
  
• Silicone Rubber (PDMS): Silicones are developed replacing the Carbon by Silicon in the main chains of the methyl-links. This has enhanced their thermal stability (service temperature up to 300⁰C). Often silicone molding resins are reinforced with fillers like chopped strands to enhance their modulus of elasticity and strength. Typical usage include seals, gaskets, o-rings, food processing equipments etc.