Optical Orientation Function Research Articles

Effect of recycling on the optical, mechanical and structural properties of polypropylene fibers

The effect of recycling on polypropylene fibers is studied interferometrically. Optical parameters as the refractive index profiles, the optical orientation function and the molecular structure are determined using the Mach–Zehnder interferometer. Some tensile parameters as well as some structural parameters are obtained with the aid of an automated drawing device attached with the interferometer. A comparison between these parameters for the studied (virgin, recycled and virgin recycled 50/50 polypropylene) fibers is presented to show the effect of recycling on these parameters. The study is performed using a He–Ne laser source with 10mW output power when its intensity is reduced to a low level in order to avoid the effect of the high intensity of this laser on the studied fibers.

The influence of mechanical cold drawing and drawing velocity on the molecular structure of isotactic polypropylene fiber

AbstractThe main goal of this work study is to study the influence of mechanical cold drawing and drawing velocity on the molecular orientation and physical structure parameters of isotactic polypropylene, iPP, fibers. A Video Opto‐ Mechanical device (VOM) attached with automatic multiple‐beam interferometric technique was used to cold draw iPP fibers at different draw ratio and drawing velocity. The molecular structure of iPP fiber was characterized by measuring the refractive indices, birefringence, optical orientation function, orientation angle, the percentage of the volume fraction of amorphous and crystalline regions, density and the mean square density fluctuation. The obtained microinterferograms of multiple beam interference fringes were enhanced and the noises were removed by using Fourier transform method. The obtained contour lines were analyzed via a software program for fiber refractive index determination. The results show that the drawing velocity has a less effect than the draw ratio on the molecular structure of iPP fiber. The contour lines of microinterferograms are given for illustration. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Opto-thermo-mechanical Characterization for Polyester and Polyamide Surgical Sutures

Abstract This work studies the opto-thermo-mechanical properties of two different surgical sutures using interferometry. The polarizing Pluta interference microscope combined with opto-thermo-mechanical (OTM) device were used to study the effect of drawing on monofilament polyester (PET) and polyamide (PA) surgical sutures at room temperature. The variation of the refractive indices and the birefringence of both PET and PA sutures with different draw ratios were determined. The resulting data was used to calculate the optical orientation function and the average work per chain. The stress–strain curve was studied to estimate some mechanical parameters; yield stress, yield strain, Young's modulus and strain optical coefficient. The variations of the refractive the index profile were calculated for different draw ratios. In addition we studied the effect of temperature, during the drawing process, on monofilament PET suture. The obtained results provide important data for better characterization of suture materials.

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

AbstractThis article sheds light on the effect of creep strain [ϵ(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 ϵ(t). The obtained optical results were used to evaluate the optical orientation function, optical stress coefficient, density, crystallinity, and mean‐square density fluctuation with ϵ(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 ϵ(t) of terylene fibers with time, and the constants of this formula were determined. A mechanical model is proposed to represent ϵ(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 stress–strain 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. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Interferometric study of creep deformation and some structural properties of polypropylene fiber at three different temperatures

AbstractInfluence of temperature on creep deformation for polypropylene PP fiber under a constant load was studied interferometrically. The automated multiple‐beam Fizeau system in transmission was equipped with a mechanical creep device attached to a wedge interferometer. This system was used to determine the optical properties (n∥, n⟂, and Δn) of PP fiber during the creep process at constant loading with varying temperature. The creep compliance was drawn as a function of both time and temperature. An empirical formula was suggested to describe the creep compliance curves for PP fibers and the constants of this formula were determined. Two Kelvin elements combined in series were used to provide an accurate fit to the experimental compliance curves. The stress–strain curve via creep was studied to determine some mechanical parameter of PP fibers, Young's modulus E, yield stress σy, and yield strain εy. The optical orientation function f(θ), the dielectric constant d, the dielectric susceptibility χ, the surface reflectivity $ \overline R $, and the average work per chain W′ were also calculated. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Study of Optical and Structure Properties of Polyester (PET) and Copolyester (PETG) Fibers by Interferometry

In this article results on the influence of drawing on the optical and structure properties of polyester (polyethylene terephthalate) and copolyester (glycol-modified polyethylene terephthalate) (4 wt% of ethylene glycol) fibers are reported. Refractive indices, intrinsic birefringence, mean polarizability per unit volume, optical orientation function, density, volume fraction of crystalline material, weight fraction crystallinity, and volume fraction of amorphous and work per chain of these fibers have been evaluated at different draw ratios. A comparison of optical and structure parameters for copolyester fiber and referenced monopolyester fiber has been done. This study has been carried out by means of computerized double-refracting Pluta interference microscope combined with opto-mechanical devices. Microinterferograms and relationships between the parameters obtained are given for illustration.

