Birefringence in amorphous polyethylene terephthalate fibers

Abstract

The advent of high speed spinning of PET fibers has brought on a higher degree of "frozen-in" orientation in quenched amorphous fibers. Since these fibers are amorphous by x ray, birefringence measurements have constituted, until recently, the only independent characterization method for determining the frozen-in orientation. The amorphous orientation function is then calculated from the well-known equation'

Measurement of amorphous orientation in poly(ethylene terephthalate) fibers by X-ray diffraction and its significance

“…1W70 and 1W90 orientation of the oriented component and the are high-modulus and high-tenacity fibers, and fraction of the oriented component in amorphous A330 is experimental version the recently intro-PET fibers. 3 Recently, Urbanczyk carried out a duced dimensionally stable fiber 1130. Some of similar analysis on PET and N6 fibers.…”

“…Because of these uncertainties in the commonly of the x-ray diffraction (XRD) methods to evaluate amorphous orientation. [2][3][4][5][6] It so happens that to completely describe the amorphous halo, one has istics on the properties (strength and dimensional to separate the amorphous scattering into unoristability) of the fibers. ented and oriented components.…”

Scattering techniques for structural analysis of biomaterials

“…15,16,27,35 It can be seen in the data in Fig. 2.12b and 2.12c that, unlike the intensity in the crystalline peaks, the baseline intensity of the amorphous halo is not zero.…”

“…This non-zero intensity can be interpreted as being due to unoriented amorphous segments in the specimen. [15][16][17]27 This calls for two parameters to characterize the amorphous orientation: one is the width of the peak as in the case of the crystalline peak that corresponds to the degree of orientation of the oriented amorphous region f oa . The other is the area of the oriented scattering peak that represents the fraction of the amorphous segments that are oriented, or fractional orientation, F oa.…”

“…It has been shown that amorphous components in polymers can be separated into isotropic (unoriented) and anisotropic (oriented) components. [15][16][17]27 Optical birefringence, spectroscopy (NMR and IR), and diffraction are commonly used to determine the amorphous orientation.…”