Surface chemical modification of silica aerogels using various alkyl-alkoxy/chloro silanes

Rao, A. Venkateswara; Kulkarni, Mukund G.; Amalnerkar, Dinesh; Seth, Tanay

doi:10.1016/s0169-4332(02)01232-1

Cited by 146 publications

(68 citation statements)

References 24 publications

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“…[2][3][4][5][6] Another promising way to improve the mechanical properties is to make aerogels hydrophobic by post-treatment with surface modification agents or by the hybridization of silica aerogels via a cocondensation approach of silicon alkoxides with organosilane precursors that contain hydrophobic groups. [7][8][9][10][11] Recently, different flexible organic-inorganic hybrid aerogels were made solely from a methyltrimethoxysilane (MTMS) or vinyltrimethoxysilane (VTMS) precursor. Rao et al produced flexible as well as bendable, superhydrophobic and low-density gels, that were dried supercritically and had a reversible elastic compression of up to 60%.…”

Section: Introductionmentioning

confidence: 99%

Flexible organofunctional aerogels

et al. 2017

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Flexible inorganic-organic silica aerogels based on methyltrimethoxysilane (MTMS, CH 3 Si(OCH 3 ) 3 ) can overcome the drawbacks of conventional silica aerogels by introducing high mechanical strength, elastic recovery and hydrophobicity to monolithic materials. In this work, MTMS is co-condensed with organofunctional alkoxysilanes RSi(OMe) 3 (R = vinyl, chloropropyl, mercaptopropyl, methacryloxypropyl, etc.) yielding aerogels that are not only flexible but also contain reactive functional groups. Sol-gel parameters, such as the MTMS/RSi(OMe) 3 ratio, have been systematically investigated in terms of gelation behavior, complete/incomplete incorporation of the functional organic groups (confirmed by FTIR-ATR and Raman spectroscopy) and flexibility of the resulting gel. Sterically more demanding functional moieties lead to macroscopic phase separation; however, this problem was overcome by the employment of surfactants. Functional aerogels dried by supercritical extraction with carbon dioxide showed promising results in uniaxial compression tests and had an elastic recovery up to 60%. Furthermore, the accessibility of the functional groups was demonstrated by simple reactions, e.g. conversion of the chloro into azido groups via a nucleophilic substitution reaction with NaN 3 followed by click reactions.

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Section: Introductionmentioning

confidence: 99%

Flexible organofunctional aerogels

et al. 2017

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“…Conventionally, the surface treatments with various modifiers such as silanes have been used to improve the filler dispersion and strength the rubber/silica interfacial bonding [1][2][3][4]. Due to the high polarity of silica particles, the dispersion of silica in silane included systems and controllability of the performance are far from satisfactory.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of novel functional liquid and its application as a modifier in SBR/silica composites

Lei¹,

Tang²,

Guo³

et al. 2010

Express Polym. Lett.

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Abstract.A novel functional ionic liquid (IL), 1-methylimidazolium methacrylate (MimMa), was synthesized for modifying styrene butadiene rubber (SBR)/silica composites. MimMa was found to be readily polymerized via the initiated radical mechanism and could be analogously grafted onto rubber chains during vulcanization. Substantial hydrogen bonding between polymerized MimMa (poly(MimMa)) and silica can facilitate the silica dispersion and improve the SBR/silica interfacial bonding. Filler networking, curing behavior, silica dispersion and mechanical performance of the modified SBR/silica composites were studied. With a low concentration of MimMa, remarkable improvements in the interfacial interactions and mechanical properties were achieved which was attributed to the improved silica dispersion and strengthened interfacial bonding induced by MimMa. A modified interphase structure was accordingly proposed and related to the mechanical performance of the modified SBR/silica composites.

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“…Various methods of modifying the silica surface, therefore, are always of great importance in tailoring filler dispersion and interfacial interactions for rubber/filler composites. [5][6][7][8] Ionic liquid (IL), a novel emerging medium, is getting worldwide attention for its fascinating properties, such as near-zero vapor pressure, high thermal stability, high conductivity and wide potential window. 9,10 Traditionally, ILs with various inorganic anions have been extensively used as green solvents (electrolyte and dispersing agents) owing to their high thermal stability, non-flammability and non-volatility.…”

Section: Introductionmentioning

confidence: 99%

SBR/silica composites modified by a polymerizable protic ionic liquid

Lei

Tang

Guo

et al. 2010

Polym J

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A novel functionalized ionic liquid, 1-methylimidazolium sorbate (MimS), was synthesized and characterized. MimS was used to improve the performance of rubber/silica composites. Substantiated hydrogen bonding between MimS and silica was responsible for effectively restraining the Payne effect and decreasing the Mooney viscosity of the uncured rubber compounds. The reactivity of MimS toward rubber and its ability to hydrogen bond with polymerized MimS and silica were characterized. Filler networking, curing behavior, silica dispersion and mechanical performance of the vulcanizates were fully studied. Remarkable improvements in mechanical properties were achieved with only a small addition of MimS. Variations in rubber performance were attributed to the significantly improved silica dispersion and novel interfacial interactions induced by MimS.

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Surface chemical modification of silica aerogels using various alkyl-alkoxy/chloro silanes

Cited by 146 publications

References 24 publications

Flexible organofunctional aerogels

Flexible organofunctional aerogels

Synthesis of novel functional liquid and its application as a modifier in SBR/silica composites

SBR/silica composites modified by a polymerizable protic ionic liquid

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