scholarly journals Spectral Properties of PMMA Films Doped by Perylene Dyestuffs for Photoselective Greenhouse Cladding Applications

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 494 ◽  
Author(s):  
S. El-Bashir ◽  
M. AlSalhi ◽  
F. Al-Faifi ◽  
W. Alenazi

Luminescent polymethylmethacrylate (PMMA) films were prepared by the solvent-casting technique from polymer solution doped with different concentrations of red perylene dyestuffs (KREMER 94720 and KREMER 94739). The effect of the dye concentration on the structure and spectroscopic properties was studied using X-ray diffraction (XRD), transmission electron microscope (TEM) optical absorption, and fluorescence spectroscopy. The optimum dye concentration of photoselective PMMA films was determined by the fluorescence spectroscopy measurements and showed the best emission properties for the doping concentration 10−3 wt % of the investigated dyes. The accelerated photostability tests showed promising stability of the prepared films towards terrestrial solar ultraviolet radiation (UVA). The results endorsed a promising application of the investigated films in photoselective greenhouse cladding applications as the optimized film fluoresces at the action spectra of special chlorophyll a.

2014 ◽  
Vol 793 ◽  
pp. 143-149
Author(s):  
J.R. Romero-Romero ◽  
J. Luis López-Miranda ◽  
R. Esparza ◽  
M.A. Espinosa-Medina ◽  
G. Rosas

FeAl3 and FeAl2 intermetallic alloys composition was produced by conventional casting technique. Typically these intermetallic alloys are susceptible to hydrogen environment embrittlement. In this process, water vapor in the air induced cleavage fracture of intermetallic alloys. In order to take advantage of this phenomenon, we evaluate the embrittlement reaction during ball-milling of the pre-alloyed intermetallic material and water under different milling times. During the corrosion reaction, the amount of hydrogen releases was correlated to the amount of aluminum hydroxide formation. The obtained results were based on X-ray diffraction and scanning and transmission electron microscopy. It was observed that as the milling time increased the amount of hydrogen liberated is increased. The intermetallic FeAl3 the 72.95 wt. % reacted with water and the hydrogen release was 0.7769 L and is near the theoretical values that can be obtained.


2017 ◽  
Vol 41 (19) ◽  
pp. 10880-10889 ◽  
Author(s):  
Ping Yuan ◽  
Ming Zhang ◽  
Ninglin Zhou ◽  
Cheng Chi ◽  
Xiaohong Chu ◽  
...  

In this study, a carbon dots-genipin covalent conjugate (CDs–GP) was synthesized, characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and fluorescence spectroscopy (FL).


2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
R. M. Ahmed ◽  
S. M. El-Bashir

FullereneC60has stimulated intense interest for scientific, industrial, and medical community because of its unique structure and properties. In the present study we prepared fullerene-doped nanocomposite films based on PMMA, PVAc, and PMMA/PVAc blend. Observations made by transmission electron microscope (TEM) showed the uniform dispersion ofC60nanoparticles in the polymer matrices. Also, X-ray diffraction measurements indicated thatC60has a tendency to form crystallites in the polymer matrices. In addition, the concentration effect of fullereneC60was investigated using optical absorption and photoluminescence spectroscopy. The spectroscopic properties of such films recommended their application in photonics and solar energy conversion.


Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 274
Author(s):  
Azlin Fazlina Osman ◽  
Lilian Siah ◽  
Awad A. Alrashdi ◽  
Anwar Ul-Hamid ◽  
Ismail Ibrahim

In this work, dolomite filler was introduced into thermoplastic starch (TPS) matrix to form TPS-dolomite (TPS-DOL) biocomposites. TPS-DOL biocomposites were prepared at different dolomite loadings (1 wt%, 2 wt%, 3 wt%, 4 wt% and 5 wt%) and by using two different forms of dolomite (pristine (DOL(P) and sonicated dolomite (DOL(U)) via the solvent casting technique. The effects of dolomite loading and sonication process on the mechanical properties of the TPS-DOL biocomposites were analyzed using tensile and tear tests. The chemistry aspect of the TPS-DOL biocomposites was analyzed using Fourier transform infrared spectroscopy (FTIR) and X-Ray Diffraction (XRD) analysis. According to the mechanical data, biocomposites with a high loading of dolomite (4 and 5 wt%) possess greater tensile and tear properties as compared to the biocomposites with a low loading of dolomite (1 and 2 wt%). Furthermore, it is also proved that the TPS-DOL(U) biocomposites have better mechanical properties when compared to the TPS-DOL(P) biocomposites. Reduction in the dolomite particle size upon the sonication process assisted in its dispersion and distribution throughout the TPS matrix. Thus, this led to the improvement of the tensile and tear properties of the biocomposite. Based on the findings, it is proven that the sonication process is a simple yet beneficial technique in the production of the TPS-dolomite biocomposites with improved tensile and tear properties for use as packaging film.


Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 378 ◽  
Author(s):  
Junjing Li ◽  
Huan Wang ◽  
Liang Wang ◽  
Chang Ma ◽  
Cong Luan ◽  
...  

Noble metal palladium modified foamed nickel electrode (Pd/foam-Ni) was prepared by electrodeposition method. The fabricated electrode showed better catalytic performance than the Pd/foam-Ni prepared by conventional electroless deposition. The catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Electrocatalytic activity of the Pd/Ni was studied for the hydrodechlorination of monochlorophenol isomers. The Pd/Ni exhibited good catalytic activity for 3-chlorophenol (3-CP). Complete decomposition of chlorophenol isomers could be achieved within 2 h, and the hydrodechlorination process conformed to the pseudo-first-order kinetic model. It showed a supreme stability after recycling for 5 times. The Pd/Ni exhibited a promising application prospect with high effectiveness and low Pd loading.


2012 ◽  
Vol 622-623 ◽  
pp. 263-270 ◽  
Author(s):  
Ali Salehabadi ◽  
Mohamad Abu Bakar

Nano-biohybrid, based on biodegradable polyester, poly (3-hydroxybutyrate) (PHB), and a commercial organo modified montmorillonite (MMT), were prepared by solvent casting technique. Morphology and non-isothermal degradation of PHB and PHB/MMT hybrids were characterized by POM and TG-DTG technique. In the composite materials, an increase MMT loading in the PHB decreased the onset temperature (Tonset) of thermal degradation, while it achieved higher values upon increasing the heating rate. Kissinger plots deduced a trend of the degradation activation energy, Ed, which was related to the agglomeration of MMT. The thermal degradation rate constant, k, was related to the MMT loading in PHB. X-ray diffraction analysis confirmed the expansion of MMT silicate layers.


RSC Advances ◽  
2014 ◽  
Vol 4 (59) ◽  
pp. 31155-31161 ◽  
Author(s):  
Young In Choi ◽  
Youngku Sohn

Eu(iii) and Tb(iv) activators were embedded in quantum size SnO2 nanoparticles by a hydrothermal method and their morphologies, crystal structures and spectroscopic properties were examined by transmission electron microscopy, X-ray diffraction crystallography, UV-visible absorption, and 2D/3D-photoluminescence mapping.


Author(s):  
R. E. Herfert

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.


Author(s):  
R. Gronsky

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.


Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.


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