Frictional behaviour of aged natural rubber

Kód výsledku v IS VaVaI

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Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Frictional behaviour of aged natural rubber

Popis výsledku v původním jazyce

The growing interest for aging of rubber vulcanizates starts from early 1945, when Symposium on the physical and chemical breakdown of rubbers was organized in Birmingham, England. Historically, attention has been given to changes in tensile strength resulting from conditioning of rubber at elevated temperatures for specified periods of time. During the time, rubber typically becomes harder and loses its flexibility and fatigue. The aging process is a chemical change of material due to thermodynamic reaction, which strongly affects all mechanical properties and in the end determine life time of product. In the present work, sulphur cured natural rubber (NR) sheet of 2 mm thickness was thermally aged at 90°C for 30 days. The main goal was to study the frictional behavior of aged NR at different tribological testing parameters such as friction speed and load. Friction is the surface interaction in moving contact between frictional partners. The tribological mechanism in rubber are quite different than mechanisms involved in hard materials like metals or ceramics. Is well known, that during hard ball sliding on soft rubber surface, regular folds are created in direction of motion as a result of complicated compression-tension distribution around the contact area. Besides friction coefficient, wear is also an important behaviour of any rubber composites. Friction wear usually is a combination of several parameters which include the contact pressure, temperature, and sliding velocity. Contrasting to the sliding wear of hard materials, elastomers involve complex wear mechanisms, which are affected by “waves of detachment” apparition and create characteristic abraded surface. It was found that ageing generally decrease friction coefficient of investigated samples and significantly increase wear. Coefficient of Friction (COF) displayed essential decreasing for all studied samples when applied load rise. If sliding speed increase, then COF became bigger. In contrast, wear increase for higher load and higher speed.

Název v anglickém jazyce

Frictional behaviour of aged natural rubber

Popis výsledku anglicky

The growing interest for aging of rubber vulcanizates starts from early 1945, when Symposium on the physical and chemical breakdown of rubbers was organized in Birmingham, England. Historically, attention has been given to changes in tensile strength resulting from conditioning of rubber at elevated temperatures for specified periods of time. During the time, rubber typically becomes harder and loses its flexibility and fatigue. The aging process is a chemical change of material due to thermodynamic reaction, which strongly affects all mechanical properties and in the end determine life time of product. In the present work, sulphur cured natural rubber (NR) sheet of 2 mm thickness was thermally aged at 90°C for 30 days. The main goal was to study the frictional behavior of aged NR at different tribological testing parameters such as friction speed and load. Friction is the surface interaction in moving contact between frictional partners. The tribological mechanism in rubber are quite different than mechanisms involved in hard materials like metals or ceramics. Is well known, that during hard ball sliding on soft rubber surface, regular folds are created in direction of motion as a result of complicated compression-tension distribution around the contact area. Besides friction coefficient, wear is also an important behaviour of any rubber composites. Friction wear usually is a combination of several parameters which include the contact pressure, temperature, and sliding velocity. Contrasting to the sliding wear of hard materials, elastomers involve complex wear mechanisms, which are affected by “waves of detachment” apparition and create characteristic abraded surface. It was found that ageing generally decrease friction coefficient of investigated samples and significantly increase wear. Coefficient of Friction (COF) displayed essential decreasing for all studied samples when applied load rise. If sliding speed increase, then COF became bigger. In contrast, wear increase for higher load and higher speed.

Druh

O - Ostatní výsledky

CEP obor

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OECD FORD obor

10404 - Polymer science

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů