Silica structural changes induced by thermal treatment or ionic implantation as probed by IR reflectance spectroscopy

AbstractThe mineral conichalcite from the western part of Bagdad mine, Bagdad, Eureka District, Yavapai County, Arizona, USA has been characterized by electronic, near-infrared (NIR), Raman and infrared (IR) spectroscopy. Scanning electron microscopy (SEM) images show that the mineral consists of bundles of fibres. Calculations based on the results of the energy dispersive X-ray analyses on a stoichiometric basis show the substitution of arsenate by 12 wt.% of phosphate in the mineral. Raman and IR bands are assigned in terms of the fundamental modes of AsO43− and PO43− molecules and are related to the mineral structure. Near-IR reflectance spectroscopy shows the presence of adsorbed water and hydroxyl units in the mineral. The Cu(II) coordination polyhedron in conichalcite can have at best pseudo-tetragonal geometry. The crystal field and tetragonal field parameters of the Cu(II) complex were calculated and found to agree well with the values reported for known tetragonal distortion octahedral complexes.

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XRD investigation of thermal degradation of some gamma-irradiated polyethylene terephthalate samples

International Journal of Modern Physics B ◽

10.1142/s021797921950111x ◽

2019 ◽

Vol 33 (12) ◽

pp. 1950111 ◽

Cited By ~ 1

Author(s):

Mihai Todica ◽

Zoltan Kovacs-Krauss ◽

Carmen Niculaescu ◽

Marieta Mureşan-Pop

Keyword(s):

Thermal Treatment ◽

Polyethylene Terephthalate ◽

Structural Changes ◽

Diffraction Method ◽

Resonance Spectroscopy ◽

X Ray Diffraction ◽

X Ray ◽

Before And After ◽

Gamma Irradiated ◽

Different Doses

The modification of local structure of some commercial polyethylene terephthalate (PET) samples, gamma irradiated at different doses, was investigated by X-ray diffraction method before and after thermal treatment. Before the thermal treatment, the samples exposed to different doses of gamma radiations, does not show noticeable structural changes. However, the gamma exposure affects the thermal behavior of samples submitted to melting–cooling process. These modifications have been highlighted by X-ray diffraction, and confirmed also by thermal analysis and electron spin resonance spectroscopy.

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Lignin Content in Paper Fibers Assessed Using IR Reflectance Spectroscopy

Journal of Applied Spectroscopy ◽

10.1007/s10812-018-0588-6 ◽

2018 ◽

Vol 84 (6) ◽

pp. 1066-1071 ◽

Cited By ~ 2

Author(s):

O. Yu. Derkacheva ◽

D. O. Tsypkin

Keyword(s):

Lignin Content ◽

Reflectance Spectroscopy ◽

Ir Reflectance ◽

Paper Fibers

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Structural changes of polyvinylchloride fibre produced by thermal treatment

Polymer Science U S S R ◽

10.1016/0032-3950(69)90213-5 ◽

1969 ◽

Vol 11 (7) ◽

pp. 1726-1733 ◽

Cited By ~ 3

Author(s):

Z.P. Vysotskaya ◽

V.D. Fikhman ◽

V.M. Alekseyeva ◽

Yu.V. Glazkovskii ◽

Yu.A. Zubov ◽

...

Keyword(s):

Thermal Treatment ◽

Structural Changes

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Cross-linked Chitosan and Poly(allyl amine) Thin Films

MRS Proceedings ◽

10.1557/proc-750-y9.5 ◽

2002 ◽

Vol 750 ◽

Cited By ~ 1

Author(s):

Caroline L. Schauer ◽

Paul E. Schoen ◽

Frances S. Ligler

Keyword(s):

Thin Films ◽

Layered Materials ◽

Reflectance Spectroscopy ◽

Medical Diagnostics ◽

Index Of Refraction ◽

Soluble Form ◽

Software Modeling ◽

Light Refraction ◽

Ir Reflectance ◽

Allyl Amine

ABSTRACTThe alternation of chitin layers with various compounds allows nature to create novel materials with selective refractive properties. Various organisms employ layered materials for survival; for example, in butterflies such materials cause the apparent disappearance and reappearance during flight to evade predators. The selective light refraction is achieved through control of the thickness and index of refraction of the multiple layers. With the ultimate goal of reproducing these layers, thin single films of chitosan, the soluble form of chitin, and poly(allyl amine) have been prepared and their optical properties analyzed. Ellipsometry, reflectance IR, reflectance spectroscopy, SEM and software modeling were used to characterize these films. Possible applications for optical layered materials range from medical diagnostics to environmental monitoring.

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