Sambale Anna Katharina, Maisl Michael, Herrmann Hans-Georg, Stommel Markus
Institute of Polymer Materials, Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Str. 6, D-01069 Dresden, Germany.
Fraunhofer Institute for Nondestructive Testing IZFP, Campus E3 1, D-66123 Saarbrücken, Germany.
Polymers (Basel). 2021 Sep 17;13(18):3141. doi: 10.3390/polym13183141.
Polyamide 6 (PA6) is able to absorb water from the surrounding air and bond to it by forming hydrogen bonds between the carbonamide groups of its molecular chains. Diffusion processes cause locally different water concentrations in the (component) cross-section during the sorption process, resulting in locally different mechanical properties due to the water-induced plasticisation effect. However, the water content of PA6 is usually specified as an integral value, so no information about a local water distribution within a component is provided. This paper shows a method to characterise moisture distributions within PA6 samples using low-energy computer tomography (CT) techniques and comparing the reconstructed results with a developed finite elements (FE) modelling method based on Fick's diffusion laws with concentration-dependent diffusion coefficients. For this purpose, the ageing of the samples at two different water bath temperatures as well as at different integral water contents are considered. The results obtained by CT reconstruction and FE modelling are in very good agreement, so that the concentration distributions by water sorption of PA6 calculated by FEM can be regarded as validated.
聚酰胺6（PA6）能够从周围空气中吸收水分，并通过其分子链的碳酰胺基团之间形成氢键与之结合。在吸附过程中，扩散过程会导致（部件）横截面内局部水分浓度不同，由于水诱导的增塑效应，从而导致局部机械性能不同。然而，PA6的含水量通常被指定为一个积分值，因此没有提供关于部件内局部水分分布的信息。本文展示了一种使用低能计算机断层扫描（CT）技术来表征PA6样品内水分分布的方法，并将重建结果与基于菲克扩散定律且扩散系数与浓度相关的已开发有限元（FE）建模方法进行比较。为此，考虑了样品在两种不同水浴温度以及不同积分含水量下的老化情况。CT重建和FE建模获得的结果非常吻合，因此有限元法计算得到的PA6吸水浓度分布可被视为有效。