Interferometric Determination of Structural Properties of PEN Highly Oriented Fiber

Some optical and structural properties of Poly(ethylene naphthalate-2.6-dicarboxylate), PEN, highly oriented fiber was determined using an automatic variable wavelength interferometric, VAWI, technique. This technique is commonly used jointly with the double refracting polarizing interference microscope designed by Pluta. The microscope was used in two different positions, the subtractive position for determining the spectral dispersion curves of the birefringence and the crossed position for determining the spectral dispersion curves of the refractive indices. The resulting data are utilized to calculate some dispersion and structural parameters such as Cauchy's constants, natural wavelength, dispersion energy, oscillation energy, polarizability per unit volume, dielectric constant, dielectric susceptibility, optical orientation function, and the orientation angle. Microinterferograms are given for illustration.

Influence of Drawing and Temperature on the Optical and Structural Properties of Monofilament PP Sutures

Abstract The influence of drawing and temperature on the optical and structural properties of monofilament polypropylene sutures (PP) were investigated using interferometry. Two techniques have been used in this study: 1) the polarizing interference microscope, 2) multiple-beam Fizeau interferometry. The polarizing interference microscope is used to study the variation of refractive indices and birefringence of PP sutures at different draw ratios and stresses. The stress-strain diagram of PP sutures was studied. The resulting data was used to calculate the average work per chain, Poisson's ratio, strain optical coefficient, Young's modulus and optical orientation function. Multiple-beam Fizeau interferometry was used to study the temperature effect on optical properties of PP sutures with temperature ranging from 19 to 40°C. Relationships between the optical parameters at different temperatures are given. Calculation of the density, crystallinity, dielectric constant and dielectric susceptibility at different temperatures are done. The results obtained, clarify the effect of drawing and temperature on the structure of PP sutures. Microinterferograms are given for illustration.

Contribution of interferometry in evaluating structural parameters for drawn textile fibres

AbstractTwo‐beam and multiple‐beam interferometric techniques were used to determine the refractive indices, birefringence and isotropic refractive index of nylon 6 and polyethylene fibres drawn to different draw ratios. These optical parameters contributed in solving the density problem of the drawn fibres in terms of the density of the undrawn fibre. Related parameters such as, crystallinity, number of monomer units per unit volume, polarizability of monomer unit, molar refractivity and certain other parameters were then calculated. In addition, mechanical parameters, such as shrinkage stress, strain and stress optical coefficients, were also calculated. Moreover, the optical orientation function and orientation angle were evaluated. Microinterferograms and relationships between the parameters obtained are given for illustration. Copyright © 2004 Society of Chemical Industry

Determination of optical properties, dispersion, and structural parameters of poly(ethylene terephthalate) fibers using automatic variable wavelength interferometry technique

Automatic variable wavelength interferometry (VAWI) is used in combination with a Pluta double refracting polarizing interference microscope for measuring the spectral dispersion parameters of the refractive indices of poly(ethylene terephthalate) (PET) highly oriented yarn fibers (1000 denier/250 filaments). The resulting data are utilized to calculate the spectral dispersion and structural parameters such as Cauchy's constants, the dispersion energy, the oscillation energy, the density, the mean polarizability of the monomer unit, the number of monomer units per unit volume, the dielectric constant, the electric susceptibility, the optical orientation function, and the electric polarizability constant. Microinterferograms are given for illustration. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1737–1742, 2003

Induced birefringence in aqueous bio-macromolecular solutions

On the basis of results of linear and nonlinear optics investigation in L-Glutathione and Bovine-Serum Albumine aqueous solutions, the Kerr constants, nonlinear polarizabilities, effective optical anisotropies, anisotropic factor, scattering coefficient and orientation function as well as polarizability and optical anisotropy were calculated.

