Poly(ethylene‐2,6‐naphthalenedicarboxylate) fiber for industrial applications

Abstract

SYNOPSISPoly(ethylene-2,6-naphthalenedicarboxylate)(PEN) has been prepared from commercial dimethyl-2,6-naphthalenedicarboxylate (DM-2,6-NDC) and ethylene glycol (EG) according to the well-known transesterification/polycondensation route. P E N fibers, intended for industrial yarn applications, were obtained by melt spinning and drawing high molecular weight PEN. The properties of these yarns were measured in detail and compared with those of P E T industrial yarns. The development of molecular orientation in the spinline is more pronounced for PEN than for PET. Because the yield stress is lower, P E N yarns can more easily be drawn. Breaking tenacities of PEN yarns are comparable with those of P E T yarns, but the modulus is much higher and the thermal shrinkage is lower. Therefore, P E N yarns have a better dimensional stability than PET yarns. In addition, it was demonstrated that the thermal resistance of P E N yarns is better. 0 1995 John Wiley & Sons, Inc.

Structure development and physical properties achieved in the drawing and/or annealing of PEN fibers

“…These features are somewhat different from those in other reports, where the as-spun fibers produced at similar speeds reveal broad or poorly resolved scattering peaks. 6,9,11 Through an examination of the relationship between the thread-line tension monitored by online measurement and the IV and crystallinity data for individual as-spun fibers, the discrepancy between our results and others has been attributed to the high spinning stress generated by the high molecular weight polymer used in our study. 12 When the 5 km/min as-spun fiber was subjected to heat setting at various temperatures, as shown in Figure 6(b), crystalline reflections of ␣ 010 and ␣ 100 at 2 ϭ 15.7 and 23.3°start to appear at relatively high temperatures, indicating that the content of the ␣-form crystal is promoted by the annealing temperature being increased.…”

“…Figure 10 shows the total DR as a function of the take-up velocity at which various precursor fibers were prepared, as derived from the literature 7,9 and this work. It is obvious that the total DR decreases as take-up velocity increases and approaches unity over 4 km/min.…”

“…Of the previously cited articles, however, only a few of them were concerned with the investigation of the structural changes in drawn and/or annealed PEN filaments. [7][8][9][10] In this study, as-spun PEN fibers (i.e., precursor samples) prepared at various take-up velocities were drawn and/or annealed. The effects of the as-spun structure, which was affected significantly by the spinning, drawing, and annealing conditions, on the structure and properties of the resultant fibers were studied by X-ray scattering, differential scanning calorimetry (DSC), and tensile measurements.…”

Mesophase structure discovered through in-situ X-ray measurement in drawing process of poly(ethylene 2,6-naphthalene dicarboxylate) fiber

“…And it has been reported that the ȕ-crystal was formed by high-speed spinning or by high-temperature annealing. [16,17] It is interesting that the ȕ-rich crystal was developed by laser drawing. In…”

Fiber structure formation in ultra-high-speed melt spinning of poly(ethylene 2,6-naphthalene dicarboxylate)

“…4 Huijts et al prepared high-speed spun PEN since the throughput rate was kept constant for all the take-up velocities. The intrinsic viscosity fibers and investigated the properties from the view point of industrial applications, 5 analyzed measured for the resultant fibers was 0.48 dL/ g. There was a relatively large reduction of the the mechanical behavior near the glass transition temperature, 6 and estimated the intrinsic biremolecular weight during the spinning experiment. The level of molecular weight of the exfringence.…”