Abstract
Automated variable wavelength interference microscope was used to study the effect of annealing process on the physical properties of isotactic polypropylene fibers (4:1 draw ratio, 515 tex, Bolton UK). The isotactic polypropylene (iPP) fibers were annealed at temperatures ranging from 60°C to 140°C. The spectral dispersion curves of refractive indices and birefringence of iPP fibers were determined at different annealing temperatures. The resulting data were used to determine the optical orientation function, orientation angle, degree of crystallinity, and dispersion parameters of the annealed samples. The study indicates that, the measured birefringence, orientation function, and the dispersion of crystallinity of iPP fibers have been improved with the increasing of annealing temperature. POLYM. ENG. SCI., 59:35–41, 2019. © 2018 Society of Plastics Engineers