Chemical modification of Kevlar fiber surfaces and of model diamides



Organic reactions of aromatic diamides as models for PPTA fibers have been investigated to select reagents and conditions suitable for surface-controlled heterogeneous reactions on Kevlar filaments and fabrics. Amine functional groups have been incorporated into fiber surfaces by bromination followed by ammonolysis and by nitration followed by reduction. Modification of filaments has been attained without impairment of fiber properties. Preliminary experiments have also shown that the presence of amino groups on Kevlar fabric can provide remarkably improved peel strength and apparent interlaminar shear strength in epoxy laminates, suggesting a significant role of covalent bonding in improving adhesion in aramidepoxy composites.