Gubała Dajana, Slastanova Anna, Matthews Lauren, Islas Luisa, Wąsik Patryk, Cacho-Nerin Fernando, Ferreira Sanchez Dario, Robles Eric, Chen Meng, Briscoe Wuge H
School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K.
Bristol Centre for Functional Nanomaterials, HH Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, U.K.
ACS Nano. 2024 Feb 9;18(7):5940-50. doi: 10.1021/acsnano.4c00114.
Erucamide is known to play a critical role in modifying polymer fiber surface chemistry and morphology. However, its effects on fiber crystallinity and mechanical properties remain to be understood. Here, synchrotron nanofocused X-ray Diffraction (nXRD) revealed a bimodal orientation of the constituent polymer chains aligned along the fiber axis and cross-section, respectively. Erucamide promoted crystallinity in the fiber, leading to larger and more numerous lamellae crystallites. The nXRD nanostructual characterization is complemented by single-fiber uniaxial tensile tests, which showed that erucamide significantly affected fiber mechanical properties, decreasing fiber tensile strength and stiffness but enhancing fiber toughness, fracture strain, and ductility. To correlate these single-fiber nXRD and mechanical test results, we propose that erucamide mediated slip at the interfaces between crystallites and amorphous domains during stress-induced single-fiber crystallization, also decreasing the stress arising from the shear displacement of microfibrils and deformation of the macromolecular network. Linking the single-fiber crystal structure with the single-fiber mechanical properties, these findings provide the direct evidence on a single-fiber level for the role of erucamide in enhancing fiber "softness".
已知芥酸酰胺在改变聚合物纤维表面化学性质和形态方面发挥着关键作用。然而,其对纤维结晶度和机械性能的影响仍有待了解。在此,同步加速器纳米聚焦X射线衍射(nXRD)揭示了组成聚合物链分别沿纤维轴和横截面排列的双峰取向。芥酸酰胺促进了纤维中的结晶度,导致更大且数量更多的片晶微晶。nXRD纳米结构表征由单纤维单轴拉伸试验补充,该试验表明芥酸酰胺显著影响纤维机械性能,降低纤维拉伸强度和刚度,但提高纤维韧性、断裂应变和延展性。为了关联这些单纤维nXRD和机械测试结果,我们提出芥酸酰胺在应力诱导的单纤维结晶过程中介导微晶与非晶域之间界面处的滑移,还降低了由微纤丝的剪切位移和大分子网络变形产生的应力。将单纤维晶体结构与单纤维机械性能联系起来,这些发现为芥酸酰胺在增强纤维“柔软度”方面的作用提供了单纤维水平的直接证据。