Abstract Polymers with special properties (e.g. electrical, optical or mechanical) are often obtained via the addition of fillers. The composites' final properties rely on the preservation of these fillers during blending, which is, in particular, challenging for high aspect ratio particles, like shear-sensitive flaky particles (ssFP). Thus, in cases of ssFP off- or in-line monitoring is indicated. This study addresses the lack of suitable non-destructive monitoring methods appropriate for ssFP possessing a thickness below 1 μ m and an area equivalent diameter of several 10 μ m . An elegant method was developed to validate the integrity of ssFP within composites, which is based on the measurement of the composites' permittivity and applying precise micro-structure property correlations to indirectly determine the fillers' morphological features. The main hypothesis tested was that a reduction of the particles aspect ratio by a factor of larger than 5 can be detected by the measurement of the composites' permittivity. In this study, polyethylene or epoxy resin were blended with the mica-based ssFP Iriodin 153 which features a mean area equivalent diameter of 42 μ m and an average thickness of about 1 μ m . The micro-structure property correlation presented by G. Ondracek [Z. f. Werkstofftechnik, 8:280-287, 1977] provided the necessary theoretical backbone to indirectly infer geometrical changes to the ssFP from permittivity measurements of the composite. An excellent match was obtained between the indirectly (permittivity measurements) and the directly (ashing of matrix and subsequent scanning electron microscopy) determined particles' aspect ratios which related directly to the particles' area equivalent diameter because the thickness of the particles was almost constant. This preliminary study established the presented technique as a promising non-destructive test method to monitor the integrity of ssFPs embedded in polymers. In principle this technique is adaptable for in-line process monitoring.

中文翻译：

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通过非破坏性介电常数测量对聚合物颗粒复合材料中的颗粒进行间接形态分析

摘要 通常通过添加填料获得具有特殊性能（例如电学、光学或机械）的聚合物。复合材料的最终性能取决于混合过程中这些填料的保存，这对于高纵横比颗粒，如剪切敏感片状颗粒 (ssFP) 尤其具有挑战性。因此，在 ssFP 离线或在线监控的情况下被指示。这项研究解决了缺乏适合厚度低于 1 μm 和面积等效直径为几个 10 μm 的 ssFP 的合适的无损监测方法。开发了一种优雅的方法来验证复合材料中 ssFP 的完整性，该方法基于复合材料介电常数的测量，并应用精确的微观结构属性相关性来间接确定填料的 形态特征。测试的主要假设是，通过测量复合材料的介电常数，可以检测到颗粒纵横比降低了 5 倍以上。在这项研究中，聚乙烯或环氧树脂与云母基 ssFP Iriodin 153 混合，其平均面积等效直径为 42 μm，平均厚度约为 1 μm。G. Ondracek [Z. F。Werkstofftechnik, 8:280-287, 1977] 提供了必要的理论基础，可以从复合材料的介电常数测量中间接推断 ssFP 的几何变化。间接（介电常数测量）和直接（基质灰化和随后的扫描电子显微镜）确定的粒子之间获得了极好的匹配 纵横比与颗粒的面积等效直径直接相关，因为颗粒的厚度几乎是恒定的。这项初步研究将所提出的技术确立为一种很有前途的无损测试方法，以监测嵌入聚合物中的 ssFP 的完整性。原则上，该技术适用于在线过程监控。