Mechanisms of deformation in crystallizable natural rubber. Part 1: Thermal characterization

POLYMER

卷:54

Article

Samaca Martinez, J. R.^1,2,3  Le Cam, J. -B.⁴  Balandraud, X.^2,5  Toussaint, E.^1,2  Caillard, J.³ 

[1] Univ Blaise Pascal, Clermont Univ, Inst Pascal, F-63000 Clermont Ferrand, France

[2] Inst Pascal, CNRS, UMR 6602, F-63171 Aubiere, France

[3] Michelin, Cerl Ladoux, F-63040 Clermont Ferrand, France

[4] Univ Rennes 1, Larmaur ERL CNRS 6274, F-35042 Rennes, France

[5] Clermont Univ, Inst Francais Mecan Avancee, Inst Pascal, F-63000 Clermont Ferrand, France

关键词: Natural rubber;    Stress-induced crystallization;    Deformation mechanisms;   

DOI  :  10.1016/j.polymer.2013.03.011

来源: Elsevier

【 摘 要 】

This paper investigates the mechanisms of deformation in rubber, especially stress-induced crystallization, using infrared thermography. Temperature variations are measured during cyclic uniaxial mechanical tests at ambient temperature. Results show that natural rubber mainly exhibits entropic behaviour: the material produces (resp. absorbs) heat during loading (resp. unloading). The crystallization of the polymer chains under tension leads to a temperature increase of the order of several degrees Celsius. If crystallization and crystallite melting occur over one mechanical cycle, a hysteresis loop is observed in terms of the strain stress relationship. Stress relaxation tests show that the thermal signatures of crystallization and of crystallite melting are different. Indeed, if the strain is maintained fixed during loading, the temperature continues to increase for a few seconds before returning to the ambient temperature. This reveals that crystallization continues during relaxation. On the contrary, if the strain is maintained fixed during unloading, the specimen returns instantaneously to the ambient temperature. (C) 2013 Elsevier Ltd. All rights reserved.

【 授权许可】

Free