Load Induced X-Ray Line Broadening in Nylon Filaments

Abstract

The load induced microscopic structural changes in highly oriented Nylon filaments were followed by changes in the x-ray fiber diffraction pattern as a function of the resulting strain. Observations made included (1) changes in the dimensions of the fiber spots, and (2) a decrease in ratio of the intensity of amorphous to crystalline x-ray scattering. These new results for Type 200 du Pont Nylon indicate a change in the micro deformation mechanism at a strain corresponding to the inflection of the load-strain diagram (14 percent elongation). The mechanism for smaller plastic strains appears to involve a rotation of the crystallized domains into alignment with the fiber axis, accompanied by a small over-all additional crystallization. For strains larger than the inflectional strain, the mechanism seems to involve a progressive reduction in the domain size, and a reduction in alignment with the fiber axis. Both effects appear to saturate in the vicinity of the rupture strain. These results are discussed in terms of load induced effects found in metal single and polycrystals. It is suggested that the qualitative features observed may be representative of a wide class of load or strain induced micro deformation reactions in the solid state.

The dynamic modulus of elasticity of regenerated cellulose fibres in relation to large deformation

“…In the light of our reasoning, rupture would occur mainly due to the failure of secondary valence bounds to re-establish lateral order. The occurrence of a range of extension with decreasing lateral order, leading to break, has been established by K auf f man and G e 0 r g e 14) by means of X-ray diffraction measurements on nylon monofilaments: it seems probable that the same phenomenon occurs in regenerated cellulose fibres. In our opinion the second yield range, leading to break, is only reached by fibres free of mechanical injury or intemal flaws (e.g.…”

“…In the literature several different experimental methods of approach lead to an understanding of the molecular processes, underlying the changes of polymer fibres caused by deformation. To mention some which have a direct bearing on our own investigation: stress-strain characteristics and fibre anisotropy (R 0 s e and G r iff i t h s 8)); creep and recovery measurements (P res s 12)); X-ray diffraction analysis (K auf f man and G e 0 r g e 14)); and as a comparatively recent method, the measurement of the dynamic modulus of elasticity (B a l l 0 u and Smith 4 ), Work 16 ), Hillier and Kolsk y 6)).…”

Tensile Recovery Behavior of Textile Fibers

“…It is known that other cold-drawn materials, such as metals, show local displacement of atoms and formation of internal spaces, observable by the fuzziness of the x-ray pattern. Similar &dquo;destruction&dquo; of the crystal lattice during the stretching process was recently described [24] for nylon 300, when the yield point was exceeded (at an elongation of approximately 15%).…”

Review of Textile Research and Development During 1950

“…The internal structure of polyamides has been studied with x-rays and the polarizing microscope by Gabler [423], and by Kordes and coworkers [440]. In a study by Kauffman and George [429] the change of x-ray structure with application of load was measured in an attempt to explain the unusual mechanical properties of these fibers.…”