纳米纤维素基吸油气凝胶的制备及性能

以竹粉为原料制备纳米纤维素基体材料,以聚乙烯醇(PVA)为增强相,在酸性环境下采用冷冻干燥法制得PVA/CNFs(纳米纤维素)复合气凝胶;采用三甲基氯硅烷(TMCS)对其进行疏水改性处理,随后将其浸渍到还原氧化石墨烯(r GO)悬浮液中,最终制得疏水型r GO/PVA/CNFs复合气凝胶;通过扫描电子显微镜(SEM)、傅里叶变换红外光谱(FT-IR)、拉曼光谱(Raman)、接触角(CA)和吸油性能测试,对所制气凝胶的微观形貌、化学结构、疏水性能及吸油性能进行表征。结果表明:制得的复合气凝胶密度为6.78 mg/cm3,具有均匀的三维网状多孔结构,且孔洞结构表面均被石墨烯片层覆盖;经过TMCS疏水处理后,在气凝胶表面形成疏水层结构。FT-IR和Raman分析表明,TMCS疏水改性处理并未改变PVA/CNFs复合气凝胶的化学结构。经疏水处理后气凝胶与水的接触角为138°左右,吸油倍率为78 g/g左右,且吸附过程迅速,饱油后也能悬浮于溶液表面,便于回收再利用。

Preparation and properties of nanocellulose-based oil-absorbing aerogels

In recent years,much attention has been paid to aerogel materials research and as potential applications in many fields.Cellulose nanofiber (CNF) is a common renewable organic polymer in nature,which has excellent hydrophilicity,biocompatibility,high degree of polymerization,easy for chemical modification and formation of gel materials and membrane materials.In this study,nanocellulose matrix materials were prepared from bamboo powder.The polyvinyl alcohol (PVA) was used as the reinforcing phase and PVA/CNFs composite aerogels were prepared by freeze-drying under acidic conditions.Then the trimethylchlorosilane (TMCS) was used for the hydrophobic modification.After the modification,it was impregnated into a reduced graphene oxide (rGO) suspension.The hydrophobic rGO/PVA/CNFs composite aerogel was finally obtained.The morphological feature,internal pore structure,chemical construction,surface wettability,hydrophobic properties and oil absorption properties of the novel cellulose based composite aerogel were analyzed using the scanning electron microscopy (SEM),Fourier transform infrared spectroscopy (FT-IR),Raman spectroscopy (Raman),water contact angle (CA) and oil absorption performance tests.The results showed that the density of the composite aerogel was 6.78 mg/cm 3 .The aerogel had a uniform three-dimensional network porous structure,and the surface of the pore structure was covered by graphene sheets.After the aerogel was subjected to hydrophobic treatment by the TMCS,a hydrophobic layer structure was formed on the surface.The results of the FT-IR and Raman analysis showed that the hydrophobic modification of the TMCS did not change the chemical structure of the PVA/CNFs composite aerogel.After the aerogel was treated by hydrophobic,the water contact angle of the aerogel was about 138°,the oil absorption ratio was about 78 g/g,and the adsorption process was quick.After the oil was saturated,it could be suspended on the surface of the solution for recycling and reuse.The hydrophobic composite aerogel obtained in this study could provide a theoretical foundation for the application of CNFs-based aerogels in removing leaked oils and organic solvents.