Biomaterial for in situ tissue repair

A curable polyurethane composition comprising a plurality of parts capable of being mixed at the time of use in order to provide a flowable composition and to initiate cure, the parts comprising:

• (1) a quasi-prepolymer component comprising the reaction product of one or more polyether polyols, one or more isocyanates, and one or more reactive hydrophobic additives, and (2) a curative component comprising one or more polyether polyols, one or more chain extenders, and one or more catalysts,
• wherein the composition is sufficiently flowable to permit it to be delivered to a tissue site by minimally invasive means and there undergo complete cure in situ under physiologically acceptable conditions in order to provide a biocompatible material,
• and wherein the hydrophobic additive(s) are selected from the group consisting of hydroxyl- or amine-terminated compounds selected from the group consisting of polybutadiene, polyisoprene, polyisobutylene, silicones, polyethylenepropylenediene, copolymers of butadiene with acryolnitrile, copolymers of butadiene with styrene, copolymers of isoprene with acrylonitrile, copolymers of isoprene with styrene, and mixtures thereof.