Activation energy of copper-induced thermal degradation of chitosan acetate functional groups

2015 ◽  
Vol 35 (3) ◽  
pp. 231-239 ◽  
Author(s):  
Maria Mucha ◽  
Sylwia Ksiazek ◽  
Halina Kaczmarek
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Thermal Degradation ◽  
Functional Groups ◽  
Chemical Structure ◽  
Acetic Acid Solution ◽  
Cuo Nanoparticles ◽  
Casting Method ◽  
Modified Chitosan ◽  
Vis Spectroscopy

Abstract Thin films of chitosan acetate (CSA)-copper (II) [Cu (II)] complex were prepared by mixing Cu (II) oxide (CuO) nanoparticles in acetic acid solution of chitosan and the casting method. The changes in chemical structure of modified chitosan were confirmed by UV-Vis spectroscopy. Fourier transform infrared (FTIR) spectroscopy was applied to monitor thermal degradation processes occurring in chitosan and its composites with Cu. The changes in concentration of chitosan functional groups were observed. On a base of the kinetic constants of group thermal degradation at various temperatures, the activation energies for various groups were calculated. It was found that the presence of Cu (II) ions accelerates the thermal degradation of chitosan acetate. The higher the Cu (II) content was in the CSA matrix, the lower was the activation energy.

The Use of FT-IR for the Determination of Liquid Products Properties after the Tyres Thermal Degradation

2012 ◽  
Vol 260-261 ◽  
pp. 593-597
Author(s):  
Veronika Sassmanová ◽  
Zuzana Poláčková ◽  
Jaroslav Frantík ◽  
Stanislav Honus ◽  
Dagmar Juchelková
Keyword(s):  
Thermal Degradation ◽  
Ir Spectra ◽  
Functional Groups ◽  
Chemical Structure ◽  
Chemical Properties ◽  
Elementary Analysis ◽  
Liquid Products ◽  
Ft Ir ◽  
Pyrolysis Liquid

The article deals with the identification of a chemical structure of pyrolysis liquid occurring by the thermal degradation of tyre debris within the temperature interval from 500°C to 650°C and the temperature increase steps of 50°C in individual experiments and with the use of analytical methods GC/MS, FT-IR and the elementary analysis. The measured FT-IR spectra indicate the representation of functional groups included in measured samples. They could be used for the determination of basic chemical properties. There were changes in the chemical composition monitored as well as the creation of functional groups in the pyrolysis liquid on the basis of FT-IR spectra and GS/MS outcomes.

scholarly journals Synthesis and Characterization of CuPc-PEPC Composite Thin Films and Photovoltaic Devices by Drop Casting Method

2021 ◽  
Vol 57 (4) ◽  
pp. 134-144
Author(s):  
Tamara Potlog ◽  
Vadim Furtuna ◽  
Ion Lungu ◽  
Stefan Robu ◽  
Galina Dragalina ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Copper Phthalocyanine ◽  
Optical Transmittance ◽  
Xrd Analysis ◽  
Casting Method ◽  
Absorption Bands ◽  
Sem Images ◽  
Composite Thin Films ◽  
Vis Spectroscopy

Using a drop casting method, stronger absorbent and photosensitive composite thin films based on a copper-phthalocyanine (CuPc) oligomer and a poly (N-epoxypropylcarbazole) (PEPC) copolymer were developed. Morphology, structural behavior and optical properties of CuPc:PEPC composite thin films have been studied using scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-VIS spectroscopy. The SEM images of pure CuPc organic thin films show the formation of some elongated shapes, while the morphology of CuPc:PEPC composite thin films is mainly controlled by the content of CuPc. XRD analysis of the CuPc:PEPC composite thin films reveal good crystallinity and the beta-copper phthalocyanine phase. Study of optical properties of CuPc:PEPC composite thin films after annealing in hydrogen atmosphere show decrease of the average optical transmittance. In addition, the broadening of the absorption bands increases the light harvesting capacity of the composite material for photovoltaic applications.

Thermal Degradation Analysis of Fluorocarbon Thin Films prepared by an r.f. Sputtering with Poly (tetrafluoroethylene) Target

2013 ◽  
Vol 56 (4) ◽  
pp. 133-135
Author(s):  
Yuki IKEDA ◽  
Satoru IWAMORI ◽  
Hiroyuki MATSUMOTO ◽  
Kiyoshi YOSHINO ◽  
Itsuo NISHIYAMA ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Degradation ◽  
Degradation Analysis

scholarly journals Combustion and gasification characteristics of low-temperature pyrolytic semi-coke prepared through atmosphere rich in CH4 and H2

2021 ◽  
Vol 10 (1) ◽  
pp. 189-200
Author(s):  
Yuan She ◽  
Chong Zou ◽  
Shiwei Liu ◽  
Keng Wu ◽  
Hao Wu ◽  
...  
Keyword(s):  
Functional Groups ◽  
Chemical Structure ◽  
Nitrogen Adsorption ◽  
Inhibitory Effect ◽  
X Ray ◽  
Coke Reactivity ◽  
Reducing Gas ◽  
Reactivity Indexes ◽  
Infrared Spectrometer ◽  
Reducing Gases

