Studies on the orientation phenomena by fiber formation from polymer melts. Part I. Preliminary investigations on polycapronamide

Abstract

The problem of the mechanism of macromolecule orientation occurring in the formation of fibers from polymer melts has been qualitatively analyzed. As a result of birefringence, x‐ray, and spinning stress investigations carried out on polycapronamide fibers, the main parameters determining orientation have been established. They are the parallel velocity gradient along the spinning length, G = dV/dl, and the relaxation factors. The deformation ratio S (the ratio of final to original linear velocity), analogous to the draw ratio λ = 1/10 in the cold‐drawing process, has no influence on the degree of orientation. The orientation by spinning is not accompanied by any such structural transformations as occur through cold‐drawing. The fibers spun at high velocity gradients consist of well‐oriented β‐polycapronamide. It is thus assumed that the orientation proceeds in the region of the liquid melt‐stream as a result of simultaneous action of velocity gradient and thermal relaxation. This mechanism, analogous to that causing the familiar streaming orientation of polymer solutions in capillaries or in a Couette apparatus, is different in principle from that of the cold‐drawing process.

Optical Effects in Flow

“…The observed birefringence and crystallization effects indicate an almost complete extension of macromolecular coils (Mackley & Keller 1973, 1975Keller & Mackley 1974). The observations on the spinning line of fibers (Ziabicki & Kedzierska 1959, Katayama et al 1973, Nagasawa et al 1973 are so strongly influenced by the rapid cooling and crystallization that no general conclusion is possible about the dependence of birefringence on gradient. However, the acoustical birefringence (Lucas 1938(Lucas , 1939 exhibits strict proportionality to the amplitude, i.e.…”

Uniaxial deformation of nylon-6 and nylon-11: changes in orientation and crystal phase

“…The γ phase can be obtained by treatment of nylon-6 with KI-I 2 (14), by annealing (15) or by melt spinning at very high speeds (16). This structure is a twisted or pleated-chain conformation, which exhibits a repeat distance shorter than that of the all-trans α phase.…”

Structural Characterization of Nylon 6/EvOH System Through Transport Properties

“…2, the WAXDs of all the investigated samples are shown. These phases have been variously identified as β [24][25][26], α paracrystalline [27,28] 2. This type of crystalline phase is present also in the blend with 10% EvOH (B), while the diffractograms of samples C and D are rather difficult to interpret.…”