DESIGN, FABRICATION AND CHARACTERIZATION OF OPTIMUM FIBROUS STRUCTURES OF POLYBENZIMIDAZONE YARN.
Technical Report,01 Apr 1965,30 Apr 1966
CELANESE CORP OF AMERICA NEW YORK NEW YORK United States
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A limited study was made to characterize the effects of parametric variations in construction on the mechanical performance of various parachute items made from polybenzimidazole PBI yarns. The results indicate that most of the specifications originally written for nylon parachute components can be met with PBI if suitable modifications are made in construction to allow for the lower tenacity of PBI yarn. Strength translation efficiencies are good enough to permit prediction of breaking loads of structures with reasonable accuracy on the basis of one pound per 100 deniers of yarn used. Sufficient amounts of each required end item were made to permit complete laboratory characterization including testing at ambient, 350 F, 450 F, 700 F, 900 F, and 1000 F after exposures ranging from 0 to 200 hours. Only the threads and one fabric were tested over the specified range when it became apparent that finish modifications would be required before reliable results could be obtained from high temperature testing. An investigation was made of the high temperature resistance of available candidate finishes and finish components applied to PBI fabric and yarn by various methods. While no satisfactory material was found, some leads were developed which may be useful in further studies. The testing done on the threads and lightweight fabric showed that PBI yarn structures retain about 40 of their original strength after exposure at 700 F for two hours, even with an unsatisfactory finish.