Effect of the conditions of laser treatment on the thermal and strength indexes of polyacrylonitrile fibres

Abstract

The results of laser treatment of fibres are not only determined by the average laser energy flux density on the sample during treatment but also the irradiation regimen. In going from a continuous irradiation mode to a pulsed mode, the probability of accumulation of energy in chemical bonds increases, and this increases the probability of their breaking and is the cause of a decrease in the strength indexes of the fibres. The probability of destructive processes increases with a decrease in the duration of the pulse and correspondingly with an increase in the peak laser energy flux values and with an induced decrease in molecular mobility due to removal of heat from the processed fibres. Changing the conditions of laser treatment of fibres allows varying the thermal indexes of PAN fibres during pyrolysis.