: In the melt spinning of high molecular weight poly(ethylene terephthalate), spinline immediately below the spinning nozzle was heated by irradiating the CO 2 laser with the intention of controlling the physical and mechanical properties of resultant fibers. In comparison with the fibers prepared without the laser irradiation, as-spun fibers obtained with laser irradiation showed higher elongation at break and higher tenacity. Higher elongation was attributed to lower tensile stress in the spinline caused by the increase of spinline temperature. Drawn fibers were produced from thus prepared as-spun fibers at various draw ratios. When the drawn fibers with similar elongation at break were compared, fibers prepared with the laser irradiation showed steeper increase in the stress-strain curve in the region of low strain, and showed higher tenacity as a result. On the whole, plot of the relation between tenacity and elongation at break of each fiber shifted toward higher tenacity and higher elongation in case of fibers prepared with the laser irradiation, indicating that the toughness of the fibers were improved. Numerical simulation of the melt spinning process incorporating the effect of laser irradiation suggested that temperature increase by the laser irradiation was at most about 70 degree in the spinning conditions adopted in this study. It was also confirmed that the heating of the spinline immediately below the spinneret led to steeper decrease of spinline diameter in the region near the spinneret, and reduction of strain rate and decrease of tensile stress in the region of lowered spinline temperature. These changes in the thinning behavior of the spinline were speculated to be the origin of the changes in the mechanical properties of laser irradiated fibers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.