The stress response of polymer double networks depends not only on the properties of the constituent networks but also on the interactions arising between them. Here, we demonstrate, via coarse-grained simulations, that both their global stress response and their microscopic fracture mechanics are governed by load sharing through these internetwork interactions. By comparing our results with affine predictions, where stress redistribution is by definition homogeneous, we show that stress redistribution is highly inhomogeneous. In particular, the affine prediction overestimates the fraction of broken chains by almost an order of magnitude. Furthermore, homogeneous stress distribution predicts a single fracture process, while in our simulations, fracture of sacrificial chains takes place in two steps governed by load sharing within a network and between networks, respectively. Our results thus provide a detailed microscopic picture of how inhomogeneous stress redistribution after rupture of chains governs the fracture of polymer double networks.

中文翻译：

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分担负载：应力重新分布控制聚合物双网络的断裂

聚合物双网络的应力响应不仅取决于组成网络的性质，还取决于它们之间产生的相互作用。在这里，我们通过粗粒度模拟证明，它们的全局应力响应和它们的微观断裂力学都受通过这些互联互通相互作用的负载共享控制。通过将我们的结果与仿射预测进行比较，其中应力重新分布根据定义是均匀的，我们表明应力重新分布是高度不均匀的。特别是，仿射预测高估了断裂链的比例几乎一个数量级。此外，均匀的应力分布预测了单个断裂过程，而在我们的模拟中，牺牲链的断裂分两个步骤发生，分别由网络内和网络之间的负载共享控制。因此，我们的结果提供了详细的微观图片，说明链断裂后不均匀的应力重新分布如何控制聚合物双网络的断裂。