Opto-thermal behavior of polypropylene fibres using a modified hot-stage attached to the interference microscope

The influence of temperature on the optical and structural properties of three samples of polypropylene fibres (having different deniers) has been studied over the temperature range (28–67 oC). A hot-stage attached with the Pluta microscope has been modified for this purpose. The effect of temperature on the refractive indices ( n ∥, n ⊥), the mean polarizabilities per unit volume ( P ll, P ⊥) and the optical orientation function f(θ) have been investigated for each sample. The thermal coefficients of the refractive indices were determined. The refractive index profiles are also provided at different temperatures for each of the three tested samples. Microinterferograms are given for illustration.

Interferometric determination of (skin-core) optical andorientation structural parameters of drawn polypropylene fibres

Multiple-beam Fizeau fringes in transmission were used to study the changesof the principal optical properties of six samples of drawn polypropylenefibres. The resulting data of the mean, skin and core refractive indicesand birefringence of these fibres were used to calculate some structuralparameters such as the optical orientation function, orientation angle, theisotropic refractive index, the virtual refractive index, the number ofmolecules per unit volume and the random links per chain. Poisson's ratio and thestrain optical coefficient are also determined. The distribution ofsegments at an angle with respect to the draw ratio and the electricpolarizability constant (Δα/3α0) and other parametersand constants are determined. The generalized Lorentz-Lorenz equationgiven by de Vries has been used to compare the results obtained by Herman'soptical orientation function. Microinterferograms, tables and graphs aregiven for illustration.

Shrinkage and mechanical structural variations in cold drawn perlon fibers

In the present work nylon 6 (perlon) fibers were stretched at room temperature. The Pluta polarizing interference microscope with a micro-strain device was used for measuring some optical and mechanical parameters of the fibers. The values of the fully oriented refractive indices n 1 and n 2 were found to be 1.630 and 1.561. The generalized Lorentz–Lorenz equation given by de Vries was used to determine structural parameters of the fibers. Comparison between Herman's optical orientation function formula and the corrected formula by de Vries are given. The changes in the molecular orientation were evaluated to obtain the values of orientation functions f 2( θ), f 4( θ), f 6( θ), < P 2 (cos θ)> and < P 4 (cos θ)>. In addition, the shrinkage stress was found to increase with increase of the draw ratio. The dielectric constant, the dielectric susceptibility and the number of moles of network chains per unit volume were also calculated. Microinterferograms and curves are given for illustration.

Refractive index profile of polyethylene fiber using interactive multiple-beam fizeau fringe analysis

A multiple-beam interference Fizeau fringes technique is used to measure the refractive index profile of drawn polyethylene fiber. The interference fringe shift in the fiber region has been analyzed automatically using an interactive algorithm. The method takes into consideration the refraction of the light beam when crossing the fiber. Plane polarized light vibrating parallel and perpendicular to the fiber axis are used to obtain the refractive index profiles of both cases. These profiles are used to determine some optical parameters such as the birefringence, the optical orientation function, the polarizability per unit volume, and the value Δα/3αo, which related to the material structure. The reliability of the method is tested considering the results of drawn polyethylene fiber samples using the manual technique. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 3099–3106, 2000

Opto-thermal properties of fibers: 8. Optical and mechanical parameters variations on cold drawn thermally treated nylon 6-6 fibers

Refractive indices and birefringence changes with strain produced by different stresses in annealed and unannealed nylon 6-6 fibers (Promilan, Toray Industries Inc. Japan) were measured interferometrically. Calculations were carried out to determine the strain optical coefficient, the orientation factor, the orientation angle, the number of molecules per unit volume, the isotropic refractive index and the virtual refractive index. The effect of the draw ratio on the refractive index profile was studied. The generalized Lorentz–Lorenz equation given by de Vries has been used to compare the results obtained by Hermans' optical orientation function.

