382
deposition of metals (Ag, Pd) by reducing metal ions from solution (Fry and
Nadkarni 1994; Reed-Mundell et al. 1995). Ketelson et al. (1995a; 1996a, b, 1998)
and Brook et al. (1997) also modified a Stöber colloidal silica with HMe 2 Si(OEt) or
HSi(OEt) 3 (TES) in THF or acetone, thus introducing reactive T
H
or M
H
groups on
the silica surface. The Si-H groups on the silica surface (SiO 2 -TES) were stable
within few years. The silica-supported Pt NPs (2–3.5 nm in size) were prepared by
adding the catalyst Pt 2 [(ViSiMe 2 ) 2 O] 3 to SiO 2 -TES or alumina-TES, dispersed into
THF. The supported Pt NPs were catalically active in hydrosilylation reactions
(Ketelson et al. 1995a, 1996a, b, c, 1998; Brook et al. 1997).
The radical polymerization of MMA gave poly(methyl methacrylate) grafted
onto silica surface, which was functionalized by the reaction of colloidal silica sols
with H 2 C=HSi(OMe) 3 or H 2 C=CMeCO 2 (CH 2 ) 3 Si(OMe) 3 . The vinyl functionalized
silica was reacted with HSiMe 2 -end silicones by the Pt-catalyzed hydrosilylation.
These particles were sterically stabilized in hexane (Ketelson et al. 1995b).
The synthesis of an ordered mesoporous silica with functional Si-H groups was
achieved by hydrolytic condensation of TEOS and TES in the presence of a nonionic surfactant under acidic conditions. A very high content of Si-H groups was
obtained (2.4 meq/g). The new functional micelle-templated silicates can be used
for the preparation of mesoporous hybrid silica/metal nanocomposites (Mehdi and
Mutin 2006). The silica gel functionalized with –CH 2 CH 2 SiMe 2 OSiMe 2 H groups
was further modified with dendritic and comb PMVS, which led to the formation
the branched vinyl-functionalized silica/polysiloxane hybrids useful for the immobilization of Pt and Rh catalysts, which were applied for the hydrosilylation reactions of end olefins (Rózga-Wijas et al. 2003; Michalska et al. 2004).
14.6.9 Modification of Surface Properties of Other Inorganic
Supports and Fillers
Thin layers of a crosslinked PMHS were grafted onto the silica and silicon surfaces
by the sol-gel method. The degree of crosslinking and elasticity of thin nano- and
micro-coatings with hydrofobic properties was controlled by changing molar ratio
of monomers: MDES and TES (D
H
:T
H
from 50:50 to 95:5) (Thami et al. 2007). The
high reactivity of the Si-H bond allows the application of its reactions with hydroxyl
groups of fillers for surface modification through a physical absorption on the surface of γ-Al 2 O 3 , followed by the chemisorption process (Cosgrove et al. 1990;
Tertykh et al. 2003). PMHS have also been used for hydrophobic modification of
the surface properties of inorganic supports and fillers, e.g. alumina (Tertykh et al.
2003), silica or other metal oxides (Cosgrove et al. 1990), metal hydroxides:
Al(OH) 3 , Mg(OH) 2 (Laine and Babonneau 1993), CaCO 3 , gypsum, glass and inorganic phosphate, which can be ingredients of extiguishing powder (Thomas 2001).
In line with this, PMHS-modified Mg(OH) 2 showed a good dispersibility into polyolefins (Cosgrove et al. 1990; Reihs et al. 1995).
J. J. Chruściel
deposition of metals (Ag, Pd) by reducing metal ions from solution (Fry and
Nadkarni 1994; Reed-Mundell et al. 1995). Ketelson et al. (1995a; 1996a, b, 1998)
and Brook et al. (1997) also modified a Stöber colloidal silica with HMe 2 Si(OEt) or
HSi(OEt) 3 (TES) in THF or acetone, thus introducing reactive T
H
or M
H
groups on
the silica surface. The Si-H groups on the silica surface (SiO 2 -TES) were stable
within few years. The silica-supported Pt NPs (2–3.5 nm in size) were prepared by
adding the catalyst Pt 2 [(ViSiMe 2 ) 2 O] 3 to SiO 2 -TES or alumina-TES, dispersed into
THF. The supported Pt NPs were catalically active in hydrosilylation reactions
(Ketelson et al. 1995a, 1996a, b, c, 1998; Brook et al. 1997).
The radical polymerization of MMA gave poly(methyl methacrylate) grafted
onto silica surface, which was functionalized by the reaction of colloidal silica sols
with H 2 C=HSi(OMe) 3 or H 2 C=CMeCO 2 (CH 2 ) 3 Si(OMe) 3 . The vinyl functionalized
silica was reacted with HSiMe 2 -end silicones by the Pt-catalyzed hydrosilylation.
These particles were sterically stabilized in hexane (Ketelson et al. 1995b).
The synthesis of an ordered mesoporous silica with functional Si-H groups was
achieved by hydrolytic condensation of TEOS and TES in the presence of a nonionic surfactant under acidic conditions. A very high content of Si-H groups was
obtained (2.4 meq/g). The new functional micelle-templated silicates can be used
for the preparation of mesoporous hybrid silica/metal nanocomposites (Mehdi and
Mutin 2006). The silica gel functionalized with –CH 2 CH 2 SiMe 2 OSiMe 2 H groups
was further modified with dendritic and comb PMVS, which led to the formation
the branched vinyl-functionalized silica/polysiloxane hybrids useful for the immobilization of Pt and Rh catalysts, which were applied for the hydrosilylation reactions of end olefins (Rózga-Wijas et al. 2003; Michalska et al. 2004).
14.6.9 Modification of Surface Properties of Other Inorganic
Supports and Fillers
Thin layers of a crosslinked PMHS were grafted onto the silica and silicon surfaces
by the sol-gel method. The degree of crosslinking and elasticity of thin nano- and
micro-coatings with hydrofobic properties was controlled by changing molar ratio
of monomers: MDES and TES (D
H
:T
H
from 50:50 to 95:5) (Thami et al. 2007). The
high reactivity of the Si-H bond allows the application of its reactions with hydroxyl
groups of fillers for surface modification through a physical absorption on the surface of γ-Al 2 O 3 , followed by the chemisorption process (Cosgrove et al. 1990;
Tertykh et al. 2003). PMHS have also been used for hydrophobic modification of
the surface properties of inorganic supports and fillers, e.g. alumina (Tertykh et al.
2003), silica or other metal oxides (Cosgrove et al. 1990), metal hydroxides:
Al(OH) 3 , Mg(OH) 2 (Laine and Babonneau 1993), CaCO 3 , gypsum, glass and inorganic phosphate, which can be ingredients of extiguishing powder (Thomas 2001).
In line with this, PMHS-modified Mg(OH) 2 showed a good dispersibility into polyolefins (Cosgrove et al. 1990; Reihs et al. 1995).
J. J. Chruściel