We consider an atomistic model of thermal welding at the polymer-polymer interface of a polyetherimide/polycarbonate blend, motivated by applications to 3D manufacturing in space. We follow diffusion of semiflexible chains at the interface and analyze strengthening of the samples as a function of the welding time tw by simulating the strain-stress and shear viscosity curves. The time scales for initial wetting, and for fast and slow diffusion, are revealed. It is shown that each component of the polymer blend has its own characteristic time of slow diffusion at the interface. Analysis of strainstress demonstrates saturation of the Young’s modulus at tw = 240 ns, while the tensile strength continues to increase. The shear viscosity is found to have a very weak dependence on the welding time for tw > 60 ns. It is shown that both strain-stress and shear viscosity curves agree with experimental data.

中文翻译：

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具有聚合物-聚合物界面的无定形聚合物共混物原子模型中的焊接动力学

我们考虑了聚醚酰亚胺/聚碳酸酯共混物的聚合物-聚合物界面处的热焊接原子模型，其动机是在空间 3D 制造中的应用。我们跟踪界面处半柔性链的扩散，并通过模拟应变-应力和剪切粘度曲线来分析样品的强化与焊接时间 tw 的关系。揭示了初始润湿以及快速和缓慢扩散的时间尺度。结果表明，聚合物共混物的每个组分在界面处都有其缓慢扩散的特征时间。应变应力分析表明杨氏模量在 tw = 240 ns 时饱和，而拉伸强度继续增加。发现剪切粘度对 tw > 60 ns 的焊接时间具有非常弱的依赖性。