Abstract
The work aims to modify the physical properties and structural parameters of Polyamide-6 fiber to be available for different applications through the annealing process. Polyamide-6 samples were annealed at every 10 degrees of temperatures ranging from 60 to 130 ??1??C when the time is constant (2 hours). The computer-aided two-beam polarizing interference microscope attached with variable wavelength interference filter (VAWI-technique) was used to achieve the optical measurements. The device was installed and calibrated using a software program to obtain a sharp two-beam interference pattern and sharp fringes inside the fiber. A CCD camera was used to transfer the microinterferograms to the image analysis screen to automatically measure the index of refraction and optical anisotropy of polyamide-6 fibers before and after the annealing process. To detect the improvements of the fiber structure, the oscillation and dispersion energies, dielectric constant, orientation factor, density, and crystallinity degree were calculated. The results shed light on the structural improvements of Polyamide-6 fibers on the molecular level.