Ancient fiber products were remained on archaeological metal objects such as a sword and personal ornaments. These fiber products were the very precious document which then fiber product manufacturing technique can estimate, but fiber received the rust which occurred to metal objects, and they were changed from the real quality. We tried to confirm the mechanism of deterioration for fiber on metal objects. We reproduced silk (non-refinement fiber) textile bags (4cmx4cm) because of covering with standard plate of copper (JIS : C1100P) / iron (JIS : SS400) and investigated the influence that rust generated to metal gave silk fiber. After covering metal plate with silk bag, these
were spotted chemical reagent (NaCl and Na2SO4 3wt% aqueous solution) and were revealed in constant (25 degrees
Celsius / RH90%) for 12weeks and it caused metal corrosion state in 3weeks. I confirmed change in deterioration of silk
fiber used OM / SEM observation and X-ray analysis. The changes for color parts (light green or brown) of silk bags
were seen and not only metal corrosion but also Calcium products were confirmed on silk fiber using X-ray analysis.
There were estimated that the beginning of deterioration is reaction of metal ion and anion and second step were
reaction of Calcium ion from silk sericin and anion.
Melt spinning of poly(ethylene terephthalate) with intrinsic viscosity of 1.0 dl/g was carried out to
investigate the effect of the spinning nozzle diameter on characteristics of as-spun fibers. In general, tensile strength increased and elongation at break decreased with an increase in the take-up velocity. With the decrease of the nozzle diameter, such correlation in the elongation versus strength plot shifted to the upper-right direction. This result indicated the improvement of toughness. Network draw ratio of as-spun fibers prepared at different take-up velocities was analyzed through the matching of the true-stress versus true-strain curves by shifting the curves along the true-strain axis to create a master curve. The starting point of the strain hardening in the master curve shifted to lower strain with the decrease of nozzle diameter. From the linear relation between the obtained network draw ratio and thermal shrinkage stress, entanglement density was estimated based on the rubber-elasticity theory. The entanglement density was found to
increase significantly with a decrease in the nozzle diameter. Numerical simulation of the melt spinning process
suggested the decreases of the maximum tensile strain rate and the Deborah number in the spinning line with the
decrease of nozzle diameter. There is a significant decrease of the draw-down ratio as well. It was speculated that these factors play a dominant role for the variation of the state of entanglement and network draw ratio in the as-spun fibers. Continuous two-step drawing of the as-spun fibers revealed that the improvement of toughness in the as-spun fibers prepared using a small-diameter nozzle can be maintained in the drawn fibers.