Abstract: A bend stiffener comprises a (i) a flexible polymeric sleeve having an axial bore for receiving an elongated flexible member and (ii) attachment means for attaching the sleeve to a support. At least a portion of the flexible polymeric sleeve is a polyurethane elastomer produced in a reaction of an isocyanate-terminated prepolymer and a curing agent at an isocyanate index of 90 to 120. The isocyanate-terminated prepolymer has an isocyanate content of 7 to 15% by weight and is a reaction product of at least one aromatic polyisocyanate and at least one polyether polyol having a hydroxyl equivalent weight of 350 to 2000 and a nominal functionality of 2 to 2.3. The curing agent is one or more chain extenders having an equivalent weight per isocyanate-reactive group of up to 125 or a mixture of one or more such chain extenders and one or more polyether polyols having a hydroxyl equivalent weight of 350 to 2000 and a nominal functionality of 2 to 2.3.

Abstract: A bend stiffener comprises a (i) a flexible polymeric sleeve having an axial bore for receiving an elongated flexible member and (ii) attachment means for attaching the sleeve to a support. At least a portion of the flexible polymeric sleeve is a poly-urethane elastomer produced in a reaction of an isocyanate- terminated prepolymer and a curing agent at an isocyanate index of 90 to 120. The isocyanate-terminated prepolymer has an isocyanate content of 7 to 15% by weight and is a reaction product of at least one aromatic polyisocyanate and at least one polyether polyol having a hydroxyl equivalent weight of 350 to 2000 and a nominal functionality of 2 to 2.3. The curing agent is one or more chain extenders having an equivalent weight per isocyanate-reactive group of up to 125 or a mixture of one or more such chain extenders and one or more polyether polyols having a hydroxyl equivalent weight of 350 to 2000 and a nominal functionality of 2 to 2.3.

Abstract: A polyurethane elastomer showing desirable conductivity properties comprises at least 0.3 percent by weight of an aggregated particulate carbon black, having a particle size of less than or equal to 100 nanometers, that forms a continuous conductive pathway within the polyurethane elastomer. The polyurethane elastomer may exhibit a surface resistivity ranging from 1×104 to 1×108 ohms. It may be made by first preparing an isocyanate-terminated prepolymer containing the carbon black, the prepolymer having a volume resistivity of from 1×104 to 1×108 ohms, and then reacting the isocyanate-terminated prepolymer with an isocyanate-reactive component. The proportion of the prepolymer ensures that it forms a continuous phase in the final elastomer.