Structural development and residual stresses in thick filaments

Orientation distribution and residual stresses are well known problems in fabricated polymeric parts. However, little concentrated effort has been made in this field. In this thesis, the study of orientation development and residual stress in thick melt spun filaments are reported. The influence of processing conditions on characteristics of orientation and thermal quenched stresses in melt spun fiber are emphasized.

The relationships between stress and birefringence were obtained. Amorphous and crystalline materials were both considered and interpretation carried out using Hermans' orientation factors. Birefringence distributions were measured by the wedge method. Predictions of birefringence distribution was carried out and then comparison was made between theoretical and experimental results.

Estimation of thermal quench stresses in melt spun fibers was attempted and results are interpreted. Fibrillation was observed in the melt spun fiber of glassy polymer. SEM and small-angle x-ray diffraction were used to characterize.

Special characterization efforts were made on polycarbonate fiber as well as polycarbonate film using DSC. A small amount of crystal 1inity was suspected in melt spun polycarbonate fiber. Several techniques were performed to crystallize the polycarbonate film and then characterize the degree of crystallinity in crystallized polycarbonate films.