Abstract Thermoanalysis was used in this research to produce a comparative study on the combustion and gasification characteristics of semi-coke prepared under pyrolytic atmospheres rich in CH4 and H2 at different proportions. Distinctions of different semi-coke in terms of carbon chemical structure, functional groups, and micropore structure were examined. The results indicated that adding some reducing gases during pyrolysis could inhibit semi-coke reactivity, the inhibitory effect of the composite gas of H2 and CH4 was the most observable, and the effect of H2 was higher than that of CH4; moreover, increasing the proportion of reducing gas increased its inhibitory effect. X-ray diffractometer and Fourier-transform infrared spectrometer results indicated that adding reducing gases in the atmosphere elevated the disordering degree of carbon microcrystalline structures, boosted the removal of hydroxyl- and oxygen-containing functional groups, decreased the unsaturated side chains, and improved condensation degree of macromolecular networks. The nitrogen adsorption experiment revealed that the types of pore structure of semi-coke are mainly micropore and mesopore, and the influence of pyrolytic atmosphere on micropores was not of strong regularity but could inhibit mesopore development. Aromatic lamellar stack height of semi-coke, specific surface area of mesopore, and pore volume had a favorable linear correlation with semi-coke reactivity indexes.

scholarly journals Design of Promising Heptacoordinated Organotin (IV) Complexes-PEDOT: PSS-Based Composite for New-Generation Optoelectronic Devices Applications

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1023
Author(s):  
María Elena Sánchez-Vergara ◽  
Leon Hamui ◽  
Elizabeth Gómez ◽  
Guillermo M. Chans ◽  
José Miguel Galván-Hidalgo
Keyword(s):  
Thin Films ◽  
Electronic Properties ◽  
Optoelectronic Devices ◽  
Density Variation ◽  
Structural Modifications ◽  
Mixed Ligands ◽  
Vis Spectroscopy ◽  
Group A ◽  
Poly Styrene Sulfonate ◽  
New Generation

The synthesis of four mononuclear heptacoordinated organotin (IV) complexes of mixed ligands derived from tridentated Schiff bases and pyrazinecarboxylic acid is reported. This organotin (IV) complexes were prepared by using a multicomponent reaction, the reaction proceeds in moderate to good yields (64% to 82%). The complexes were characterized by UV-vis spectroscopy, IR spectroscopy, mass spectrometry, 1H, 13C, and 119Sn nuclear magnetic resonance (NMR) and elemental analysis. The spectroscopic analysis revealed that the tin atom is seven-coordinate in solution and that the carboxyl group acts as monodentate ligand. To determine the effect of the substituent on the optoelectronic properties of the organotin (IV) complexes, thin films were deposited, and the optical bandgap was obtained. A bandgap between 1.88 and 1.98 eV for the pellets and between 1.23 and 1.40 eV for the thin films was obtained. Later, different types of optoelectronic devices with architecture “contacts up/base down” were manufactured and analyzed to compare their electrical behavior. The design was intended to generate a composite based on the synthetized heptacoordinated organotin (IV) complexes embedded on the poly(3,4-ethylenedyoxithiophene)-poly(styrene sulfonate) (PEDOT:PSS). A Schottky curve at low voltages (<1.5 mV) and a current density variation of as much as ~3 × 10−5 A/cm2 at ~1.1 mV was observed. A generated photocurrent was of approximately 10−7 A and a photoconductivity between 4 × 10−9 and 7 × 10−9 S/cm for all the manufactured structures. The structural modifications on organotin (IV) complexes were focused on the electronic nature of the substituents and their ability to contribute to the electronic delocalization via the π system. The presence of the methyl group, a modest electron donor, or the non-substitution on the aromatic ring, has a reduced effect on the electronic properties of the molecule. However, a strong effect in the electronic properties of the material can be inferred from the presence of electron-withdrawing substituents like chlorine, able to reduce the gap energies.

scholarly journals Multiscale analysis of the thermal degradation of polyamide 6,6: Correlating chemical structure to mechanical properties

2021 ◽  
Vol 185 ◽  
pp. 109496
Author(s):  
M. Pliquet ◽  
M. Rapeaux ◽  
F. Delange ◽  
P.O. Bussiere ◽  
S. Therias ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Degradation ◽  
Multiscale Analysis ◽  
Chemical Structure

scholarly journals ᶫ-Leucine Loading and Release in MIL-100 Nanoparticles

2020 ◽  
Vol 21 (24) ◽  
pp. 9758
Author(s):  
Ivan E. Gorban ◽  
Mikhail A. Soldatov ◽  
Vera V. Butova ◽  
Pavel V. Medvedev ◽  
Olga A. Burachevskaya ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Hydrothermal Synthesis ◽  
Cell Model ◽  
Metal Organic Framework ◽  
Acetic Acid Solution ◽  
Sorption Isotherms ◽  
Microwave Assisted Synthesis ◽  
High Porosity ◽  
Cytotoxicity Studies ◽  
Vis Spectroscopy

