The Hermans orientation factor is a scalar giving a simple assessment of molecular or crystal orientation in a polymer. It is usually determined from X‐ray diffraction measurements. The evaluation of the Hermans orientation factor is proposed from the diffraction analysis of only a single diffracting plane. The estimation relies on (a) the assumption that the polymer crystals possess a cylindrical symmetry with respect to the chain direction and (b) that the processing conditions induce a transverse isotropy of the polymer chains. A practical consequence of the proposed analysis is that the Hermans orientation factor can be computed from a single 1D diffractogram. This enables fast evaluations since even low signal‐to‐noise ratio signals can be processed with optimal noise reduction. An illustration of this method for uniaxially compacted polytetrafluoroethylene (PTFE) powder is presented. The crystalline orientation is followed during in situ crystallization experiments with a fine time resolution.

中文翻译：

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横观各向同性半结晶聚合物的晶体取向评估：在PTFE的测压中的应用

Hermans取向因子是一个标量，可简单评估聚合物中分子或晶体的取向。通常由X射线衍射测量确定。仅通过单个衍射平面的衍射分析提出了Hermans取向因子的评估。该估计基于以下假设：（a）聚合物晶体相对于链方向具有圆柱对称性，以及（b）加工条件引起聚合物链的横向各向同性。提出的分析的实际结果是，可以从单个一维衍射图中计算出Hermans取向因子。这可以实现快速评估，因为即使以最佳的降噪方式处理低信噪比的信号也是如此。给出了这种单轴压实聚四氟乙烯（PTFE）粉末的方法的说明。在原位结晶实验中遵循良好的时间分辨率进行结晶取向。