title: Heat insulation performance, mechanics and hydrophobic modification of cellulose-SiO2 composite aerogels.
abstract: Cellulose-SiO2 composite hydrogel was prepared by combining the NaOH/thiourea/H2O solvent system and the immersion method with controlling the hydrolysis-fasculation rate of tetraethyl orthosilicate (TEOS). The hydrophobic composite aerogels were obtained through the freeze-drying technology and the cold plasma modification technology. Composite SiO2 could obviously reduce the thermal conductivity of cellulose aerogel. The thermal conductivity could be as low as 0.026 W/(mK). The thermal insulation mechanism of the aerogel material was discussed. Composite SiO2 reduced hydrophilicity of cellulose aerogel, but environmental humidity had a significant influence on heat insulation performance. After hydrophobic modification using CCl4 as plasma was conducted, the surface of composite aerogel was changed from hydrophilic to hydrophobic and water contact angle was as high as 132°. The modified composite aerogel still kept good heat insulation performance. This work provided a foundation for the possibility of applying cellulose-SiO2 composite aerogel in the insulating material field.
authors.affiliation: Key Lab of Advanced Materials of Tropical Island Resources, Ministry of Education, College of Materials and Chemical Engineering, Hainan University, Haikou 570228, Hainan, China.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Shi
authors.forename: Lingbin
authors.initials: L
authors.lastname: Lu
authors.forename: Wantao
authors.initials: W
authors.lastname: Guo
authors.forename: Jingying
authors.initials: J
authors.lastname: Zhang
authors.forename: Yang
authors.initials: Y
authors.lastname: Cao
mesh_terms: D002482:Cellulose / Q000737:chemistry*; D005782:Gels; D006868:Hydrolysis; D057927:Hydrophobic and Hydrophilic Interactions; D007101:Immersion; D055595:Mechanical Phenomena; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D012972:Sodium Hydroxide / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013814:Thermal Conductivity; D013890:Thiourea / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D005782:Gels; D012821:Silanes; D012997:Solvents; D014867:Water; C040733:tetraethoxysilane; D012972:Sodium Hydroxide; D012822:Silicon Dioxide; D002482:Cellulose; D013890:Thiourea
keywords: Cellulose aerogel; Cold plasma modification; Composite aerogel; Heat insulation performance; SiO(2)