Degradation of aramid fibres under alkaline and neutral conditions: Relations between chemical characteristics and mechanical properties
Résumé
Aramid fibres are high performance materials which have been used in various fields such as heat and cut protection, composites, rubber reinforcement, ropes and cables, fabrics (etc) and are today proposed in geotextiles for alkaline ground reinforcement, as well as in cables for marine applications for a few years. However, there is a lack of experience on the long-term behaviour of aramid fibres in wet and alkaline environments. Aging studies have therefore been performed on Twaron 1000 fibres under different conditions (sea water, deionised water, pH9 and pH11). Hydrolytic degradation has been evaluated by FTIR and viscosimetry measurements, which have been correlated with tensile tests measurements. The tensile strength follows a logarithmic evolution with aging time, whereas the modulus remains constant. A linear relation between the tensile strength and the reduced viscosity of hydrolytically-aged fibres has been highlighted. Aging indicators have been proposed which allow the hydrolytic degradation to be quantified.