Hydrolysis of Kevlar Fibres

Kevlar fibres were hydrolyzed in a concentrated aqueous solution of either sulphuric acid or sodium hydroxide. The hydrolyzed fibres were characterized by measuring the tensile strength and the interlaminar shear strength (ILSS). The active sites on the hydrolyzed surface were determined by the dyeing-decolorizing method. The tensile strength of the hydrolyzed fibres decreased with an increase in hydrolysis time and showed a turning point. The alkaline hydrolysis improved the ILSS by about 4%, while acid hydrolysis showed insignificant improvement. From the experimental results, the better hydrolyzing condition is by treating the fibres in 10 M NaOH at 100°C for 5 h.