Polyurethane Elastomers in Medicine

In this field PUs seek to replace silicone rubber, plasticized PVC, polyethylene, PTFE, polyester and nylon. As a class, PUs have been found to be relatively biocompatible materials. Originally polyesters were used but now, due to hydrolysis problems, polyethers predominate. Various commercial PUs have been made available and are given later. 

Materials implanted in body tissue nearly always generate acute local inflammation and repair mechanisms and three types of foreign body repair responses are observed. Physical property responses are encapsulation of the implant with a thin layer of surface lining cells (epithelial cells) 

Basic Properties—e.g. chemical structure (spectral identification, metals presence, molecular weight, additives and extractables). 

Hardness, tensile strength, elongation at break, modulus, compression set, thermal, electrical, optical properties. 

In Vitro Ageing—ageing in an artificial extracellular fluid for long time-periods at body temperature, 37°C. Ageing at elevated temperatures, for short intervals, in artificial extracellular fluids. 

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Szycher, M., A.A. Siciliano, and A.M. Reed, Polyurethane elastomers in medicine, in S, Dimitriu, Polymeric Biomaterials. New York Marcel Dekker, 1994, pp. 233-244. 

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