The increasing usage of polyurea coatings has attracted the attention of researchers worldwide. Commercial polyurea formulations contain chain extenders as an essential ingredient, which increases the possibility of intermolecular H‐bonding by bringing the urea linkages closer. In this work, we establish the effect of increasing chain length of chain extender on the material properties of the polymer. Different types of chain extender were blended with a long chain diamine and subsequently reacted with an MDI‐based isocyanate prepolymer through a reactive spray processing technique. Polyurea coatings containing aromatic chain extenders were found to exhibit higher tensile strength as compared to their aliphatic analogues. Increasing the chain length of the aliphatic chain extender led to a reduction in the mechanical strength. A suitable combination of aromatic and aliphatic chain extender of short length was found to force the macromolecule to orient in such a fashion so as to result in optimal H‐bonding. This manifested in terms of improved processability, as confirmed by chemorheological investigations. Fourier transform infrared spectroscopy was used to understand the H‐bonded internal structure of the polymer. Optimum H‐bonding resulted in improved mechanical properties of the spray‐coated polyurea. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48573.

中文翻译：

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可喷涂加工的聚脲配方：扩链剂长度对聚脲涂料材料性能的影响

聚脲涂料使用的增加吸引了全世界研究人员的注意力。商业聚脲配方含有扩链剂作为必不可少的成分，通过使尿素键更紧密，增加了分子间氢键的可能性。在这项工作中，我们建立了增加扩链剂链长对聚合物材料性能的影响。将不同类型的扩链剂与长链二胺混合，然后通过反应喷涂工艺与基于MDI的异氰酸酯预聚物反应。与它们的脂族类似物相比，发现含有芳族扩链剂的聚脲涂料表现出更高的拉伸强度。脂族扩链剂的链长增加导致机械强度降低。发现合适的短长度芳族和脂肪族扩链剂组合可以迫使大分子以这种方式定向，从而导致最佳的H键合。如化学流变学研究所证实的，这表现为改善的可加工性。傅里叶变换红外光谱用于了解聚合物的氢键内部结构。最佳的H键合可以改善喷涂聚脲的机械性能。分级为4 +©2019 Wiley Periodicals，Inc.J.Appl。Polym。科学 傅里叶变换红外光谱用于了解聚合物的氢键内部结构。最佳的H键合可以改善喷涂聚脲的机械性能。分级为4 +©2019 Wiley Periodicals，Inc.J.Appl。Polym。科学 傅里叶变换红外光谱用于了解聚合物的氢键内部结构。最佳的H键合可以改善喷涂聚脲的机械性能。分级为4 +©2019 Wiley Periodicals，Inc.J.Appl。Polym。科学2020，137，48573。