Study of the microstructure evolution caused by the strain‐induced crystallization in polymers
Study of the microstructure evolution caused by the strain‐induced crystallization in polymers
复制标题
聚合物应变诱导结晶引起的微观结构演化研究
DOI：
10.1002/pamm.201800224
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Klinge
中科院分区：
文献类型：
--
作者：
Aygün;Klinge
聚合物（如天然橡胶）中的应变诱导结晶（SIC）是一种由高变形引起的自然增强现象。从拉伸测试中获得的实验数据表明，结晶开始于200 - 400%的应变，而在最大可能拉伸高达700%时，结晶度的体积分数达到最高程度。晶体区域的增大和减小引起应力-拉伸曲线的滞后，表明该过程具有耗散特性。在我们的工作中，所描述的材料行为是通过一个微力学连续体模型来模拟的，该模型涉及网络规则程度作为一个内部变量。重点研究了模拟循环加载过程中结晶度变化的耗散势公式。目前的方法进一步模拟了晶体取向和形态对外加载荷的依赖关系，这是通过假设非弹性变形和网络规则之间的特定耦合条件来实现的。
The strain‐induced crystallization (SIC) in polymers, such as in natural rubber, is a phenomenon manifesting itself as the natural reinforcement caused by the high deformation. Experimental data obtained from tensile tests show that the crystallization starts at a strain of 200‐400%, whereas, at maximum possible stretches of up to 700%, the volume fraction of the crystallinity reaches its highest degree. The growth and reduction of the crystalline regions cause a hysteresis in the stress‐stretch curve which indicates that the process has a dissipative character. In our work, the described material behavior is simulated by a micromechanical continuum model which involves the degree of network regularity as an internal variable. The focus is on the formulation of the dissipation potential simulating the change of the crystallinity degree during cyclic loading. The current approach furthermore simulates the dependence of the crystal orientation and form on the applied external load, which is achieved by assuming a specific coupling condition between the inelastic deformations and network regularity.