A study of the dynamically perturbed process of polymer melt spun filaments with interactive computer managed variables

This study was based on a fundamental concept concerning the fiber forming process suggested by Lindenmeyer (30) who treated it as a dissipative process where the structure formation depended upon both the nature of the fluctuation that initiates the process and the minimum dissipation of energy that determines its path. With this knowledge, computer manipulated optical instruments in conjunction with perturbing devices were used to study the character of these perturbing forces on the melt spinline.

In this study, the experiment was focused on the melt spinline of high density polyethylene (HDPE). By applying an interactive control device, an on-line real-time study of birefringence during the melt spinning was employed to investigate the effect of sound wave perturbation. Furthermore, off-line measurements were acquired over a range of spinning variables on the as-spun fiber to relate physical properties with the perturbing force. The final perturbed spun fibers were characterized with various techniques: birefringence, wide angle x-ray scattering (WAXS), differential scanning calorimetry (BSC), crystallinity, and tensile testing.

A significant change of birefringence under sound wave perturbation was observed on both the melt spinline and final spun fiber. Off-line characterizations of sound wave perturbed spun fibers seemed to indicate the amorphous region is predominately responsible for the change of birefringence. The crystalline region seemed to be independent of the sound wave driving force. The variation in the optical property measured as birefringence was a result of the internal response to sound wave perturbation, and was a function of amplitude and frequency.