Opto-mechanical properties of fibres. Part 1. Optical properties and orientation of drawn polyethylene fibres

Abstract

Changes in the structure of different drawn polyethylene (PE) fibres are studied by the Becke' line method and interferometrically. The Becke' line method is used to study the changes in the optical properties of the skin layer of PE undrawn fibres. A Pluta polarizing interference microscope is used to determine the mean refractive indices and mean birefringence of the drawn fibres. Some structural parameters, such as optical orientation function, electric polarizability difference and isotropic polarizability (Δα/3α0), are determined. This last parameter is found to be constant and depends only on the fibre structure. The number of molecules per unit volume and the distribution of segments at an angle with respect to the draw ratio are also determined. The generalized Lorentz–Lorenz equation given by de Vries is used to determine PE fibre structural parameters. A comparison between the experimental and those obtained using the Lorentz–Lorenz equation is given. A refractive index profile can assist fibre characterization. An empirical formula is suggested to correlate the changes in A, Δn, fθ and θ with the draw ratio, and its constants are determined. Microinterferograms and curves are given for illustration. © 1999 Society of Chemical Industry

Semi-Grand Canonical Monte Carlo (SGMC) Simulations to Interpret Experimental Data on Processed Polymer Melts and Glasses

“…It is this wealth of microscopic-level information that justifies the more intense computational expense of an SGMC simulation. We demonstrate this method for a variety of systems that span the range of orientation observed in experimental polyethylene melt studies [9][10][11] as well as higher orientations that have been simulated for polyethylene melts by molecular dynamics. 12,13…”

Changes in orientation caused by UV irradiation of nylon 6 fibers

“…(1), (2), and (3). Also, the change in the optical parameters may be due to alterations in the electrical properties arising from the existing space charges and the residual electric field in the fibers after preparation 42…”

“…Also, the change in the optical parameters may be due to alterations in the electrical properties arising from the existing space charges and the residual electric field in the fibers after preparation. 42 The form birefringence is usually neglected. It is evident that the birefringence yields reliable information about the orientation in single-phase systems, but additional information is required when two-phase systems are involved.…”

A modified formula for accurate determination of three‐dimensional birefringence of fiber using modified subfringe integration method

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