製備苯乙烯-丙烯腈共聚物多孔纖維氣凝膠應用於 空氣懸浮微粒過濾

Abstract

空氣中的污染物，包括懸浮微粒 (PM) 、病原體和氣體，對於人體健康帶來了嚴重的挑戰。靜電紡絲技術已成為一種製備奈米纖維的簡便方法，用於分離空氣污染物。在本研究中，透過實驗室所歸納出的成孔機制和條件，製備出具有多孔結構的電紡纖維，並結合製備氣凝膠的技術，除了纖維表面上具有孔洞結構外，將體先的2D纖維薄膜變成3D立和網狀結構可大幅提升比表面積，成功製備出由苯乙烯-丙烯腈共聚物 (SAN) 所構成的具極低密度、高孔隙度的氣凝膠。 由於氣凝膠本身機械性能不足，本研究會加入少量水溶性高分子作為“黏著劑”來黏合分散的SAN電紡纖維，其中以添加聚乙烯醇 (PVA) 的效果最佳，在不破壞纖維孔洞的情況下，不僅提升了最大抗拉強度，所含之高極性的官能基也可提升對PM2.5的吸附能力。而透過比較添加不同水解程度的PVA可發現，相比於低水解程度的PVA，於高水解程度下會產生微孔結構，進一步增加氣凝膠的比表面積，可有效提升吸附PM2.5的能力。 在過濾性能方面，所得的複合氣凝膠展現出高於99 %的高過濾效率，僅66 Pa的低壓降。此外，本研究所使用之分散液為水與酒精，相較於傳統氣凝膠的製程，不僅製備步驟更為簡單且對環境友善。透過調控製程參數可製備出具不同結構的氣凝膠，於空氣污染物過濾應用上展現出巨大潛力。

Airborne pollutants, including particulate matter (PM), pathogens, and gases, pose significant health risks. Electrospinning has emerged as an effective method for producing nanofibers that are ideal for separating air pollutants. Porous electrospun fibers with a porous structure were fabricated based on the pore-forming mechanisms and conditions established in the laboratory. By combining aerogel fabrication techniques, the original 2D fibrous membranes were transformed into 3D network structures, significantly enhancing the specific surface area, resulting in aerogels made from styrene-acrylonitrile (SAN) copolymers that feature ultralow density and high porosity. To address the aerogel's mechanical limitations, a small amount of water-soluble polymer was added as a ''glue'' to bind the dispersed SAN nanofibers. Among the tested polymers, polyvinyl alcohol (PVA) provided the best results, enhancing tensile strength without disrupting the fiber's pore structure. Furthermore, the polar functional groups in PVA contributed to improved PM2.5 adsorption. By comparing the addition of PVA with different degrees of hydrolysis, PVA with a higher degree of hydrolysis formed microporous structures that further increased the specific surface area of the aerogel compared to PVA with a low degree of hydrolysis. Additionally, the higher number of polar functional groups effectively enhanced its ability to adsorb PM2.5. The composite aerogels demonstrated excellent performance with over 99% filtration efficiency and a low-pressure drop of 66 Pa. Furthermore, using water and alcohol as dispersion made the fabrication process simpler and more environmentally friendly than traditional aerogel methods. The aerogels can be tailored for various structures, offering great potential for air pollutant filtration applications.