Y. Okamura et al., INFLUENCE OF DRAWING AND BEAT TREATMENT ON SURFACE FREE-ENERGIES OF POLYETHYLENE TEREPHTHALATE FIBERS, Colloid and polymer science, 274(7), 1996, pp. 628-633
The surface free energies of polyethylene terepthalate fibers with dif
ferent draw ratios were experimentally determined by contact angle mea
surements in n-alkane/water systems. The dispersive component of the s
urface free energy increased with increasing draw ratio, whereas the n
ondispersive one remained almost constant. After heat treatment, the d
ispersive surface free energy increased, but was reduced above 140 deg
rees C. The nondispersive component increased by heat treatment at 190
degrees C. The increases in the density and birefringence of the fibr
es due to the drawing and heat treatment suggested that the increase i
n the dispersive surface free energy was caused by the increase in the
atomic density at the fiber surface due to drawing and heat treatment
. ESCA results indicated that the increment in the nondispersive surfa
ce free energy due to heat treatment was caused by the addition of fun
ctional groups to the fiber surface due to heat treatment.