scholarly journals Synthesis and study of aroylethyl(ethyl)-xanthates as stabilizers of polymeric materials

2021 ◽  
Author(s):  
Tanzila Akchurina ◽  
Sabira Sardarova ◽  
Khuraman Efendiyeva ◽  
Irada Eyvazova ◽  
Vagif Farzaliyev ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Intermediate Product ◽  
Cumene Hydroperoxide ◽  
Polymeric Materials ◽  
Transformation Products ◽  
Oxidative Destruction ◽  
Ethyl Xanthate ◽  
Stabilizing Effect ◽  
Oxidation Chain ◽  
Thermal Stability Of

AbstractThe number of aroylethyl (ethyl)xanthates have been synthesized by the reaction of the exchange decomposition of β-dimethylaminopropiophenone hydrochlorides with potassium xanthate containing several functional groups (C=O, C=S, C–OH), which determine the use of these xanthates as stabilizers with internal synergy to polymeric materials. It was shown that the thermal stability of the compounds, depending on the nature of the substituent in the benzene ring of the molecule was observed in the temperature range of 149–196 °C. It was revealed that aroylethyl(ethyl)xanthates had a stabilizing effect due to the suppression of thermo-oxidative destruction of polyethylene; they increased the induction period of polyethylene oxidation by 2–6 times, and the oxidation rate was reduced by about 3–9 times. Among the studied compounds, 4-hydroxybenzoylethyl (ethyl)xanthate had the greatest stabilizing effect. The study of the mechanism of the stabilizing action of the compounds showed that xanthates react with cumene hydroperoxide (CHP), which proceeded through the stage of formation of an intermediate product that actively decomposed CHP, i.e., the oxidation chain was terminated by the decomposition of the CHP not by the initial xanthates but by their transformation products.

scholarly journals Anionic surfactant sulfate dodecyl sodium (SDS)-induced thermodynamics and conformational changes of collagen by ultrasensitive microcalorimetry

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Jie Zhang ◽  
Chunhua Wang ◽  
Fengteng Zhang ◽  
Wei Lin
Keyword(s):  
Thermal Stability ◽  
Conformational Changes ◽  
Triple Helix ◽  
Striking Difference ◽  
Thermal Transition ◽  
Scanning Calorimetry ◽  
Helix Structure ◽  
Stabilizing Effect ◽  
Collagen Molecules ◽  
Thermal Stability Of

Abstract In this communication, sulfate dodecyl sodium (SDS)-induced thermodynamics and conformational changes of collagen were studied. We used ultrasensitive differential scanning calorimetry (US-DSC) to directly monitor the thermal transition of collagen in the presence of SDS. The results show that SDS affects the conformation and thermal stability of collagen very differently depending on its concentrations. At CSDS ≤ 0.05 mM, the enhanced thermal stability of collagen indicates the stabilizing effect by SDS. However, a further increase of SDS leads to the denaturation of collagen, verifying the well-known ability of SDS to unfold proteins. This striking difference in thermodynamics and conformational changes of collagen caused by SDS concentrations can be explained in terms of their interactions. With increasing SDS, the binding of SDS to collagen can be dominated by electrostatic interaction shifting to hydrophobic interaction, and the latter plays a key role in loosening and unfolding the triple-helix structure of collagen. The important finding in the present study is the stabilizing effect of SDS on collagen molecules at extreme low concentration. Graphical abstract

TGA as a Tool for Studying the Thermal Stability of Polymeric Materials

2004 ◽  
Vol 455-456 ◽  
pp. 463-466 ◽  
Author(s):  
Carla Leer ◽  
Gabriela Botelho ◽  
Pieter Gijsman
Keyword(s):  
Thermal Stability ◽  
Polymeric Materials ◽  
Thermal Stability Of

Structural investigation and thermal stability of new extruded wheat flour based polymeric materials

2008 ◽  
Vol 73 (4) ◽  
pp. 548-557 ◽  
Author(s):  
Nathalie Leblanc ◽  
Redouan Saiah ◽  
Eric Beucher ◽  
Richard Gattin ◽  
Michel Castandet ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Wheat Flour ◽  
Structural Investigation ◽  
Polymeric Materials ◽  
Thermal Stability Of

