MECHANICAL-BEHAVIOR OF RESPIRABLE FIBRILS OF KEVLAR ARAMID FIBER, GLASS, AND ASBESTOS

The deformation of equivalent size and shape glass, asbestos and Kevlar* aramid fibrils, when subjected to bending or longitudinal compressive loads, was estimated based on published mechanical property data and established mechanical analysis. Based on this analysis, Kevlar fibrils are expected to deform more easily than glass or asbestos fibrils. This behavior is a direct result of the lower compressive modulus and compressive yield strength of Kevlar fibres. Among the Kevlar fibres studied, those with higher molecular orientation and crystalline perfection (Kevlar 149 > Kevlar 49 > Kevlar 29) were more flexible and deformed more easily. Compressive yielding may occur more easily in fibrils stripped from the spun filament surface and also may promote fibril breakdown through chemical degradation.