Synthesis and Ballistic Evaluation of Selected Transparent Polyurethane Block Copolymers. Part III. Further Efforts to Optimize Ballistic Performance.

摘要

In a continuation of previous work with polyurethane block copolymers for transparent armor application, further variations have been investigated in stoichiometry and type of monomer with regard to their effects upon ballistic performance (V(50)) of the resultant copolymer. For the copolymer composed of 2,4-toluene diisocyanate, polytetramethylene oxide, and 1,4-butanediol, variations in the soft segment/hard segment ratio have led to the composition which gives the highest V(50) value in this series. Attempts have been made to improve the V(50) by replacement of 1,4-butanediol with N,N-bis(2-hydroxypropyl)aniline, the substitution of xylylene diisocyanate for 2,4-toluene diisocyanate, the use of a variety of molecular weights of polytetramethylene oxide, and the incorporation of trimethylolpropane as a crosslinking agent. Correlations have been made between composition, specimen hardness, ballistic failure mode, and V(50) for the polyurethane block copolymers made from these materials.