Synthesis of the MIL-100 metal-organic framework particles was carried out by hydrothermal (HT) and microwave (MW)-assisted methods. Transmission electron microscopy showed formation of microparticles in the course of hydrothermal synthesis and nanoparticles for microwave-assisted synthesis. Powder X-ray diffraction confirmed formation of larger crystallites for hydrothermal synthesis. Particle aggregation in aqueous solution was observed by dynamic light scattering. However, the stability of both samples could be improved in acetic acid solution. Nitrogen sorption isotherms showed high porosity of the particles. ᶫ-leucine molecule was used as a model molecule for loading in the porous micro- and nanoparticles. Loading was estimated by FTIR spectroscopy and thermogravimetric analysis. UV-VIS spectroscopy quantified ᶫ-leucine release from the particles in aqueous solution. Cytotoxicity studies using the HeLa cell model showed that the original particles were somewhat toxic, but ᶫ-leucine loading ameliorated the toxic effects, likely due to signaling properties of the amino acid.

scholarly journals Functionalized Reduced Graphene Oxide Thin Films for Ultrahigh CO2 Gas Sensing Performance at Room Temperature

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 623
Author(s):  
Monika Gupta ◽  
Huzein Fahmi Hawari ◽  
Pradeep Kumar ◽  
Zainal Arif Burhanudin ◽  
Nelson Tansu
Keyword(s):  
Thin Films ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Gas Sensor ◽  
Functional Groups ◽  
Recovery Time ◽  
Room Temperature ◽  
Co2 Gas ◽  
Reduced Graphene ◽  
Response And Recovery

The demand for carbon dioxide (CO2) gas detection is increasing nowadays. However, its fast detection at room temperature (RT) is a major challenge. Graphene is found to be the most promising sensing material for RT detection, owing to its high surface area and electrical conductivity. In this work, we report a highly edge functionalized chemically synthesized reduced graphene oxide (rGO) thin films to achieve fast sensing response for CO2 gas at room temperature. The high amount of edge functional groups is prominent for the sorption of CO2 molecules. Initially, rGO is synthesized by reduction of GO using ascorbic acid (AA) as a reducing agent. Three different concentrations of rGO are prepared using three AA concentrations (25, 50, and 100 mg) to optimize the material properties such as functional groups and conductivity. Thin films of three different AA reduced rGO suspensions (AArGO25, AArGO50, AArGO100) are developed and later analyzed using standard FTIR, XRD, Raman, XPS, TEM, SEM, and four-point probe measurement techniques. We find that the highest edge functionality is achieved by the AArGO25 sample with a conductivity of ~1389 S/cm. The functionalized AArGO25 gas sensor shows recordable high sensing properties (response and recovery time) with good repeatability for CO2 at room temperature at 500 ppm and 50 ppm. Short response and recovery time of ~26 s and ~10 s, respectively, are achieved for 500 ppm CO2 gas with the sensitivity of ~50 Hz/µg. We believe that a highly functionalized AArGO CO2 gas sensor could be applicable for enhanced oil recovery, industrial and domestic safety applications.

scholarly journals Vacuum-Free and Highly Dense Nanoparticle Based Low-Band-Gap CuInSe2 Thin-Films Manufactured by Face-to-Face Annealing with Application of Uniaxial Mechanical Pressure

Coatings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 484
Author(s):  
Matthias Schuster ◽  
Dominik Stapf ◽  
Tobias Osterrieder ◽  
Vincent Barthel ◽  
Peter J. Wellmann
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Coarse Grained ◽  
High Porosity ◽  
Low Band Gap ◽  
Seeding Layer ◽  
X Ray ◽  
Face To Face ◽  
Copper Indium ◽  
Vis Spectroscopy

Copper indium gallium sulfo-selenide (CIGS) based solar cells show the highest conversion efficiencies among all thin-film photovoltaic competition. However, the absorber material manufacturing is in most cases dependent on vacuum-technology like sputtering and evaporation, and the use of toxic and environmentally harmful substances like H2Se. In this work, the goal to fabricate dense, coarse grained CuInSe2 (CISe) thin-films with vacuum-free processing based on nanoparticle (NP) precursors was achieved. Bimetallic copper-indium, elemental selenium and binary selenide (Cu2−xSe and In2Se3) NPs were synthesized by wet-chemical methods and dispersed in nontoxic solvents. Layer-stacks from these inks were printed on molybdenum coated float-glass-substrates via doctor-blading. During the temperature treatment, a face-to-face technique and mechanically applied pressure were used to transform the precursor-stacks into dense CuInSe2 films. By combining liquid phase sintering and pressure sintering, and using a seeding layer later on, issues like high porosity, oxidation, or selenium- and indium-depletion were overcome. There was no need for external Se atmosphere or H2Se gas, as all of the Se was directly in the precursor and could not leave the face-to-face sandwich. All thin-films were characterized with scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and UV/vis spectroscopy. Dense CISe layers with a thickness of about 2–3 µm and low band gap energies of 0.93–0.97 eV were formed in this work, which show potential to be used as a solar cell absorber.

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