Elastomers for Biomedical Applications

Abstract

Abstract Over 11 percent of the gross national product of the U.S.A. is currently being spent in areas related to health care. Medical applications of polymers account for about six percent of the dollar sales of processed polymer products, or over three billion dollars annually. Medical devices, consumables, and their packaging are estimated to have used 2.3 billion pounds of polymers in 1992. This paper describes research and development within the biomedical elastomer and rubber segments of this market. Elastomers used in biomedical applications can be roughly divided into three groups; the commodity elastomers that happen to be used in the biomedical field, medical grades of elastomers that are certified for food contact or for short-term physiological contact, and a small group of elastomers that are suitable for longer-term physiological contact or implantation. Although significant from a national perspective, the many uses of commodity elastomers in the medical field will not be discussed in this paper. Some of the additional material requirements that occur when elastomers are employed in contact with biological systems include: more stringent quality control, higher purity, more controlled and cleaner manufacturing facilities, and much more additional paperwork—including information so that traceability is maintained. In most cases, the elastomers must have a degree of biocompatibility. Other specific features may also be needed, such as the ability to be sterilized by gamma irradiation or steam autoclave. Materials that are manufactured with these ends in mind are often called “medical grade.” The number of candidate materials for the high profile, implantable speciality elastomers market is considerably smaller. These elastomers must survive much more rigorous biocompatibility testing and are sometimes optimized for specific properties such as blood compatibility, extraordinary fatigue strength, or controlled biodegradability. Because there are relatively few rubbers or elastomers that are suitable for use in vivo, it is particularly significant that several of the most important of these have been withdrawn from the market because of perceived product liability issues.