Personnel operating in extreme environments require equipment that protects against multiple hazards. Currently, protection against both thermal and ballistic threats requires the combination of multiple high-performance materials that increases equipment weight and complexity. Here, we hypothesized we could achieve simultaneous protection by manufacturing a porous network of aligned fibers, combining the mechanical properties of continuous fibers with the thermal properties of porous aerogels. Choosing para-aramid polymers as the building block, we engineered precursor solutions to be fluid-like during fiber spinning and solid-like during fiber formation. This allowed for the fabrication of porous, continuous para-aramid fiber sheets (pAFS) with fiber diameters an order of magnitude lower than that of commercial para-aramid fibers. Although exhibiting moderately reduced single-fiber mechanics, these pAFS had fragment projectile resistance comparable with commercial para-aramids, while providing 20-fols heat-insulation capability. With these synergistic properties, the nanofiber sheets act as a multifunctional material that can provide improved simultaneous protection.

在极端环境中工作的人员需要能够防止多种危险的设备。当前，要抵御热量和弹道威胁，就需要多种高性能材料的组合，这会增加设备的重量和复杂性。在这里，我们假设可以通过制造连续纤维的多孔网络，将连续纤维的机械性能与多孔气凝胶的热性能相结合来实现同时保护。选择对位芳族聚酰胺聚合物作为构建基块，我们将前体溶液设计为在纤维纺丝过程中呈流体状，在纤维形成过程中呈固体状。这样就可以制造多孔，连续的对位芳纶纤维片材（p纤维直径比商业对位芳族聚酰胺纤维低一个数量级。尽管这些p AFS表现出适度降低的单纤维力学性能，但其碎片抗性与商业对位芳族聚酰胺相当，同时提供20箔的绝热能力。具有这些协同性能，纳米纤维片材充当多功能材料，可以提供改进的同时保护。