ABSTRACT
There are many commercially available elastomers that are used in biomedical applications, generally in in vitro situations. As could be expected, the lower cost of commercial elastomers dictates that they be used whenever the special attributes of medical-grade elastomers is not required. Some of these elastomers include acrylic elastomers such as poly (ethylene methylmethacrylate), butadiene rubber, butyl rubber, along with brominated and chlorinated butyl rubbers, epichlorohydrin rubber, ethylene-propylene, ethylene-propylene-diene (EPDM), and other olefinic thermoplastic elastomers including chlorinated and chlorosulfonated polyethylene, ethylene vinylacetate (EVA), fluorocarbon rubbers such as vinylidene fluoride chlorotrifluoroethylene copolymer, natural rubber, nitrile rubber, polychloroprene, polyisoprene, polysulfide rubbers, plasticized polyvinyl chloride, silicone rubber, styrene-butadiene rubber (SBR), and urethane elastomers and copolymers.
The polyurethanes and silicone rubbers are the most common elastomers in use in medical settings, although medical grades of many of the commercial elastomers are also available. Much of the current biomedical elastomer research is focused on the causes of environmental stress cracking sometimes seen with the polyurethanes in applications such as cardiac pacemaker leads, and on the ways to make elastomers more compatible with blood, e.g., the worldwide race to achieve a successful 4 mm vascular graft.
