Strong, Low-Density Nanocomposites by Chemical Vapor Deposition and Polymerization of Cyanoacrylates on Aminated Silica Aerogels

Abstract

Strong polymer-silica aerogel composites were prepared by chemical vapor deposition of cyanoacrylate monomers onto amine-modified aerogels. Amine-modified silica aerogels were prepared by copolymerizing small amounts of (aminopropyl)triethoxysilane with tetraethoxysilane. After silation of the aminated gels with hexamethyldisilazane, they were dried as aerogels using supercritical carbon dioxide processing. The resulting aerogels had only the amine groups as initiators for the cyanoacrylate polymerizations, resulting in cyanoacrylate macromolecules that were higher in molecular weight than those observed with unmodified silica and that were covalently attached to the silica surface. Starting with aminated silica aerogels that were 0.075 g/cm(3) density, composite aerogels were made with densities up to 0.220 g/cm(3) and up to 31 times stronger (flexural strength) than the precursor aerogel and about 2.3 times stronger than an unmodified silica aerogel of the same density.

Fluorescent hybrid organic–inorganic particles: influence of physical encapsulation versus covalent attachment on leaching and UV stability

“…It has been reported that monomers with a single trialkoxysilyl group segregate to the surface of particles during polymerizations 46), 47) and bridged monomers with two trialkoxysilyl groups are more homogeneously distributed. 48) Dansyl amides experience a substantial bathochromic shift in fluorescence emission maximum with increasing solvent polarity making them useful in probing materials' microenvironments.…”

Mechanically robust aerogels derived from an amine-bridged silsesquioxane precursor

“…To improve the mechanical properties of silica aerogels, unremitting efforts have been made [16,[19][20][21][22][23][24][25][26][27][28]. Crosslinking the silica skeleton with organic groups has been widely accepted as an effective approach of reinforcement [16,25,28].…”

A kinetics study on thein situreversible addition–fragmentation chain transfer and free radical polymerization of styrene in presence of silica aerogel nanoporous particles

“…[12][13] Many kinds of silica nanoparticles have been used to synthesize polymer nanocomposites via different polymerization systems. [14] Although some research works have been done on the properties of aerogel/polymer nanocomposites, [15][16][17] there is no study on the effect of aerogel particles on the kinetics of polymerization and physical properties of nanocomposites. In this work, free radical and RAFT polymerizations of styrene, including different amounts of nanoporous particles (silica aerogel), were investigated.…”