STUDIES ON BIODEGRADABLE POLY(HEXANO-6-LACTONE) FIBERS 1 - STRUCTURE AND PROPERTIES OF DRAWN POLY(HEXANO-6-LACTONE) FIBERS

Using high molecular weight (M-n=80,000) Poly(hexano-6-lactone) (PCL') , tough and high tenacity PCL monofilaments with various draw ratios ( undrawn to 9 times drawn) were prepared by melt-spinning. The relation ship between microstructure and properties of the PCL fibers is descri bed in this current IUPAC Technical Report. Analysis of microstructure of the drawn PCL fibers by wide-angle X-ray diffraction revealed typi cal c-axis orientation with an increase in crystallinity. It was also supported by sonic velocity measurements. The thermal, mechanical, and dynamic mechanical properties of the PCL fibers were affected signifi cantly by draw ratio. DSC thermograms showed that the melting temperat ure and the enthalpy of fusion increased with draw ratio. The temperat ure dependence curves of dynamic viscoelasticity showed that the tempe rature at tan delta peak of alpha dispersion corresponding to the glas s transition temperature shifted toward higher temperature and the pea k value of tan delta decreased with draw ratio. The dynamic storage mo dulus and the sonic modulus increased with draw ratio. These results a re due to the increase in crystallinity and molecular orientation with drawing, and are responsible for an increase in tensile tenacity as w ell as knot tenacity of the PCL fibers.