An isocyanate-reactive component is disclosed that reacts with a liquid polyisocyanate or polyisocyanate prepolymer in the preparation of a polyurethane-polyurea polymer. In one embodiment, a polyisocyanate component is reacted with an isocyanate-reactive component. The polyisocyanate component has an NCO group content of about 3% to about 50% and an average functionality of about 2 to about 3. The isocyanate-reactive component includes from about 20% to about 90% by weight, based on 100% by weight of the isocyanate-reactive component, of at least one organic compound having a mercaptan functional moiety.