Opto-thermal properties of fibres - 4. Correlation of the density and loss tangent change with some physical parameters of annealed nylon-6 fibres

Nylon-6 fibres were annealed at various temperatures (90-175 degrees C) for time intervals from 1 to 10 hours. An acoustic method has been used for measuring the density and the mechanical loss factor of these fibres. The variation of refractive indices and birefringences of nylon-6 fibres was studied by two interferometric techniques: the multiple-beam interferometric method in transmission and the two-beam method by using the Pluta polarizing interference microscope. The X-ray diffraction technique was used to interpret the variations in optical and mechanical parameters obtained due to thermal treatments. Relations between the! optical data, mechanical loss factor and density with different annealing conditions are given for these fibres. Illustrations are given using graphs and microinterferograms. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.