Polymer Nanocomposite Development for Electronic Industry Needs

2009 ◽  
Vol 151 ◽  
pp. 3-9 ◽  
Author(s):  
Jari Koskinen ◽  
Mikko Karttunen ◽  
Mika Paajanen ◽  
Juha Sarlin
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Polymeric Materials ◽  
Polymer Nanocomposite ◽  
Polymer Materials ◽  
Research Centre ◽  
Electronic Industry ◽  
Application Potential ◽  
Industry Needs ◽  
Thermal Stability Of

The properties of polymeric materials have been enhanced by developing nanocomposites in several projects at the Technical Research Centre of Finland VTT. The improvement of conductivity, dielectric, mechanical properties and the thermal stability of polymer materials opens new application potential in electronic industry. In this paper the results of several projects are presented. By applying nano-POSS particles in polypropylene and epoxy the break down voltage was increased by 10 - 20%. The use of carbon nanotubes in polyaniline enhanced the conductivity by two decades compared to the commercially available polymers.

scholarly journals THE THERMAL STABILITY OF POLYMER CABLE COMPOUNDS WITH A FLAME-RETARDING FILLER

2018 ◽  
Vol 13 (6) ◽  
pp. 35-41
Author(s):  
A. Yu. Svatikov ◽  
I. D. Simonov-Emelyanov
Keyword(s):  
Thermal Stability ◽  
Flame Retardant ◽  
Magnesium Hydroxide ◽  
Fire Safety ◽  
Polymeric Materials ◽  
Crystalline Hydrate ◽  
Pressure Casting ◽  
Volatile Products ◽  
Halogen Free ◽  
Thermal Stability Of

Currently, halogen-free cable compositions are becoming increasingly common in the manufacture of cable compositions. The concept of halogen-free or “zero halogen” becomes a symbol of fire resistance, low-smoke characteristics, low toxicity of volatile products of combustion, the absence of the toxic, corrosive and irritating gas - hydrogen chloride - and other hydrogen halides in the volatile products. More and more manufacturers of cable products are beginning to pay increasing attention to the problems of processing, toxicity and fire safety. It should be noted that the requirements for improving the fire safety of cable products are constantly becoming tougher, since the main problem of most of these polymeric materials is their flammability, high smoke generation and high flame spread rate. In this regard, there is a burning question to increase these characteristics and bring them to the level of compounds based on PVC. The main way to increase the flame-retardant characteristics of halogenfree cable compositions is to introduce mineral fire retardants into these compositions. The study of the composition and packaging of these mineral fillers-flame retardants makes it possible to increase the level of flame-retardant characteristics of halogen-free cable compositions. The paper presents the results of studies on the thermal stability of cable compositions based on PE + EVA mixtures containing magnesium hydroxide crystalline hydrate as a filler-flame retardant. It is shown that cable compositions containing magnesium hydroxide crystal hydrate are characterized by higher heat resistance and thermal stability (~ 2-fold) compared to a polymeric matrix based on PE + SEVA. This allows to process them at high temperatures (more than 200°C) by extrusion and pressure casting.

scholarly journals UV Polymerization of Methacrylates—Preparation and Properties of Novel Copolymers

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1659
Author(s):  
Marta Worzakowska
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Methyl Methacrylate ◽  
Chemical Resistance ◽  
Polymeric Materials ◽  
Monomer Content ◽  
Methacrylate Monomer ◽  
Methacrylate Monomers ◽  
Thermal Stability Of ◽  
Citronellyl Methacrylate

More environmentally friendly polymeric materials for use in corrosive conditions were obtained in the process of UV polymerization of terpene methacrylate monomers: geranyl methacrylate and citronellyl methacrylate and the commercially available monomer methyl methacrylate. Selected properties (solvent resistance, chemical resistance, glass transition temperature, thermal stability, and decomposition course during heating) were evaluated. It was found that the properties of the materials directly depended on the monomer percentage and the conditioning temperatures used. An increase in the geranyl or citronellyl methacrylate monomer content in the copolymers reduced the solubility and chemical resistance of the materials post-cured at 50 °C. The samples post-cured at 120 °C were characterized by high resistance to polar and non-polar solvents and the chemical environment, regardless of the percentage composition. The glass transition temperatures for samples conditioned at 120 °C increased with increasing content of methyl methacrylate in the copolymers. The thermal stability of copolymers depended on the conditioning temperatures used. It was greater than 200 °C for most copolymers post-cured at 120 °C. The process of pyrolysis of copolymers led to the emission of geranyl methacrylate, citronellyl methacrylate, and methyl methacrylate monomers as the main pyrolysis volatiles.

