Examples are electrostrictive polymers and dielectric elastomers. Synthetic adhesives are based on elastomers, thermoplastics, emulsions, and thermosets. Liquid crystalline elastomers (LCEs) are slightly crosslinked liquid crystalline polymer networks. Fluoroelastomers are more expensive than neoprene or nitrile rubber elastomers. Most industrial chemical milling facilities use maskants based upon neoprene elastomers or isobutylene-isoprene copolymers. Examples of thermoplastic olefin elastomers (TPO) compound are For-Tec E or Engage. Silicones and acrylic elastomers are other alternatives. Handbook of Condensation Thermoplastic Elastomers, edited by. These materials were also used to produce rigid foams, gum rubber, and elastomers. This has been overcome by the use of hypo-allergenic synthetic elastomers such as silicone rubbers. Polyethers are the most hydrophilic impression material of the hydrophobic elastomers. The behavior of unfilled, vulcanized elastomers often conforms closely to the hyperelastic ideal. Development of plastics and synthetic elastomers has led to greatly expanded scale of production. This makes silicone rubber one of the elastomers of choice in many extreme environments. Dielectric elastomers (DEs) are smart material systems that produce large strains.