Raman Structural Study Of Olefin Blends

We carried out detailed Raman structural study ofmelt-mixed blends of linear low-densitypolyethylene (PE) and isotactic polypropylene (PP).The relative content of PE in the PE/PP blendsvaried from 13 to 75 %. We show that Ramanspectroscopy can be effectively used for aquantitative analysis of phase and conformationalcompositions of these blends. The changes in thesecompositions due to changing the content of theblend components are discussed. Also, we studied astructure of the amorphous phase of reactor blendsof PE with random ethylene/1-hexene copolymer(CEH)

Raman structural study of random olefin copolymers

In this work we present Raman study of random copolymers of ethylene and propylene with a number of α-olefins, and investigation of the relationships between the spectral characteristics of the Raman lines and the copolymer structural properties. For both the copolymers we observed rapid decrease in the crystallinity and conformational order as the content of the incorporated monomer increases

ULTRAVIOLET RADIATION OF THE SURFACE DISCHARGE IS A PREIONIZER OF HIGH PRESSURE ATOMIC-MOLECULAR IMPURITIES

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Ti:Sapphire waveguide lasers

Titanium-doped sapphire is one of the most prominent laser materials and is appreciated for its excellent heat conductivity and broadband gain spectrum, allowing for a wide wavelength tunability and generation of ultrashort pulses. As one of the hardest materials, it can also serve as a model system for the fabrication of optical waveguide structures in dielectric crystalline materials and applications in integrated optics. In this paper, we review the recent approaches towards gain and laser operation in Ti:sapphire optical waveguides, including epitaxial growth, surface micro-structuring, and in-depth refractive-index modifications. Several methods including pulsed laser deposition, reactive ion etching, ion in-diffusion, light-ion implantation, and femtosecond-laser irradiation are presented and the results with respect to obtained refractive-index profiles, waveguide propagation losses, and laser performance are discussed

Problems of measurement of dense plasma heating in laser shock-wave compression

Experimental results of heating measurements of matter carried out in a study of laser-driven shock waves in aluminum (Batani et al. 1997) are discussed. The measured temporal evolution of the "color" temperature of the rear surface of the target is compared with that computed by a numerical code. It has been established that the target preheating can substantially affect optical signal features recorded from the rear side of the target, and consequently influence upon the accuracy of temperature and pressure measurements of the material behind the shock wave front

Raman spectroscopic evaluation of molecular orientation in polysulfone

In this paper, we present for the first time a Raman spectroscopic method for the determination of molecular orientation in uniaxially oriented polysulfone (PSU)

Raman spectroscopy evaluation of Polyvinylchloride structure

Polyvinylchloride (PVC) is one of the most widely used commercial polymers, and the field of its application continues to expand rapidly. Effective development of state-of-art functional materials, such as PVC-based nanocomposites, copolymers, blends and fabrics, subjected to special kinds of treatment, requires elaboration of new, more informative approaches of PVC structure evaluation. Industrial PVC is characterized by variety of states of macromolecules and very low degree of crystallinity. Thus, the best way to evaluate PVC structure is to apply vibrational spectroscopy, the unique feature of which is high information capacity in the study of the different configurational and conformational states of macromolecules. Most of the Raman spectroscopic methods of PVC structure testing were developed more than 20 years ago. Therefore, improvement of the already recognized methods and development of modern computerbased processing of the spectra for the detailed quantitative analysis of PVC structure are important. In this work, we present an extensive study of polarized Raman spectra of a number of industrial grades of PVC powder and films, prepared from solutions of tetrahydrofuran and acetophenone. For PVC itself and residues of the solvents, remained in the films, we determined the number of Raman lines and their spectral characteristics. These data were used to assign accurately PVC Raman lines and to evaluate structure of different grades of PVC powder and films