Trigo-López Miriam, Miguel Álvaro, García José M, Mendía Aránzazu, Ruiz Virginia, Valente Artur J M, Vallejos Saúl
Grupo de Polímeros, Departamento de Química, Facultad de Ciencias, Universidad de Burgos, Plaza de Misael Bañuelos s/n, 09001 Burgos, Spain.
Facultad de Ciencias, Universidad Autónoma de Madrid, Calle Einstein 3, 28049 Madrid, Spain.
Polymers (Basel). 2023 Nov 3;15(21):4315. doi: 10.3390/polym15214315.
Gradient porous materials, particularly carbon-based materials, hold immense potential in the fields of batteries, energy storage, electrocatalysis, and sensing, among others, by synergistically combining the attributes associated with each pore size within a unified structural framework. In this study, we developed a gradient porous aramid (GP-Aramid) by incorporating cellulose acetate as a porosity promoter in the polymer casting solution in different proportions. These GP-Aramids were subsequently transformed into their pyrolyzed counterparts (GP-Pyramids), retaining their original structures while displaying diverse cellular or dense microstructures inherited from the parent aramid, as confirmed via scanning electron microscopy. X-ray diffraction spectra provided evidence of the conversion of aramids into carbonaceous materials. The materials showed structural defects observed through the intensity ratio of the G and D bands (ID/IG = 1.05) in the Raman spectra, while X-ray photoelectron spectra (XPS) revealed that the carbonization process yielded pyrolyzed carbon materials unusually rich in nitrogen (6%), oxygen (20%), and carbon (72%), which is especially relevant for catalysis applications. The pyrolyzed materials showed bulk resistivities from 5.3 ± 0.3 to 34.2 ± 0.6 depending on the meta- or para-orientation of the aramid and the porous structure. This work contributes to understanding these gradient porous aromatic polyamides' broader significance and potential applications in various fields.
梯度多孔材料，尤其是碳基材料，通过在统一的结构框架内协同结合与每个孔径相关的属性，在电池、储能、电催化和传感等领域具有巨大潜力。在本研究中，我们通过在聚合物浇铸溶液中以不同比例加入醋酸纤维素作为孔隙率促进剂，制备了一种梯度多孔芳纶（GP-芳纶）。随后，这些GP-芳纶被转化为其热解产物（GP-热解产物），通过扫描电子显微镜证实，它们保留了原始结构，同时呈现出从母体芳纶继承而来的多样的蜂窝状或致密微观结构。X射线衍射光谱提供了芳纶转化为含碳材料的证据。通过拉曼光谱中G带和D带的强度比（ID/IG = 1.05）观察到材料存在结构缺陷，而X射线光电子能谱（XPS）显示，碳化过程产生的热解碳材料富含氮（6%）、氧（20%）和碳（72%），这对于催化应用尤为重要。根据芳纶的间位或对位取向以及多孔结构，热解材料的体电阻率在5.3±0.3至34.2±0.6之间。这项工作有助于理解这些梯度多孔芳香族聚酰胺在各个领域的更广泛意义和潜在应用。
