Orientation of macromolecules at the interface of polymer and fillers

1999

J. Appl. Polym. Sci.

ABSTRACT: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 ͗ 2 ͘, the number of chains per unit volume N c , 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.

Section: Determination Of the Number Of Molecules Per Unit Volumementioning

confidence: 99%

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

1999

J. Appl. Polym. Sci.

“…The total number ( N ) of molecules per unit volume is determined from the birefringence Δ n and the difference in the polarizabilities of the macromolecules ( P ‖ − P ⟂ ) as follows:38 where P ‖ and P ⟂ are the polarizabilities per unit volume, which can be calculated using the equation used in our previous publication 39…”

Section: Theoreticalmentioning

confidence: 99%

Changes in orientation caused by UV irradiation of nylon 6 fibers

Shabana

J of Applied Polymer Sci

2003

ABSTRACT:The effect of UV radiation on the structural parameters that relate to the optical properties of nylon 6 fibers are investigated using interferometry. When the optical parameters are known, we can use them to calculate various orientation functions given by Hermans and de Vries. The properties of concern are the surface reflectivity, transparency, stress optical coefficient, stress due to UV irradiation, optical configuration parameter, segment anisotropy, dielectric constant, and susceptibility. The number of molecules per unit volume, isotropic refractive index, polarizability of a monomer unit, specific refractivity of the dielectric (along and across the fiber axis) and the form birefringence were obtained. The results are established by relationships designed to relate the calculated structural parameters to the time of exposure. The study demonstrates how the structural parameters change during exposure to UV radiation. Illustrations are given using graphs and microinterferograms.

“…By using multiple beam Fizeau fringes, we can obtain all the previous structural parameters mentioned, applying analogous equations (3)(4)(5)(6)(7)(8)(9)(10)(11)(12) for the skin and core.…”

Section: Apex Of Interferometer R C R Fmentioning

confidence: 99%

“…When a polymeric fibre is annealed, its structural behaviour is changed due to the combined effects of several structural processes, which depend on annealing temperature and time [6][7][8][9] . The present work deals with the applications of multiple-beam Fizeau fringes and acoustic techniques for investigating some of the optical and acoustic parameters of annealed PET fibres.…”

mentioning

confidence: 99%

Interferometric Determination of Orientation and Some Optical Parameters of annealed Polyester Fibres

Polymers and Polymer Composites

2001

Multiple-beam Fizeau fringes in transmission have been applied to annealed PET fibres, to determine the refractive indices of their skin and core layers for plane polarized monochromatic light at λ =546.1 nm, vibrating parallel and perpendicular to the fibre axis. We obtained the optical orientation parameters by applying the equations used by Hermans and Ward. Some structural parameters such as electric polarizability were determined. The density of the samples studied was measured by a system based on the theory of vibrating strings. The density and optical results were used to calculate the degree of crystallinity, the mean square density fluctuation, the form birefringence, the number of monomeric units per unit volume, the harmonic mean polarizability of the dielectric, and the harmonic mean specific refractive index. The generalized Lorentz-Lorenz equation given by de Vries was used to determine the structural parameters of annealed PET fibres. Comparisons between the experimental results and those obtained by using the Lorentz-Lorenz and Hermans equations are given. Refractive index profiles are also given. The results show the new reorientation and layer changes accompanying annealing under different conditions. Illustrations are given of multiple-beam microinterferograms in transmission.