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

2019 ◽  
Vol 33 (12) ◽  
pp. 1950111 ◽  
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.

scholarly journals Ion Charge Influence on the Molecular Structure of Polyethylene Terephthalate Films after Irradiation with Swift Heavy Ions

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 479
Author(s):  
Adil Z. Tuleushev ◽  
Maxim V. Zdorovets ◽  
Artem L. Kozlovskiy ◽  
Fiona E. Harrison
Keyword(s):  
Polyethylene Terephthalate ◽  
Structural Changes ◽  
Diffraction Method ◽  
Dipole Interaction ◽  
Heavy Ion ◽  
Cross Linking ◽  
X Ray Diffraction ◽  
Chain Molecules ◽  
Repeat Units ◽  
Pet Film

We report here experimental results investigating the influence of the initial swift heavy ion charge on the structure of polyethylene terephthalate (PET) film after irradiation, using a structurally sensitive X-ray diffraction method. Kr ions with an energy of 100 MeV and charges of 13+, 14+, and 15+ were each used at irradiation fluences of 5 × 1010, 7.5 × 1010, 1 × 1011, 2.5 × 1011 and 5 × 1011 ions/cm2. At constant energy and irradiation fluence, the post-irradiation structural changes in PET film show a clear dependence on the initial ion charge. As either the fluence or ion charge increase, the latent tracks begin to overlap, leading to cross-linking of PET chain molecules to form rotational isomers (rotamers). We use the fluence corresponding to the onset of overlapping to estimate the size of latent tracks for different ion charges. At the highest fluences, the latent tracks become entirely overlapped, and the interchain cross-linking extends throughout the whole film. Since this cross-linking is due to the dipole–dipole interaction of subunits of repeat units of PET chain molecules, it is reversible, in contrast to the well-known chemical cross-linking of polymer chain molecules under irradiation.

Characterization of silica polymorphs in kaolins by X-ray diffraction before and after phosphoric acid digestion and thermal treatment

2005 ◽  
Vol 552 (1-2) ◽  
pp. 201-206 ◽  
Author(s):  
Sibel Kahraman ◽  
Müşerref Önal ◽  
Yüksel Sarıkaya ◽  
İhsan Bozdoğan
Keyword(s):  
Thermal Treatment ◽  
Phosphoric Acid ◽  
Acid Digestion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After

scholarly journals Characterization Of Microstructure And Selected Properties of SnSbCu Alloy After FSP

2021 ◽  
Author(s):  
Joanna Hrabia-Wiśnios ◽  
Beata Leszczyńska-Madej ◽  
Marcin Madej ◽  
Aleksandra Węglowska
Keyword(s):  
Flexural Strength ◽  
Diffraction Method ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
Linear Speed ◽  
X Ray ◽  
Friction Stir ◽  
Before And After ◽  
Bearing Alloy

Abstract The paper presents the results of research on the microstructure and selected mechanical properties of the SnSbCu bearing alloy after friction stir processing (FSP). The Whorl tool was used for modification; the process was carried out using two rotational speeds of the tool: 280 and 450 RPM and a constant linear speed of 355 mm/min. Microstructure studies were performed employing the techniques of light microscopy and scanning electron microscopy along with analysis of the chemical composition of micro-areas. Additionally, the phase composition was investigated by means of the X-ray diffraction method and statistical analysis of the precipitates present in the investigated alloy. In addition, hardness, flexural strength and uniaxial compression tests were performed before and after FSP modification. It was proved that using FSP to modify the SnSbCu alloy promotes refinement and homogenization of the microstructure, as well as improvement of the flexural strength, whereas no changes in the hardness level were found.

Effect of Thermal Treatment on the Physical Properties of Electrospun PVDF Membrane

2012 ◽  
Vol 591-593 ◽  
pp. 1113-1116
Author(s):  
Si Chen Cheng ◽  
Yin Zheng Liang ◽  
Yi Ping Qiu
Keyword(s):  
Thermal Treatment ◽  
Tensile Property ◽  
Tensile Testing ◽  
Vinylidene Fluoride ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
Pvdf Membrane ◽  
X Ray ◽  
Before And After ◽  
Poly Vinylidene Fluoride

