Fracture behavior in nylon 6 fibers
Fracture behavior in nylon 6 fibers
复制标题
尼龙 6 纤维的断裂行为
DOI：
10.1002/pol.1972.160100802
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发表时间：
1972
期刊：
影响因子：
--
通讯作者：
M. Williams
中科院分区：
文献类型：
--
作者：
B. A. Lloyd;K. Devries;M. Williams
描述了聚合物纤维断裂的反应速率模型。该模型假设键断裂是由绝对反应速率理论与应力辅助活化能。结果表明，模型与实验吻合良好的关键在于合理地考虑了系链分子所受应力的变化。较紧的链条首先断裂，载荷在其余未断裂的系链中重新分配。探讨了在模型和实验中改变温度对纤维断裂的影响。只有在不确定系链上的应力分布的情况下，模型的预测与实验结果才可能吻合得很好。通过电子顺磁共振（EPR）光谱监测键断裂的动力学，在实验上确定的链上的应力分布。发现温度对宏观强度有两种影响。(1)热能有助于原子应力破坏原子键;因此，在给定的分子应力下，键族的键断裂速率增加。在这方面，温度可被视为降低键的“强度”。(2)温度还起到“松弛”分子结构的作用，并以这种方式改变连接链上的应力分布。为了定量地解释粘结断裂和宏观断裂行为，必须考虑这两种效应。
A reaction rate model of fracture in polymer fibers is described. This model assumes that bond rupture is governed by absolute reaction rate theory with a stress-aided activation energy. It is demonstrated that the key in obtaining good agreement between the model and experiment lies in taking proper account of the variation of stress on the tie-chain molecules. The more taut chains rupture first, and the load is redistributed among the remaining unruptured tie chains. The effect of varying the temperature both in the model and in experiments on fracture in fibers is explored. Good agreement between predictions of the model and experiment is possible only with an undeterstanding of the distribution in stress on the tie chains. The distribution in stress on the chains was experimentally determined by monitoring the kinetics of bond rupture with electron paramagnetic resonance (EPR) spectroscopy. Temperature is found to have two effects on macroscopic strength. (1) The thermal energy aids the atomic stress in breaking the atomic bonds; as a consequence the rate of bond rupture of a family of bonds under a given molecular stress is increased. In this respect temperature might be viewed as decreasing the “strength” of a bond. (2) Temperature also serves to “loosen” the molecular structure and in this way modify the distribution in stress on the tie chains. To explain bond rupture and macroscopic fracture behavior quantitatively, account must be taken of both effects.