Elastic silica aerogel using methyltrimethoxysilane precusor via ambient pressure drying

Abstract

The use of N,N-dimethylformamide (DMF) as a drying control chemical additive was found to be effective in obtaining methyltrimethoxysilane (MTMS) based silica aerogels in terms of excellent monolithic property, hydrophobicity and elasticity. The aerogels were produced by hydrolysis and condensation of methanol diluted MTMS in presence of ammonia catalyst followed by ambient drying. The molar ratio of DMF/MTMS varies from 0 to 1. It has been observed that higher DMF/MTMS value leads to lower density (*0.15 g/cm 3 ) and higher porosity of aerogels with excellent hydrophobicity. For DMF/MTMS (*0.6) values, monolithic and elastic aerogels which can recover to their original shapes after compression were obtained. Narrower and more uniform pore size distribution was observed for the DMF modified aerogels in our study.

Robust Silica-Bacterial Cellulose Composite Aerogel Fibers for Thermal Insulation Textile

“…Researchers worldwide have mainly focused on improving the mechanical properties of aerogel materials through precursor regulation and external doping. Methods of regulating gel precursors include increasing the quantity of precursors [ 10 ], using precursors containing inert groups [ 11 , 12 , 13 ], using precursors with flexible chains [ 14 , 15 , 16 ], and using precursors containing polymer monomers to construct bimolecular chain cross-linking network structures [ 17 , 18 ] to reduce the content of rigid –Si–O–Si–, giving the gel skeleton excellent flexibility to resist the impact of external forces. The external doping strategy includes a mixed extrusion of aerogel powder and long fiber [ 19 ], dispersion fiber doping [ 20 ], reinforcement by fiber felt [ 21 , 22 ] and isometric growth of polymers on the aerogel skeleton [ 23 , 24 ] to connect different areas of the skeleton or expend the connection area of the nanoparticles.…”

High Nanopore Volume Tetrethoxysilane Based Aerogels Prepared with Addition of N, N-Dimethylformamide at Different Stage of the Sol-Gel Process

“…He et al synthesized the water-glass-based silica aerogel with uniform pore structure, and its pore volume was as high as 3.3 cm 3 /g after the addition of dimethylformamide (DMF) [18]. Similarly, Cai et al prepared methyltrimethoxysilane based silica aerogels that exhibit uniform pore structures [20]. Using tetraethoxysilane (TEOS) as a precursor, Vollet et al researched the structure of aerogels prepared by sonohydrolysis method with additions of DMF [21].…”

Lightweight foams of amine-rich organosilica and cellulose nanofibrils by foaming and controlled condensation of aminosilane

“…as thermal and acoustic insulation materials, 2 CO 2 3 and oil sorbents, and water purification filters. 4 Organosilica foams can be produced in several ways, including sol-gel processing of an organofunctional silane (OS), [5][6][7] co-gelation of an OS with tetra-alkoxysilanes 8,9 or post-modification of silica alcogels. 10 The sol-gel processing of the OS is done in a multistep (i to iv) process involving the use of an alcohol-water mixed solvent.…”

“…21 Other processing techniques have thus been investigated, which include the use of solvents with reduced surface tension (e.g. isopropanol/n-hexane, 13 N,N-dimethylformamide 6 and ethanol/heptane 25 ), in situ polymerization in organosilica gel 8,26,27 or direct polymer addition 28,29 to an OS solution. 2 In situ polymerization in wet silica gels can lead to the formation of a strongly cross-linked polymer/silica network, resulting in a monolithic aerogel with limited shrinkage (16%).…”