The electrospinning technique was used to produce poly (vinylidene fluoride) (PVDF) membrane. Thermal treatment was introduced to improve the mechanical property and dimensional stability. In this paper, the PVDF membranes before and after thermal treatment were characterized by Scanning electron microscope (SEM), differential scanning calorimeter (DSC) and wide angle X-ray diffraction (WAXD), tensile testing. The crystallinity, tensile property, as well as melting temperature changed with the treated temperature. The results hows that thermal treatment could notably increase the tensile property of electrospun PVDF membrane and 160°C is a proper temperature for thermal treating

scholarly journals Effect of pH on hemicellulose extraction and physicochemical characteristics of solids during hydrothermal pretreatment of eucalyptus

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6627-6635
Author(s):  
Zeguang Yang ◽  
Liming Cao ◽  
Yan Li ◽  
Min Zhang ◽  
Fanyan Zeng ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Structural Changes ◽  
Crystallinity Index ◽  
Physicochemical Characteristics ◽  
Total Dissolved Solids ◽  
Hydrothermal Pretreatment ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Effects Of Ph

The effects of pH on residual solids (RS), total dissolved solids (TDS), carbohydrates, and lignin in eucalyptus during hydrothermal pretreatment were studied. The balance between RS and TDS was obtained at pH 4.0 in hydrothermal pretreatment with pre-adjustment pH. The yield of hemicellulose increased, and oligosaccharides dominated. Hemicellulose had the highest dissolution rate, and cellulose and lignin had the lowest dissolution rate at pH 4.0. The crystallinity index (CrI) and structural transformation of lignin was analyzed by X-ray diffraction (XRD) and nuclear magnetic resonance spectroscopy (NMR) with or without pretreatment. The CrI at pH 4.0 was 64.2% higher than that with the traditional hydrothermal pretreatment (62.1%). The β-O-4 bonds, OMe, and phenylcoumarane of lignin were protected. The highest hemicellulose extraction and minimal physicochemical structural changes were obtained at pH 4.0.

Corrosion Behavior of Some Steels in Ionic Liquids Based on Choline Chloride

2018 ◽  
Vol 69 (10) ◽  
pp. 2642-2647 ◽  
Author(s):  
Elena Ionela Neacsu ◽  
Virgil Constantin ◽  
Cristina Donath ◽  
Kazimir Yanushkevich ◽  
Aliona Zhivulka ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Corrosion Behaviour ◽  
Choline Chloride ◽  
Diffraction Method ◽  
Corrosion Process ◽  
Specific Magnetization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Special Steels

The corrosion behaviour of special steels (OL44, OL52, SS1.4571) exposed to choline chloride (ChCl) based ionic liquids, has been investigated by polarization curves method at 80�C. Micrographic images before and after corrosion were obtained. The corresponding corrosion parameters in ChCl-Oxalic acid and ChCl-Malonic acid were calculated. The crystal structure was studied before and after the corrosion process by using X-ray diffraction method. The specific magnetization was investigated by ponderomotive method.

scholarly journals Structural changes of Cr-beidellite treated up to 1350 °C in oxygen or nitrogen atmospheres

Cerâmica ◽  
2018 ◽  
Vol 64 (369) ◽  
pp. 64-68
Author(s):  
H. S. Santos ◽  
A. M. Cesio ◽  
M. Gauna ◽  
V. F. Justo ◽  
C. Volzone
Keyword(s):  
Thermal Analysis ◽  
High Temperature ◽  
Thermal Treatment ◽  
Structural Changes ◽  
Pillared Clay ◽  
Nitrogen Atmosphere ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineralogical Phases

Abstract Beidellite clay mineral after intercalation of OH-Cr(III) species were thermally analyzed up to 1350 °C in oxygen and nitrogen atmospheres. OH-Cr-beidellite can be used as a pillared clay precursor for catalysis or as adsorbent applications. However, in this paper beidellite enriched in chromium were analyzed at different thermal treatments up to high temperature for evaluating structural changes for possible future ceramic applications. The structural changes were followed by thermal analysis and X-ray diffraction. The thermal treatment of OH-Cr-beidellite in oxygen and nitrogen atmospheres developed different mineralogical phases up to 1050 °C, but at higher temperatures, the same phases were developed in both atmosphere treatments. Eskolaite phase (Cr2O3) appeared in the sample after heating at 400 °C in oxygen atmosphere, whereas grimaldite (CrO-OH) in nitrogen atmosphere, maintaining the starting phases. At 1000 °C the raw clay minerals disappeared, as it is knew. At 1050 °C in nitrogen atmosphere, grimaldite was absent and eskolaite appeared. At 1350 °C in the samples calcined in both atmospheres, quartz, cristobalite and mullite as the main phases and in lower contents aluminum oxide and aluminum-chromium oxide [(Al,Cr)2O3] were present.

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