MOLECULAR-ORIENTATION IN UNIAXIAL, ONE-WAY AND 2-WAY DRAWN POLY(VINYLCHLORIDE) FILMS

Uniaxially oriented poly(vinyl chloride) films drawn at 90, 100 and 11 0-degrees-C to draw ratios in the range 1.5-3.5 have been investigated using i.r. spectroscopy and refractive index measurements. Their 10 s isochronal extensional creep moduli and dynamic tensile moduli have a lso been measured. One-way drawn films with draw ratios in the range 1 .56 x 1 2.56 x 1 and simultaneously and sequentially two-way drawn fil ms with draw ratios in the range 1.46 x 1.46-1.79 x 1.79 have been inv estigated using refractive index measurements and i.r. spectroscopy. T hese films were drawn at 85 and 95-degrees-C. Thermal analysis of the drawn samples showed that the uniaxially drawn films were drawn at tem peratures well above their final glass transition temperatures, wherea s the one-way and two-way drawn films were drawn close to their glass transition temperatures. The results show that the crystallites are mo re highly oriented than the amorphous chains and that one-way drawn sa mples depart slightly from uniaxiality. No significant difference in o rientation was found between simultaneously and sequentially two-way d rawn samples. It was shown that the i.r. peak at 613 cm-1, attributed to short syndiotactic segments, could be used to characterize the orie ntation of the amorphous chains. The elastic moduli of the uniaxially drawn samples were found to depend on orientation in a similar way to that previously reported.