BINDER STUDY - VISUAL CAST FLARES

Abstract
Techniques and castable formulations were developed that produce luminous efficiencies between 42,000 and 45,000 candle-seconds/gram; no diameter effect was apparent in the range of 1.5 to 4.95 inches. The early experimental effort on the use of compounded polyesters and urethanes was discontinued in favor of the use of glycidyl methacrylate and similar vinyl monomers. This class of monomer gives the desired solvation of the perchlorate (with concomitant increase in viscosity of the binder for improved particle wetting) and a controlled exotherm in large diameter castings. Final physical properties are attained after 24-hour post-cure. The use of sodium perchlorate in lieu of the insoluble sodium nitrate yielded a casting slurry of lower viscosity at constant binder percentage; the use of sodium nitrate was therefore discontinued. The use of a trimodal distribution of magnesium improved casting ease at the 15 percent binder level. Early program effort concentrated on the use of kraft paper cases in order to simulate standard flare hardware. The recognized 'tunnel effect' reduced the luminance values obtained and masked differences attributable to the binder type and content. Composition efficiencies were then obtained on free standing grains, displacement cast and the cylindrical surfaces inhibited. The program demonstrated the feasibility of cast illuminating flares based on commercial materials.

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