Structure and Properties of Viscose Fibers due to Cold Drawing

Self Cite

This work throws light to study the changes of optical birefringence for cold drawn high density polyethylene (HDPE) thin film at different stresses. A stress–strain device connected to a scattering optical system was used to investigate the dynamical behavior of opto‐mechanical properties at room temperature (27°C ± 1°C). Some structural parameters, optical and mechanical orientation factors, f(θ), f2(θ), f4(θ), f6(θ), Fav, P2(θ), P4(θ), fc, and fm, were calculated. Also, the distribution segments at an angle (θ), the number of random links per chain (N1), the number of chains per unit volume (Nc), and the average work per chain W′ were calculated. The average value of the maximum birefringence was evaluated. The obtained studies demonstrate changes to the molecular orientation functions and evaluated micro structural parameters as a result of the applied cold‐drawing process on (HDPE) thin film. Relationships between the calculated parameters and draw ratios were presented for illustration. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Section: Introductionmentioning

confidence: 99%

Structure characterization of cold drawn high density polyethylene thin film

Fouda

El‐Tonsy

Seisa

et al. 2011

Self Cite

“…In the creep process, the changes in the optical properties can be determined by interferometric methods 4, 5. Interferometrics studies the optical anisotropy in some synthetic fibers as a function of the draw ratio 6–10. The study of optical anisotropy in polymer fibers material plays an important role in the knowledge of the molecular arrangement within the fibers.…”

Section: Introductionmentioning

confidence: 99%

Effect of creep strain on the optomechanical properties and some structural properties of terylene fibers

Seisa

2009

This article sheds light on the effect of creep strain [e(t); %] on the optomechanical properties and some structure properties of terylene fibers at several constant applied loads. Automated multiple-beam Fizeau fringes in transmission were used with a mechanical creep device attached to a wedge interferometer where the fiber was subjected to a constant load. This technique was used to determine the mean refractive indices and the mean birefringence values of terylene fibers under different conditions of e(t). The obtained optical results were used to evaluate the optical orientation function, optical stress coefficient, density, crystallinity, and mean-square density fluctuation with e(t). The obtained results show that, under a constant load, the terylene fibers extended with time, the rate of which decreased with time. An empirical formula is suggested to represent the variation of e(t) of terylene fibers with time, and the constants of this formula were determined. A mechanical model is proposed to represent e(t) of terylene fibers, which consists of two Kelvin elements combined in series, which were used to provide an accurate fit to the experimental creep curve. The stressstrain curve via creep was studied to determine some mechanical parameters of the investigated fibers: Young's modulus, yield stress, and yield strain. Illustrations with microinterferograms, graphs, and tables are given.

Some parameter characteristics of thermally treated viscose fibers

Fouda¹,

Oraby²,

Seisa³

2010

Self Cite

This article sheds light on some structural changes in thermally treated viscose fibers at a constant temperature of 100 6 1 C at different time periods. The obtained optical parameters were used to calculate the crystallinity, density, Herman's orientation function, average orientation, and form birefringence. In addition, the stress optical coefficients, thermal stress, molar refractivity, specific refractivity, and polarizabilities along and across the axis and segment anisotropy were obtained. Measurements of the refractive indices helped us to calculate the dielectric constant, dielectric susceptibility, surface reflectivity, and transparency transmittances. The mechanisms of structural variation for the viscose fibers due to the annealing process were examined with the structural details for optothermal parameters. The relationships between the measured and calculated parameters are given in illustrations and curves.