Structure-Thermal Conductivity Tentative Correlation for Hybrid Aerogels Based on Nanofibrillated Cellulose-Mesoporous Silica Nanocomposite

• 作者: Abdelkader Bendahou Bastien Seantier Benedicte Lebeau Dounia Bendahou Hamid Kaddami Yves Grohens
• 来源期刊: 可再生材料杂志(英文)
• 学科: 工学
• 关键词: AEROGELS cellulose MICROFIBERS WP TEMPO-oxidized NFC silica LYOPHILIZATION porosity superinsulation mechanical properties
• 年，卷（期）: 2018,（3）
• 页码范围: 299-313
• 页数: 15页
• 分类号: TB3

摘要

Hybrid aerogels have been prepared by freeze-drying technique after mixing water dispersions of cellulose microfibers or cellulose nanofibers and silica(SiO2)of type SBA-15(2D-hexagonal).The prepared composites were characterized by different analysis techniques such as SEM,hot-filament,DMA,etc.These composites are compared to those previously prepared using nanozeolites(NZs)as mineral charge.The morphology studied by SEM indicated that both systems have different structures,i.e.,individual fibers for cellulose microfibers WP-based aerogels and films for nanofibrillated cellulose NFC-based ones....These differences seem to be driven by the charge of the particles,their aspect ratio and concentrations.These hybrid materials exhibit tunable thermal conductivity and mechanical properties.The thermal conductivity values range between~18 to 28 mW.m^-1.K^-1 and confirm the superinsulation ability of these fibrous aerogels.Synergism on the thermal insulation properties and mechanical properties was shown by adjunction of mineral particles to both cellulose-based aerogels by reaching pore size lower than 100 nm.It significantly reduces the thermal conductivity of the hybrid aerogels as predicted by Knudsen et al.Furthermore,the addition of mineral fillers to aerogels based on cellulose microfibers induced a significant increase in stiffness.