Abstract The tensile mechanical properties of carbon nanotube (CNT) fiber, which is a one-dimensional assembly of ultra-strong CNTs, are still far short of our expectations. This is mainly due to their high porosity and relatively weak intertube load transfer efficiency. Previous studies have demonstrated that the fiber strength can be enhanced by the infiltration of polymer chains into the fiber. In this work, polyvinyl alcohol (PVA) was pre-infiltrated into loosely packed CNT ribbons, and the composite ribbons were then densified into the fiber form. This enabled a homogeneous dispersion of polymer chains within the CNT fibers. To enhance the mechanical properties of the CNT/PVA composite fibers, isothermal crystallization and ultrasonic treatments were implemented to increase the crystallization of PVA in the ribbon, and the composite fibers were hot-stretched to improve the alignment of both CNTs and PVA chains within the fibers. It was found that the tensile strength and modulus of the final composite fiber were 210% and 193.6% higher than those of the pristine CNT fiber. The structural evolution during these treatments and the mechanism of fiber strengthening were systematically investigated.

中文翻译：

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用半结晶聚乙烯醇和热拉伸增强碳纳米管纤维

摘要 碳纳米管（CNT）纤维是一种超强碳纳米管的一维组装体，其拉伸力学性能仍远未达到我们的预期。这主要是由于它们的高孔隙率和相对较弱的管间负载转移效率。先前的研究表明，可以通过聚合物链渗透到纤维中来增强纤维强度。在这项工作中，聚乙烯醇 (PVA) 被预渗透到松散堆积的 CNT 带中，然后将复合带致密化为纤维形式。这使得聚合物链能够在 CNT 纤维内均匀分散。为了提高 CNT/PVA 复合纤维的机械性能，实施等温结晶和超声处理以增加带中 PVA 的结晶，并对复合纤维进行热拉伸以改善纤维内碳纳米管和 PVA 链的排列。结果表明，最终复合纤维的拉伸强度和模量比原始 CNT 纤维高 210% 和 193.6%。系统地研究了这些处理过程中的结构演变和纤维增强机制。