On kink banding in individual PPTA fibres

Whilst having excellent tensile qualities, poly(p-phenylene terephthalamide) (PPTA) fibres perform poorly in compression often suffering from localized structural instabilities such as kink band deformation. A recent two-dimensional model for the initiation of kink bands in layered materials is adapted to examine the possibility of their appearance in PPTA fibres. Using models and experimental results from the literature, the crystalline and fibrillar structure, the elastic properties and the propensity for kink banding of the fibres are discussed. Ranges for the parameters for the kink band initiation model are then deduced and lead to predictions of band widths that compare favourably with those measured experimentally.