Synthesis of Hybrid Organic−Inorganic Materials from Interpenetrating Polymer Network Chemistry

Abstract

Organic−inorganic interpenetrating polymer networks were synthesized with an SiO2 phase made by sol−gel chemistry and the organic phase made from poly(2-hydroxyethyl acrylate). The resultant morphologies were characterized by small-angle scattering and electron microscopy. When the vinyl polymerization is more rapid than the sol−gel reaction, gross phase separation occurs giving a heterogeneous structure. For comparable rates of the two polymerizations, the specimens have a dendritic morphology on the scale of 0.5 μm. The more rapid formation of the silica phase relative to the organic network produces rigid and optically transparent materials, with a finely divided structure as seen by transmission electron microscopy. The glass content of these materials is about 0.15 g/g and the sizes of the SiO2-rich domains are 100 Å or less. Addition of tetrakis(2-(acryloxy)ethoxy)silane was also studied and found to promote phase mixing between the organic and inorganic phases.

The influence of addition of a catalyst and chelating agent on the properties of titanium dioxide synthesized via the sol–gel method

“…The sol-gel process is a useful synthetic method for the preparation of amorphous, as well as structurally ordered, materials. It offers advantages such as the possibility of obtaining homogeneous hybrid materials at low temperature, thereby enabling the incorporation of a variety of compounds [28][29][30][31][32][33][34]. A typical sol-gel method is based on hydrolysis and condensation of the precursor (inorganic metal salts or metal organic compounds such as metal alkoxides) [24].…”

P(EMA-co-HEA)/SiO2 hybrid nanocomposites for guided dentin tissue regeneration: structure, characterization and bioactivity.

“…On the contrary, Jackson et al [113] observed phase separation when the free radical polymerization of the acrylate groups was fast with respect to the sol-gel reaction. Rodríguez et al [149] also observed a highly efficient filling of the silica pores by the organic polymer matrix' chains in PHEA/SiO 2 nanocomposites obtained by a similar procedure, and related it with the silica polymerization occurring faster than the organic polymerization.…”

“…Polymers that have been hybridized with this purpose include poly(ε-caprolactone) [103][104][105][106] , poly(2-hydroxyethyl methacrylate) [89][90][91][107][108][109][110][111][112] , poly(2-hydroxyethyl acrylate) [113] , poly(methyl methacrylate) [92,114] , poly(butyl acrylate) [115] , poly(ethylene oxide) [116,117] , poly(ethylene oxide-co-epichlorhydrin) [118] , polyimide [119] , polyamide 6,6 [120] , poly(vinyl acetate) [121] , or poly(vinyl alcohol) [122] .…”

“…Acrylates have been proposed in the literature for biomedical applications because of their good biocompatibility and water permeation characteristics [136][137][138] . A 70/30 wt% hydrophobic/hydrophilic copolymer of poly(ethyl methacrylate-co-hydroxyethyl acrylate), P(EMA-co-HEA), has been chosen according to two requirements: good mechanical properties provided by the EMA component and hydrophilicity of the HEA needed for a good miscibility of the TEOS mixture [113] , for the transport of oxygen and nutrients and for cells metabolism. P(EMA-co-HEA)/SiO 2 nanocomposites with different silica contents in the range of 0-30 wt% will be obtained.…”

“…As stated previously, under these conditions the condensation rate is much greater than the production of silanols by the hydrolysis reaction, and the silica forms as a weakly crosslinked or ramified silicate network [70,91,124,129,159] . The hydrolysis of acrylate esters at acid pH is quite slow [113] . The water/TEOS molar ratio employed was below the stoichiometry of the hydrolysis reaction (2 instead of 4), which hinders the shrinkage due to the sol-gel polymerization of TEOS [91] .…”