The moisture loading characteristics of two Kevlar fibers (49 and 149), two aramid copolymer fibers (X-500 and Technora), and two polybenzimidazole fibers (unmodified and sulfonated forms) were studied as a function of relative humidity (11-97% RH) by TG. The limited literature data on moisture absorption in these high-tech fibers infer a linear dependence of absorbed moisture versus %RH. Our results suggest a nonlinear, sigmoidal dependence on %RH. The temperature of maximum rate moisture loss varied from 75-110 ° C, implying that polymer physical packing and chemical structure, including impurities, play a significant role in the amount of moisture absorbed and the degree to which it is bound. © 1990.
Keinath, S. E., & Morgan, R. J. (1990). Moisture content of aramid and polybenzimidazole fibers. Thermochimica Acta, 166(C), 17–26. https://doi.org/10.1016/0040-6031(90)80166-V