Abstract A numerical simulation for foaming a melted thermoplastic by extrusion process is conducted, where thermo-expandable microcapsules are used as a blowing agent. Firstly, a growth model for an encapsulated bubble is developed to match experimental results. Then, the growth model is used to numerically solve a 2D non-isothermal die-swell problem, making possible to simulate the extrusion foaming process. In particular, the model is able to predict the foaming location. Numerical results are compared with experimental data obtained by optical microscopy observations and density measurements on extruded samples. The effects of thermoplastic melt rheology on foaming and the die swell induced by foaming are also investigated. This simulation helps to estimate process parameters such as extrusion speed and to predict die swell and sample porosity in whole, to finally optimize the industrial process.

中文翻译：

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具有热膨胀性微胶囊的热塑性发泡：挤出过程的数学建模和数值模拟

摘要 以热膨胀性微胶囊为发泡剂，对熔融热塑性塑料进行挤出发泡数值模拟。首先，开发了封装气泡的生长模型以匹配实验结果。然后，生长模型用于数值求解二维非等温模具膨胀问题，从而可以模拟挤出发泡过程。特别是，该模型能够预测发泡位置。将数值结果与通过光学显微镜观察和挤出样品密度测量获得的实验数据进行比较。还研究了热塑性熔体流变学对发泡和发泡引起的模头膨胀的影响。