Pickering乳液凝胶法构筑高疏水型纤维素纳米纤/聚乳酸复合气凝胶

Highly Hydrophobic Cellulose Nanofiber/Polylactic Acid Composite Aerogels by Pickering Emulsion Strategy

近年来,随着油品污染问题的日益严重,油水分离越来越受到人们的关注。首先利用纤维素纳米纤(CNF)稳定的Pickering乳液技术制备了CNF/聚乳酸(PLA)复合气凝胶,在此基础上使用聚甲基氢硅氧烷(PMHS)对其进行疏水改性,得到了具有高疏水性的复合气凝胶(HCPCA),并探究了聚甲基氢硅氧烷改性CNF/PLA气凝胶的疏水机理。研究表明,所得的HCPCA气凝胶不仅保持了原有的多孔结构,还具有良好的疏水性,水接触角随PMHS用量的增加而增大,其中HCPCA-3的水接触角达到141.0°。同时,该复合气凝胶还具有优异的油水选择性,对各种油类和化学溶剂的吸附能力最高可达到自身质量的132倍,同时可快速高效地分离油水混合溶液。所得的高疏水性的气凝胶材料在油水分离和环境保护领域具有潜在的应用前景。

With the worsening of the oil-product pollution problem,oil-water separation has attracted more and more attention in recent years.In this study,a highly hydrophobic cellulose nanofiber(CNF)/polylactic acid(PLA)aerogel as effective oil absorbent was fabricated from Pickering emulsion gel stabilized by CNF with PLA/1,2-dichloroethane droplets,followed by simple chemical graft of polymethylhydrosiloxane(PMHS)onto the surface of the CNF/PLA composite aerogel.It is worth mentioning that in this study,polymers were directly used as silane modifier and further explored the hydrophobic mechanism of PMHS modified CNF/PLA aerogels.The resulting hydrophobic CNF/PLA composite aerogels(HCPCA)still keep their original porous structure and have excellent hydrophobicity.Their water contact angle is increased with the increased dosage of PMHS,and the water contact angle of the HCPCA-3 reaches up to 141.0°.In the meantime,the composite aerogel has excellent oil/water selectivity and relatively high absorption capacity(132 times its own mass)to various oils and chemical solvents.These studies demonstrate that the material is viable candidate for use in oil-water separation and environmental protection.