Stress-Induced Crystallization around a Crack Tip in Natural Rubber
Stress-Induced Crystallization around a Crack Tip in Natural Rubber
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DOI：
10.1021/ma021106c
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发表时间：
2002-12
期刊：
影响因子：
5.5
通讯作者：
S. Trabelsi;P. Albouy;J. Rault
中科院分区：
文献类型：
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作者：
S. Trabelsi;P. Albouy;J. Rault
用X射线衍射法测量了顺式-1，4-聚异戊二烯低比拉伸样品的应力诱导结晶、取向和结晶度，λ<；3.5.观察到最大结晶度区和不同结晶度的过渡区；测量了裂纹尖端周围这些半晶区的尺寸，作为拉伸比、裂纹长度和交联剂密度的函数。建立了等晶度图，这使得人们可以测量局部拉伸比，然后测量裂纹尖端周围的局部应力。将裂纹尖端附近的应力分布与线性或非线性弹性理论预测的标度律进行了比较。最后，证明了在裂纹尖端、裂纹面和试件侧边之间存在一个松弛区域。这一区域的表面与裂纹尖端周围的半晶区面积和裂纹张开表面相当。
Stress-induced crystallization, orientation, and crystallinity have been measured by X-ray diffraction around cracks in a cis-1,4-polyisoprene sample drawn at low ratio, λ < 3.5. A zone of maximum crystallinity and a transition zone of varying crystallinity are observed; the dimensions of these semicrystalline zones surrounding the crack tip are measured as a function of the draw ratio, crack length, and cross-link density. An isocrystallinity map is established; this permits one to measure the local draw ratio and then the local stress around the crack tip. The stress distribution around the crack tip is compared with the scaling laws predicted by the linear or nonlinear elasticity theories. Finally, one shows the existence of a relaxed zone between the crack tip, the crack surface, and the lateral sides of the sample. The surface of this zone is comparable to the area of the semicrystalline zone around the crack tip and to the crack opening surface.