Advancements in processing techniques have facilitated the development of a series of unique high-performance DuPont™ Kevlar^® fibers. Directly characterizing interior structures of these fibers is vital for connecting processing variations with resulting mechanical properties. Here we report detailed investigations of processing-internal structure-property relationships among four distinct classes of Kevlar^® fibers (K119, K29, KM2+, and K49). We employ a novel focused ion beam (FIB) notch technique to obtain pristine interior fiber planes and measure morphology and transverse stiffness across these surfaces via multifrequency atomic force microscopy (AFM) maps. Combining these observations with tensile tests of single fibers drawn from the same tows, we acquire remarkable insights into structural motifs that strongly correlate with measured mechanical properties. Most notably, we uncover alternating stiffness bands that are especially apparent in low-modulus, non-heat-treated fibers, revealing a unique manifestation of internal structural variations that helps explain the observed trends in material response.

在加工技术的进步促进了一系列独一无二的高性能杜邦™凯芙拉的发展^®纤维。直接表征这些纤维的内部结构对于将加工变化与产生的机械性能联系起来至关重要。在这里，我们报告中详述的中四种不同种类的Kevlar处理，内部结构-性能关系的调查^®纤维（K119，K29，KM2 +，和K49）。我们采用了新颖的聚焦离子束（FIB）切口技术以获得在这些表面的原始内部纤维平面和测量形貌和横向刚度经由多频原子力显微镜（AFM）图。将这些观察结果与从同一根丝束引出的单根纤维的拉伸测试相结合，我们获得了对与测得的机械性能密切相关的结构图案的深刻见解。最值得注意的是，我们发现在低模量，未经热处理的纤维中尤为明显的交变刚度带，揭示了内部结构变化的独特表现形式，有助于解释观察到的材料响应趋势。