For the first time, we map the conditions that lead to the successful preparation of carbon nanofibers from a blend of lignin and recycled poly(ethylene terephthalate) (r-PET). Particularly, we describe how their morphology depends on the synergy between the lignin/r-PET mass ratio and the average fiber diameter of the precursor fibers. Electrospun mats consisting of different lignin/r-PET mass ratios (from 50/50 to 90/10) and different average fiber diameters (from 80 to 400 nm) were prepared. After carbonizing them to 600 °C, it was repeatedly observed that the samples having a relatively high mass ratio of r-PET (> 33 wt%) and low average fiber diameters (~ 100 nm) exhibit extensive melting and the fibrous structure collapses. In contrast, samples of the same high mass ratio of r-PET but large average fiber diameters (> 300–400 nm) yield infusible filamentous carbon structures. This nano-dimension phenomenon declines when the r-PET content is low enough (~ 10 wt%). In this case, the nanofibers are practically infusible and carbon nanofibers with average diameters close to 100 nm and a well-formed filamentous structure are produced. Such thin lignin-based carbon nanofibers have scarcely been reported. The reasons leading to the melting of the nanofibrous mats which consist of certain mass ratios and average fiber diameters are related to variations in the decomposition rates of the two precursor polymers and also to differences in their crystallization. These phenomena are explained based on experimental results from thermogravimetry, X-ray diffraction and differential scanning calorimetry. Moreover, BET surface area measurements indicate that the melting of nanofibrous mats compromises the porosity of the activated carbon nanofibers produced from them, while the presence of r-PET has a positive impact on the development of porosity.

中文翻译：

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由木质素/ r-PET共混物制备碳纳米纤维：质量比与平均纤维直径的协同作用

首次，我们绘制了从木质素和再生聚对苯二甲酸乙二醇酯（r-PET）的混合物成功制备碳纳米纤维的条件。特别是，我们描述了它们的形态如何取决于木质素/ r-PET质量比与前体纤维的平均纤维直径之间的协同作用。制备了由不同的木质素/ r-PET质量比（从50/50到90/10）和不同的平均纤维直径（从80到400 nm）组成的电纺垫。将它们碳化至600°C后，反复观察到具有较高r-PET质量比（> 33 wt％）和低平均纤维直径（〜100 nm）的样品表现出广泛的熔融性，并且纤维结构塌陷。相比之下，r-PET的质量比相同但平均纤维直径较大的样品（> 300–400 nm）产生不溶的丝状碳结构。当r-PET含量足够低（〜10 wt％）时，这种纳米尺寸现象会降低。在这种情况下，纳米纤维实际上是不熔的，并且生产出平均直径接近100nm并且形成良好的丝状结构的碳纳米纤维。几乎没有报道过这种基于木质素的薄碳纳米纤维。导致由某些质量比和平均纤维直径组成的纳米纤维垫熔化的原因与两种前体聚合物的分解速率变化以及它们的结晶差异有关。根据热重分析，X射线衍射和差示扫描量热法的实验结果解释了这些现象。此外，