Mechanical properties and structure of the zone-drawn poly(L-lactic acid) fibers

The zone-drawing (ZD) method was applied three times to the melt-spun poly( L-lactic acid) (PLLA) fibers of low molecular weight (M-v = 13,100) at diff erent temperatures under various tensions. The mechanical properties and su perstructure of the ZD fibers were investigated. The resulting ZD-3 fiber h ad a draw ratio of 10.5, birefringence of 37.31 x 10(-3), and crystallinity of 37%, while an orientation factor of crystallites remarkably increased t o 0.985 by the ZD-1. The Young's modulus and tensile strength of the ZD-3 f iber respectively attained 9.1 GPa and 275 MPa, and the dynamic storage mod ulus was 10.4 GPa at room temperature. (C) 1999 John Wiley & Sons, Inc.