Characterization of amorphous orientation of poly(glycolide-co-L-lactide) fiber by sonic velocity

The amorphous orientation of poly(glycolide-co-L-lactide) fiber with 90:10 mole ratio of glycolide to L-lactide(PGLA910) was studied by differential scanning calorimeter(DSC),wide angle X-ray diffraction(WAXD) and the sonic velocity method.The crystallization in PGLA910 came only from PGA according to the DSC and WAXD results of the drawn and annealed fiber.The sonic modulus was computed through determining the sonic velocity of PGLA910 fiber with crystallinity from about 5% to 30%,and the intrinsic transverse modul in the amorphous region and the crystalline region were E~0_(t,c)=(9.35 GPa) and E~0_(t,am)=(3.21 GPa) respectively obtained based on the two-phase model.The amorphous orientations of 7 drawn PGLA fibers had a linear relationship with the thermo-shrinkages and indicated the characterization was reasonable.