Kinetics of crack development in polymer materials

1968 ◽  
Vol 4 (11) ◽  
pp. 69-75 ◽  
Author(s):  
A. A. Kaminskii
Keyword(s):  
Crack Development ◽  
Polymer Materials ◽  
Kinetics Of

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 Features of destruction of a ferrite-martensitic composite

2018 ◽  
Vol 226 ◽  
pp. 03006 ◽  
Author(s):  
Viktor N. Pustovoit ◽  
Valentina V. Duka ◽  
Yuri V. Dolgachev ◽  
Ludmila P. Aref’eva ◽  
Vladislav V. Fedosov ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Composite Structure ◽  
Crack Development ◽  
Cyclic Tests ◽  
Rate Of Development ◽  
Crack Motion ◽  
The Matrix ◽  
Kinetics Of

The behavior of a crack in steel with the structure of a ferriticmartensitic composite is studied. The modes of heat treatment for obtaining a composite structure with alternating layers of ferrite and martensite are given. The kinetics of crack development during cyclic tests was studied. The obtained data show that the rate of development of the crack in the material with the structure of the composite is substantially lower than for the usual sorbite structure. It is shown that the frontal growth of the crack in the composite is carried out with “stops”, on which the matrix deforms and its stratification occurs in the direction normal to the front of the crack motion.

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

scholarly journals Synergism of the action of some stabilisers against the destruction of polymer materials

2021 ◽  
Vol 273 ◽  
pp. 04014
Author(s):  
Irina Zhukova ◽  
Evgeniya Flik ◽  
Elena Shubina ◽  
Vladimir Mishurov ◽  
Ivan Kashparov
Keyword(s):  
Synergistic Effect ◽  
Joint Action ◽  
Oxidative Degradation ◽  
Nitroxyl Radicals ◽  
Polymer Materials ◽  
Thermal Oxidative Degradation ◽  
Destructive Process ◽  
Positive Action ◽  
Presence And Absence ◽  
Kinetics Of

The process of thermal-oxidative degradation of polymer materials has been studied on the example of polyethylene in the presence of quinones and / or nitroxyl radicals. The synergistic effect of the positive action of a mixture of stabilisers from a number of quinones and nitroxyl radicals on the destructive process of polyethylene has been established. It has been shown that the rate of degradation has significantly slowed down when an equimolecular mixture of 4-acetylamino-2,2,6,6-tetramethylhexahydropyridine-1-oxyl and 2,6-di-tert-amyl-1,4-cyclohexadienone inhibitors has been introduced into the polymer. The kinetics of the initiated thermo-destructive process of polyethylene oxidation in the presence and absence of stabilisers has been studied. A mechanism of joint action of stabilisers based on their interaction with radicals and the breakage of radical chains, as well as a mechanism for the regeneration of stabilisers, has been proposed.

Quantitative Assessment of the Kinetics of Damage Accumulation in the Polymer Matrix Structure Under Full-Scale Climatic Factors and Tensile Loads

2021 ◽  
pp. 93-102
Author(s):  
В. П. Селяев ◽  
Д. Р. Низин ◽  
Н. С. Канаева
Keyword(s):  
Damage Accumulation ◽  
Climatic Factors ◽  
Full Scale ◽  
Polymer Materials ◽  
Strength Performance ◽  
Deformation Curves ◽  
Epoxy Polymers ◽  
Specific Index ◽  
Accumulation Kinetics ◽  
Kinetics Of

Постановка задачи. Изучено изменение упруго-прочностных показателей и кинетики накопления повреждений в эпоксидных полимерах под действием растягивающих нагрузок в контрольном состоянии и после натурного климатического воздействия в течение одного календарного года. Расчет кинетики накопления повреждений осуществлялся на основе авторской методики, основанной на использовании методов фрактального анализа кривых деформирования образцов полимерных материалов при растяжении. Результаты. Предложен удельный показатель θ, позволяющий количественно оценивать суммарное число повреждений на единицу прочности, накопление которого приводит к разрушению полимеров. Получены аппроксимирующие зависимости, описывающие взаимосвязь между удельным показателем θ и пределом прочности эпоксидных полимеров при растяжении. Выводы. Установлено, что наибольшей стабильностью свойств под действием натурного климатического воздействия обладает полимер на основе эпоксидной смолы «Этал-247». Statement of the problem. In the current study we look at the change in the elastic-strength performance and kinetics of damage accumulation in epoxy polymers under tensile loads in the control state and after full-scale climatic exposure during one calendar year were studied. Damage accumulation kinetics was calculated based on the author's method using methods of fractal analysis of deformation curves for polymer materials samples under tension. Results. We proposed specific index θ to quantify the total number of damages per unit of strength where its accumulation leads to the destruction of polymers. The dependences have been obtained that describe the relationship between specific index θ and tensile strength of epoxy polymers. Consclusion. The study has shown that the Etal-247 epoxy resin-based polymer cured with Etal-1440 amine hardener has the most stable properties under the full-scale climatic exposure.

scholarly journals Concepts of Nucleation in Polymer Crystallization

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 304
Author(s):  
Jun Xu ◽  
Günter Reiter ◽  
Rufina G. Alamo
Keyword(s):  
Polymer Crystallization ◽  
Vital Role ◽  
Polymer Chains ◽  
Polymer Materials ◽  
Crystal Nucleation ◽  
The Past ◽  
Open Questions ◽  
Lamellar Crystals ◽  
Kinetics Of ◽  
Complex Subject

Nucleation plays a vital role in polymer crystallization, in which chain connectivity and thus the multiple length and time scales make crystal nucleation of polymer chains an interesting but complex subject. Though the topic has been intensively studied in the past decades, there are still many open questions to answer. The final properties of semicrystalline polymer materials are affected by all of the following: the starting melt, paths of nucleation, organization of lamellar crystals and evolution of the final crystalline structures. In this viewpoint, we attempt to discuss some of the remaining open questions and corresponding concepts: non-equilibrated polymers, self-induced nucleation, microscopic kinetics of different processes, metastability of polymer lamellar crystals, hierarchical order and cooperativity involved in nucleation, etc. Addressing these open questions through a combination of novel concepts, new theories and advanced approaches provides a deeper understanding of the multifaceted process of crystal nucleation of polymers.

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