scholarly journals Investigation of Thermophysical Properties of Nanomagnetite-based Polymer Materials

2021 ◽  
Vol 15 ◽  
pp. 1527-1533
Author(s):  
Ekaterina L. Kuznetsova ◽  
Minggong Sha
Keyword(s):  
Synthetic Methods ◽  
Polymer Materials ◽  
Magnetic Characteristics ◽  
Particle Nucleation ◽  
Biological Responses ◽  
Insufficient Amount ◽  
Diffraction Patterns ◽  
Work Samples ◽  
Kinetics Of ◽  
Magnetite Phase

In this work, samples of magnetite nanoparticles are synthesized using various synthetic methods. It is shown that of the existing methods of magnetite synthesis, the most widespread is the method of coprecipitation of Fe2+ and Fe3+ salts. Less common, but of interest due to the slower and more controlled kinetics of particle nucleation, is the Fe2+ oxidation method. However, magnetite is unstable and under external influences its phase transition to maghemite can occur, which leads to a change in magnetic characteristics and a change in biological responses. After analyzing the results of the study of samples by the XRD method, the following conclusions can be drawn: The magnetite phase was identified by the characteristic peaks in the diffraction patterns for all samples, except for the sample with EDTA, which may be a consequence of an insufficient amount of the introduced oxidant, or poor diffusion of the oxidant to iron ions due to the formed chelate complex. It can be concluded that magnetite is a promising material for its use in industry and medicine.

Electron-diffraction studies in synthetic polymer materials

1983 ◽  
Vol 41 ◽  
pp. 362-365
Author(s):  
D.T. Grubb
Keyword(s):  
Electron Diffraction ◽  
Synthetic Polymer ◽  
Polymer Materials ◽  
Crystallographic Structure ◽  
High Dose ◽  
Electron Dose ◽  
Dose Rates ◽  
First Case ◽  
Diffraction Patterns ◽  
The Many

Diffraction studies in polymeric and other beam sensitive materials may bring to mind the many experiments where diffracted intensity has been used as a measure of the electron dose required to destroy fine structure in the TEM. But this paper is concerned with a range of cases where the diffraction pattern itself contains the important information.In the first case, electron diffraction from paraffins, degraded polyethylene and polyethylene single crystals, all the samples are highly ordered, and their crystallographic structure is well known. The diffraction patterns fade on irradiation and may also change considerably in a-spacing, increasing the unit cell volume on irradiation. The effect is large and continuous far C94H190 paraffin and for PE, while for shorter chains to C 28H58 the change is less, levelling off at high dose, Fig.l. It is also found that the change in a-spacing increases at higher dose rates and at higher irradiation temperatures.

Electron spectroscopic imaging (ESI) on multiphase polymer materials

1989 ◽  
Vol 47 ◽  
pp. 348-349
Author(s):  
H.-J. Cantow ◽  
M. Kunz ◽  
M. Möller
Keyword(s):  
Energy Loss ◽  
Melt Spinning ◽  
Chromatic Aberration ◽  
Element Distribution ◽  
Polymer Materials ◽  
Specific Energy Loss ◽  
Transmission Electron ◽  
Multicomponent Polymer ◽  
Diffraction Patterns ◽  
Image Planes

In transmission electron microscopy the natural contrast of polymers is very low. Thus the contrast has to be enhanced by staining with heavy metals. The resolution is limited by the size of the staining particles and by the fact that electrons with different energy are focused in different image planes due to the chromatic aberration of the magnetic lenses. The integration of an electron energy loss spectrometer into the optical coloumn of a transmission electron microscope offers the possibility to use monoenergetic electrons and to select electrons with a certain energy for imaging. Thus contrast and resolution are enhanced. By imaging only electrons with an element specific energy loss the element distribution in the sample can be obtained. In addition, elastic bright field images and diffraction patterns yield excellent resolution. Some applications of the method on multicomponent polymer materials are discussed.Bulk polymer samples were prepared by ultramicrotoming at room temperature or well below the glass transition temperature. Very thin films for the direct observation of the structure in semicrystalline polymers were obtained by melt-spinning. Specimens were examined with a ZEISS CEM 902 operated at 80 kV.

