DEPENDENCE OF MOLECULAR ORIENTATION
ON PROCESSING CONDITIONS
IN THE MELT SPINNING OF MONOFILAMENTS FIBRES OF
POLY(L-LACTIDE-RAN--CAPROLACTONE-RAN-GLYCOLIDE)
J.Siripitayananon, R.Molloy and N.Ruaiporn
Biomedical Polymers Research Unit, Department of Chemistry, Faculty of Science,
Chiang Mai University, 50200, Thailand.
G.R.Mitchell
Polymer Science Centre and Department of Physics, University of Reading,
Whiteknights, Reading RG6 6AF, UK.
A random terpolymer of poly(L-lactide-ran--caprolactone-ran-glycolide)with
a mole % composition of 74:15:11 was synthesized and monofilament fibres prepared
by a combination of melt-spinning and off-line hot drawing[1]. Wide-angle X-ray
scattering techniques showed that the as-spun fibre as fully amorphous, whereas hotdrawing induced a certain level of crystallisation involving small crystals with a
structure similar to the  phase of poly(L-lactide)[2]. A novel procedure was
developed using a spherical harmonic representation of the scattering data to separate
the scattering contributions of the crystalline and amorphous components[3]. This was
exploited to provide quantitative orientation parameters for both the amorphous and
crystalline phases. Hot drawing at lower temperatures approaching the glass transition
resulted in significant levels of preferred orientation in the amorphous component
whereas, drawing at higher temperatures resulted in higher alignment of the
crystalline component. These orientation parameters together with the levels of
crystallinity are used to explore the processing-structure-property relationships of the
monofilament fibres especially with a view to their potential use as surgical sutures.
[1] M. Srisa-ard, R. Molloy, N. Molloy, J. Siripitayananon and M. Sriyai, Polym. Int 2001;
50:8, 891-896.
[2] W.Hoogsteen,
A.R.Postema,
A.J.Pennings,
Macromolecules 1990; 23:2, 634-642.
[3] G.R. Mitchell, Polymer 1984; 25, 1562-1572.
G.ten
Brinke
and
P.Zugenmaier