چكيده لاتين :
Monofilaments precursor of linear ultra-high molecular weight polyethylene
(UHMWPE) were produced by gel spinning at controlled conditions. The rheological
behaviour of UHMWPE solution (gel) was studied in paraffin oil at
175°C with deformation rates in the range 600-11000 S·1 which was in good agreement
with power law model. The effect of paraffin concentration of the extraction bath
was determined on the amount of paraffin remained in the precursor fibre and on the
extraction time. The desorption behaviour of paraffin/UHMWPE system is in accordance
with Flory-Huggins model. The precursor fibre structure and its morphology
before drawing process is a determining parameter in drawability and properties of the
produced fibre. Thus, the effects of processing conditions such as spinning speed,
spinneret geometry, and temperature of the region between the die and the quench
bath were investigated on the crystallinity of the precursor fibre. High deformation
rates (y a ) caused by decreasing the die diameter or increasinq the spinning speed
result in more macromolecular orientation- and increased degree of crystalHnity.
Significant recrystallization or crystal perfection took place during the solvent extraction
step which increased the melting point of the precursorfibre from 11S,SOC to 147°C.