Kinetics of diffusion and sorption in aging processes of polymer materials (Review)

2021 ◽  
pp. 1-14
Author(s):  
A. A. Dalinkevich ◽  
◽  
L. V. Fomin ◽  
V. V. Melnikov ◽  
T. A. Nenasheva ◽  
...  
Keyword(s):  
Polymer Materials ◽  
Kinetics Of

scholarly journals Direct mapping of fiber diffraction patterns into reciprocal space

2009 ◽  
Vol 42 (2) ◽  
pp. 295-301 ◽  
Author(s):  
Norbert Stribeck ◽  
Ulrich Nöchel
Keyword(s):  
Direct Method ◽  
Reciprocal Space ◽  
Polymer Materials ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
Direct Mapping ◽  
Fiber Diffraction ◽  
Mapping Parameters ◽  
Diffraction Patterns ◽  
A Direct Method

On the basis of the concept of Polanyi [Z. Phys.(1921),7, 149–180], the mapping of fiber diffraction patterns into reciprocal space is revisited. The result is a set of concise mapping relations that does not contain any approximations. This set permits the design of a direct method that, in principle, does not require refinement of mapping parameters even for patterns of tilted fibers. The method is unsuitable for diffuse scattering patterns. If inaccuracies of two pixels can be tolerated, a pattern is automatically mapped into reciprocal space in real time. The method is proposed for the processing of the extensive sets of patterns that are recorded in time-resolved wide-angle X-ray diffraction investigations of polymer materials.

scholarly journals The Toxicological Testing and Thermal Decomposition of Drive and Transport Belts Made of Thermoplastic Multilayer Polymer Materials

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2232 ◽  
Author(s):  
Piotr Krawiec ◽  
Łukasz Warguła ◽  
Daniel Małozięć ◽  
Piotr Kaczmarzyk ◽  
Anna Dziechciarz ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Degradation Kinetics ◽  
Combustion Products ◽  
Polymer Materials ◽  
Toxic Substances ◽  
Butadiene Rubber ◽  
Different Temperatures ◽  
Increasing Temperature ◽  
In Fire ◽  
Kinetics Of

The article presents the potential impact of flat drive and transport belts on people’s safety during a fire. The analysis distinguished belts made of classically used fabric–rubber composite materials reinforced with cord and currently used multilayer polymer composites. Moreover, the products’ multilayers during the thermal decomposition and combustion can be a source of emissions for unpredictable and toxic substances with different concentrations and compositions. In the evaluation of the compared belts, a testing methodology was used to determine the toxicometric indicators (WLC50SM) on the basis of which it was possible to determine the toxicity of thermal decomposition and combustion products in agreement with the standards in force in several countries of the EU and Russia. The analysis was carried out on the basis of the registration of emissions of chemical compounds during the thermal decomposition and combustion of polymer materials at three different temperatures. Moreover, the degradation kinetics of the polymeric belts by using the thermogravimetric (TGA) technique was evaluated. Test results have shown that products of thermal decomposition resulting from the neoprene (NE22), leder leder (LL2), thermoplastic connection (TC), and extra high top cower (XH) belts can be characterized as moderately toxic or toxic. Their toxicity significantly increases with the increasing temperature of thermal decomposition or combustion, especially above 450 °C. The results showed that the belts made of several layers of polyamide can be considered the least toxic in fire conditions. The TGA results showed that NBR/PA/PA/NBR belt made with two layers of polyamide and the acrylonitrile–butadiene rubber has the highest thermal stability in comparison to other belts.

Kinetics of interaction of palm ethyl biodiesel with three different polymer materials

2008 ◽  
Vol 21 (12) ◽  
pp. 1068-1071 ◽  
Author(s):  
Giselle Lutz ◽  
Julio F. Mata-Segreda
Keyword(s):  
Polymer Materials ◽  
Kinetics Of

Adsorption of toluene from the mixed water−toluene system on medicinal activated carbon

2014 ◽  
Vol 92 (5) ◽  
pp. 392-396
Author(s):  
Igor Winkler ◽  
Volodymyr Diychuk
Keyword(s):  
Experimental Investigation ◽  
Activated Carbon ◽  
Adsorption Kinetics ◽  
Surface Adsorption ◽  
Equilibrium Concentration ◽  
Coal Surface ◽  
Adsorption Model ◽  
Insufficient Amount ◽  
Mixed Water ◽  
Kinetics Of

An experimental investigation of adsorption of toluene from the aqueous phase on medicinal activated carbon revealed that the process runs by the mechanism of preactivated adsorption. Kinetics of the initial stages of adsorption can be adequately represented by the empirical Elovich adsorption model. An insufficient amount of the adsorbent can cause an unexpected jump in the toluene equilibrium concentration in water caused by transferring this substance from the toluene phase into water through the process of additional adsorption on the coal surface. Adsorption constants and “imaginary” adsorption values have been determined for a series of toluene contents.

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