the purpose of this program was to develop soft composite materials to be used as fibers in the fabrication of maxillofacial prostheses elastomeric-shelled, liquid filled capsules having an average diameter of 2.3 mm have been developed as the composite system urethane shelled capsules containing polypropylene glycol are produced by an interfacial polymerization process in which a polyurea skin is instantly formed over the droplet and a polyurethane inner surface is developed at a slower rate. an automatic system was designed and built for producing the capsules. composites of the capsules in elastomeric polymers have a lower stiffness than that of the polymers. the capsules can produce composites as soft as foams if the binding polymers are kept to a minimum amount required for holding the system together