Effects of heat treatment on the mechanical properties of Kevlar-29 fibre

Thermal aging treatments under both atmosphere and vacuum environments at t emperatures of 100 degrees C to 300 degrees C for durations from 2 to 8 h h ave been made on Kevlar-29 yarns. The effects of thermal aging on tensile s trength, tensile strain and the Young's modulus of the single fibre have be en evaluated. It was established that both the tensile strength and the ten sile strain decreased with increase in treatment temperature. For treatment ;It constant temperature the heating duration did not appear to have any ef fect on the tensile strength and the tensile strain. It was also found that the Young's modulus of the single fibre was not affected by heat treatment under the conditions described above. Heat treatment in vacuum did not hav e any effect on the tensile strength. (C) 2000 Elsevier Science Ltd. All ri ghts reserved.