Development of macrostructural effects of cold drawing on nylon 6 fibers

Abstract

This work reports measurement of the molecular orientation by two techniques for nylon 6 fibers drawn at room temperature. The changes in the strain and optical parameters are used to obtain some macrostructural parameters to evaluate the cold-drawing process values of the mechanical orientation functions, [P 2 (cos )], [P 4 (cos )], amorphous and crystalline orientation functions (F c and F a ), and the molar number of chain segments per unit volume (N e ). Also the crosslink density (N 0 ), the chain entanglement density (N s ), the average optical orientation F av , the dielectric constant (), the dielectric susceptibility (), the shrinkage stress (k s ), and other parameters were calculated. Relationships between the calculated parameters are given. The present study demonstrates changes in the molecular reorientation factors and the obtained new physical properties resulting from cold-drawing process.

Nanostructural modifications of polyamide/MMT hybrids under isothermal and nonisothermal elongational flow

“…Moreover, it is predictable that at each system composition the drawing slightly increases the polymer orientation along the stretching direction 33. Correspondingly, a reduction in the overall crystallinity can be observed, as judged from the gradual weakening of the scattering with increasing strain.…”

“…This finding may be related to the occurrence of order → disorder transitions upon deformation. On this point, it should be underlined that in the course of a drawing process the crystallinity of semicrystalline polymers, such as polyamides, can increase or decrease depending on several factors: the drawing conditions (draw ratio, draw rate, and temperature), the starting structure and the chemical nature and composition of the polymeric system 33–38. In particular, metastable phases are commonly found in the melt‐spun polyamide fibers above the so‐called Brill transition (occurring in the temperature range of 120–180 °C) as a result of the quenching of the molecular moieties during the crystallization process that freezes the material structure in a transient state of order during the transformation from a melt to a solid state 39…”

Birefringence and orientation parameters of cold‐drawn viscose fibers

“…These parameters with their relations to the mechanical parameters were given recently extensively elsewhere. 2,6,8…”

“…1 Intensive interferometric investigations have been carried out by many authors to study, improve, and develop various characteristics for investigations in fibrous materials. [2][3][4][5][6] A several number of investigations have been devoted to the physical properties of viscose fibers, including mechanical ones such as elastic modules, yield strength, elastic shear modules, and compressibility, which indicate how particular materials react when stressed. There properties can be employed to seek an explanation of the observed macroscopic behavior of the material in molecular term, which include details of the chemical composition and physical structure.…”

Influence of Hot Multistage Drawing on Structure and Mechanical Properties of Nylon 6 Multifilament Yarn

“…For apparel and carpet end-uses the nylon yarns are cold drawn, while in high tenacity industrial applications for tire cords and uses such as car seat belts, the yarns are drawn in hot multistage [11,12]. The effect of drawing on the structure and molecular orientation of nylon 6 fiber has been investigated by several researchers [3][4][5][13][14][15][16][17][18][19][20][21][22][23]. Microstructural changes that occur during drawing of nylon 6 fiber are usually characterized by various physical methods such as X-ray diffraction, differential scanning calorimetry (DSC), solid state NMR, polarized FTIR, density measurement, and optical microscope.…”