Abstract: An impact attenuator system includes a hyperelastic member that comprises an energy absorbing material which behaves in a rate-independent hyperelastic manner so that its permanent set is minimized and the material can absorb tremendous amounts of impact energy while remaining fully recoverable.

Abstract: An impact attenuator system includes a hyperelastic member that comprises an energy absorbing material which behaves in a rate-independent hyperelastic manner so that its permanent set is minimized and the material can absorb tremendous amounts of impact energy while remaining fully recoverable.

Abstract: This invention relates to novel light stable elastomers which exhibit good dynamic properties, and a process for their preparation. These elastomers comprise the reaction product of an isocyanate propolymer, a chain extender, and a catalyst selected from i) solid delayed action catalysts having a melting point of greater than about 60.degree. C., ii) alkyl substituted organotin catalysts containing alkylmercaptide ligands, and which are liquid at room temperature, and iii) alkyl substituted organotin catalysts containing sulfur bridging groups, and which are liquid at room temperature.