Fatigue Behavior of Aramid Nonwoven Fabrics Under Hot-Press Conditions

Abstract

Tensile and compressive behaviors of aramid and polyamide nonwoven fabrics are studied under hot-press fatigue conditions. Tensile breaking strength and the maximum modulus of tensile strength-elongation curves for the polyamide nonwovens gradually decrease with increasing fatigue after around 15 cycles, while those of the aramid nonwovens substantially increase. Aramid nonwoven values are about three to five times those of the polyamide nonwovens. These fatigue behaviors result from the differences in heat resistance and mechanical properties of polyamide and aramid fibers, indicating that polyamide fibers greatly deteriorate with heat while aramid fibers deteriorate only a little. Although we have assumed that the aramid nonwoven fabrics compact their fiber assemblies under increasing cycles, there are no substantial dif ferences in the compressive behaviors of polyamide and aramid nonwovens.