Thermal Stability of Polyurethane Coating Prepared by Using Diphenylolpropane

2021 ◽  
Vol 899 ◽  
pp. 739-744
Author(s):  
Indira N. Bakirova ◽  
Svetlana E. Mitrofanova
Keyword(s):  
Thermal Stability ◽  
Temperature Region ◽  
Polymer Structure ◽  
Phenolic Hydroxyl ◽  
Polyurethane Coating ◽  
Thermooxidative Degradation ◽  
Stabilizing Effect ◽  
Varnish Coating ◽  
Higher Temperature ◽  
Thermal Stability Of

Thermal stability on air of polyurethane varnish coating prepared from diphenylolpropane, polyetherpolyol and polyisocyanate was assessed. The presence of urethane groups, formed by phenolic hydroxyl of diphenylolpropane, in the polymer structure was shown to decrease its thermooxidative degradation onset temperature. At the same time, deceleration of thermooxidative processes due to stabilizing effect of diphenylolpropane released at the beginning of thermal decay of polyurethane is observed in the higher temperature region.

scholarly journals Synthesis, Characterization, and Thermal Behavior of Nanoparticles of Mg(OH)2 to Be Used as Flame Retardants

2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
A. A. Hanna ◽  
A. S. Abdelmoaty ◽  
M. A. Sherief
Keyword(s):  
Thermal Stability ◽  
Flame Retardant ◽  
Flame Retardants ◽  
Hexagonal Phase ◽  
Polymeric Materials ◽  
Prepared Material ◽  
Different Shapes ◽  
Thermal Stability Of ◽  
Volatile Materials

To study the effects of the precursor materials on the structure, the morphology, and the thermal stability of Mg(OH)2 particles, five samples were prepared by using the same method. The produced powder was characterized by using FTIR, XRD, SEM, and TEM, and the thermal stability was studied by using the thermogravimetric analysis. This study aims to use the advantage prepared material as a flame-retardant for the polymeric materials. The characterization of the obtained samples shows that Mg(OH)2 is formed in hexagonal phase and arranged in different shapes. The analysis of the data obtained from the TGA shows that Mg(OH)2 in general decomposed in three steps, the first one due to the water content and the other volatile materials, the second step represents the decomposition of Mg(OH)2 to produce MgO, and the third step represents the conversion of MgO to glassy layer. The samples prepared in presence of the surfactants gave a higher value for the formation of the glassy layer so that it is recommended to use this sample as flame retardant for the polymeric materials.

THE EFFECT OF ION CONCENTRATION AND pH ON THE THERMAL STABILITY OF A CANINE ADENOVIRUS

1967 ◽  
Vol 13 (9) ◽  
pp. 1139-1149 ◽  
Author(s):  
T. Yamamoto
Keyword(s):  
Thermal Stability ◽  
Salt Solution ◽  
Ion Concentration ◽  
Ph Adjustment ◽  
Ion Concentrations ◽  
Stabilizing Effect ◽  
High Concentrations ◽  
Ph Range ◽  
Thermal Stability Of

The inactivation of a canine adenovirus hemagglutinin and infectivity at 56 °C at varying times up to 1 h has been studied in the presence of various ions and concentrations of ions.Under conditions of uncontrolled pH 1–2 M NaCl and MgCl2 both stabilized the virus hemagglutinin and infectivity. Lower concentrations of these salts as well as 0.04 M phosphate, Hank's balanced salt solution, and minimal Eagle's medium had little stabilizing effect. Molar concentrations of phosphate and Tris butter were also found to stabilize the virus hemagglutinin.The pH adjustment of the suspending salt solution was found to be important since high concentrations of salts such as MgCl2 are quite acidic. Both 1 M MgCl2 and 1 M NaCl stabilized the virus in the pH range of 4–6, but inactivation was rapid at pH 3 and less rapid at pH 7. Ion concentrations lower than 1 M markedly reduced the hemagglutinin stabilization at optimun pH.

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