Opto-thermal properties of fibers. XV. A study of the drawing behavior of quenched poly(ethyleneterephthalates) fibers

Studies of the mechanical and optical properties of undrawn uniaxially stretched polyester PET (Egyptian manufacture) fibers by annealing and cold drawing were performed. The optical properties and strain produced in PET fibers at different conditions were measured interferometrically at room temperature. A two-beam interferometric technique was used to determine refractive indices and birefringence of the investigated PET samples with strain produced by different stresses. Using a microstrain device attached to a microscope stage and through the application of the appropriate mathematical equations, the refractive indices and the birefringence values were determined as a function of the draw ratios. The resulting data were utilized to calculate the polarizability per unit volume, the number of molecules per unit volume, Poisson's ratio, the strain optical coefficient, and several other parameters and constants. Also, some structural parameters are determined, such as form birefringence, the virtual refractive index, the harmonic mean polarizability of the dielectric, the harmonic mean specific refractivity, and the isotropic refractive index. The generalized Lorentz–Lorenz equation given by de Vries is used to determine PET fiber structure parameters. Comparison between the results have been compared with Hermans' optical orientation function. Relationships between the various optical parameters and the draw ratios are plotted, and the effect of draw ratio on the refractive index profile is studied. Microinterferograms are given for illustration. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1869–1880, 1999

Opto-thermal properties of fibers: 6. Evaluation of some optical structural parameters obtained due to annealing nylon 6 fiber

In the present work nylon 6 fibers were annealed at a constant temperature 160±1°C and different times. The Pluta polarizing interference microscope and an acoustic method were used previously for measuring some optical parameters, and the densities of these fibers. The results obtained were utilized for calculations of polarizabilities per unit volume, the isotropic refractive index by utilizing the Lorentz–Loranz equation, and the number of molecules per unit volume. The density results were used to calculate the degree of crystallinity and the mean density fluctuation at different annealing conditions. Also, some structural parameters such as the virtual refractive index, the harmonic mean polarizability of the dielectric, the harmonic mean specific refractivity and the number of the monomeric units per unit volume were obtained. Relationships between the structural parameters with different times are given for these fibers. The generalized Lorentz–Loranz equation given by de Vries is used to determine nylon 6 fiber structural parameters. Comparison between Hermans optical orientation function formula and the corrected formula by de Vries are given. Illustration is given using graphs and microinterferograms.

Optothermal properties of fibers?20?relation between physical structure and mechanical properties of cold drawn polypropylene fibers

The structure of annealed polypropylene (PP) fibers is studied interferometrically using two-beam Pluta polarizing interference microscope connected to a device to study the draw ratio with birefringence changes dynamically. Relations of drawing changes with some optical and physical parameters are given. Evaluation of average work per chain, work per unit volume, reduction in entropy caused by elongation, and the work stored in the body as strain energy were determined. Also the resulting optical data were utilized to evaluate the orientation factor, the orientation angle, the virtual refractive index, and the number of molecules per unit volume. The value of (Δα/3α0), which depends upon the molecular structure of the polymer, remains constant. Relations between the physical and optical parameters with different strains are given for these fibers. The generalized Lorentz–Lorenz equation given by de Vries is used to determine polypropylene fiber structural parameters. Comparison between Hermans optical orientation function formula and the corrected formula by de Vries are given. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 819–831, 1999

Opto-thermal properties of fibers. XVI. Macrostructural and optical properties of cold-drawn, quenched PET fibers

In this article, the relation between the macrostructural changes in uniaxially stretched polyester (PET) fibers, caused by heat treatment, and quenched in coarse-grain ice were studied. The developing macrostructure was determined using double-beam interferometry. Application was carried out by two-beam interferometry to determine the optical parameters. Using a two-beam Pluta polarizing interference microscope connected to a device to dynamically study the draw ratio with birefringence changes. The relations of drawing changes with some optical parameters are given. The evaluation of density, the mean square density fluctuation, crystallinity, amorphous orientation, crystalline orientation functions, the mean square density fluctuation 〈η2〉, the number of chains per unit volume Nc, and the number of random links between the network junction points N(1) have been found. The results obtained clarify the effect of annealing time and temperature with different draw ratios on the structure of PET fibers. Also, the optical results were used to calculate an optical orientation function and an optical orientation angle of drawn, quenched PET fibers. Relations between the optical data, draw ratios, and other parameters with different quenching conditions are given for these fibers. The change of the refractive index profile of the quenched PET fibers with various conditions are given. Illustrations are given using graphs and microinterferograms. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1881–1894, 1999