Using the retraction method of a deformed drop, the interfacial tension between polypropylene (PP) and two different molten metals (tin and the eutectic SnAgCu alloy) has been measured at 250 and 230 °C, respectively. Systematic rheological investigations of the materials under study enabled us to measure the viscosity of the polymer matrix and that of the metal liquids. A viscosity of 1.9 and 2 mPa s in the melt is reported for the tin and SnAgCu alloys, respectively. Based on these investigations, the interfacial tension between the molten metals and the polymer matrix is determined for the first time. The influence of the polymer matrix viscoelasticity and liquid metal surface oxidation is analyzed in order to determine the most accurate conditions for measuring the interfacial tension between the polymer and the liquid metal. Values as high as 350 mN m⁻¹ (for PP/SnAgCu) and 140 mN m⁻¹ (PP/tin) are reported, indicating a poor affinity between the molten metal and the polymer matrix. By temperature quenching, the dispersion of the liquid metal drops in the polypropylene under constant shear, and the formation of solid metal ellipsoids is obtained, with a characteristic size that is limited by the critical deformation parameter defined by Taylor. Our study, thus, offers an experimental approach of measuring the interfacial tension between two highly incompatible liquids, opening at the same time a promising perspective for obtaining, by a rheological approach, metal particles with a non-negligible form factor.

中文翻译：

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聚丙烯基体中熔融金属的液滴松弛：界面张力的测量

使用变形液滴的回缩方法，分别在250和230°C下测量了聚丙烯（PP）与两种不同的熔融金属（锡和共晶SnAgCu合金）之间的界面张力。对所研究材料的系统流变学研究使我们能够测量聚合物基体和金属液体的粘度。据报道，锡和SnAgCu合金的熔体粘度分别为1.9 mPa s和2 mPa s。基于这些研究，首次确定了熔融金属和聚合物基体之间的界面张力。分析聚合物基质粘弹性和液态金属表面氧化的影响，以便确定用于测量聚合物与液态金属之间的界面张力的最准确条件。报道了^-1（对于PP / SnAgCu）和140 mN m ^-1（PP /锡），表明熔融金属和聚合物基体之间的亲和力很差。通过温度淬火，液态金属的分散液在恒定剪切力下滴落在聚丙烯中，并形成了固态金属椭圆体，其特征尺寸受到泰勒定义的临界变形参数的限制。因此，我们的研究提供了一种测量两种高度不相容的液体之间的界面张力的实验方法，同时为流变方法获得形状因子不可忽略的金属颗粒提供了广阔的前景。