Synthesis and Ballistic Evaluation of Selected Transparent Polyurethane Block Copolymers, Part II. Further Changes in Formulation
ARMY MATERIALS AND MECHANICS RESEARCH CENTER WATERTOWN MA
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In an extension of previous work on polyurethane block copolymers for transparent armor applications, several additional variations of the basic 2,4- toluene diisocyanatepolytetramethylene oxide1,4-butanediol formulation have been investigated. It has been found that excess diisocyanate in a given formulation improves ballistic resistance and that decreasing the amount of polyether soft segment has the same effect. More generally, it has been found that increased sample hardness Shore D parallels improved ballistic performance. High-speed photographic data have shown that these materials continue to absorb large amounts of ballistic energy, with relatively little of this energy manifested as fragment kinetic energy. A technique for the preparation of void-free ballistic test specimens involving the use of a polytetrafluoroethylene mold is also described.
- Polymer Chemistry