Hybrid materials poly -silica

By using a similar procedure for the preparation of hybrids of silica, hybrids materials consisting of other metal oxides were also prepared by the group of Wilkes [15]. For example, titania was incorporated into organic polymers by using the chemically controlled condensation (CCC) method for the preparation of poly(tetramethylene oxide)-silica or poly(dimethylsiloxane)-silica hybrids. Especially, in the case of the hybrid with poly (tetramethylene oxide), the modulus or ultimate strength of the hybrid increased in the presence of titania component, as shown in Table 3. This phenomenon was explained by the catalytic ability of... 

Noell et al. reported the preparation of silica-poly(ether ether ketone) hybrid materials with improved physical properties.155 An amine-end-capped poly(ether ether ketone) was used to react with isocyanatopropyltriethoxysilane in tetrahydrofuran (THF). The triethylsilane-end-capped poly (ether ether ketone) was mixed with tetraethoxysilane (TEOS) in THF. Quantitative amounts of water were introduced into die system, and the mixture was reduxed at 80°C. The entire reaction mixture was allowed to further react in Tedon molds. Tough transparent materials were obtained by diis approach. 

Although the biocompatibility and biodegradability of these materials were rapidly determined, the bioactivity of Si02-PCL hybrid materials was not studied until recently [99]. In order to provide bioactivity to Si02-PCL hybrid materials, Rhee prepared triethoxysilane end-capped poly(s-caprolactone) which was then cocondensed with tetraethyl orthosilicate and calcium nitrate via the sol-gel method. The Ca-containing PCL/silica hybrid so obtained showed in vitro bioactivity and biodegradability. The hybridization procedure between the a,co-hydroxyl PCL and silica phases was proposed to be as follows ... 

Organic-silica hybrid materials have been used for multi-photon microfabrication. These include the acrylate-functionalized oligosiloxanes known as ORMOCERs, which have been polymerized by radical processes using conventional IP radical iniatitors, such as c.2 [221,234]. Commercial poly(dimethylsiloxane)-based resists containing vinyl and Si-H functionalities use two different 2PA-induced processes hydrosilylation catalyzed by the photodecomposition products of Cp PtMes (Cp = ti -methylcyclopentadienyl) and radical initiation by c.4 (Fig. 13) [235]. The former process was complicated by thermally-induced polymerization. 

The chemical entrapment of TEMPO moiety in the sol-gel silica hybrid material is performed in two steps reductive amination of 4-oxo-TEMPO with 3-aminopropyl-trimethoxysilane (APTMS) followed by sol-gel co-poly-condensation of the TEMPO-funcionalized alkoxide thereby obtained with methyl-trimethoxysilane (MTMS) catalyzed by fluoride (Figure 6.2). 

Figure 4 Polymer-silica hybrid materials hydrogen bonding between silanol groups of hydrolyzed silicon alkoxides and carboxylate groups of preformed poly(A, A-dimethylacrylamide) (a) or in situ polymerized A, A-dimethylacrylamide/methylene bisacrylamide precursors (b) favors the formation of homogeneous organic-inorganic networks...

Keywords Hybrid material Silica Polyelectrolyte adsorption Poly(vinylamine-co-vinylformamide)... 

Me K, Pang W, Wang Y, Lu F, Zhu Q (2005) Effects of specific bonding interactions in poly (8-caprolactone)/silica hybrid materials on optical transparency and melting behavior. Matra-... 

Highly dispersed polypropylene (PP)-Si02 hybrid materials [31-39] were synthesized upon grafting para-vinylphenylsulfonylhydrazide (which is a polymerizable foaming agent) onto the silica nanoparticles [40], Also, the use of poly(propylene maleic anhydride) copolymer was reported, which provided a higher adhesion between the PP matrix and Si02 nanoparticles [41]. 

Sugimoto H, Daimatsu K, Nakanishi E, Ogasawara Y, Yasumura T, Inomata K (2006) Preparation and properties of poly(methylmethacrylate)-silica hybrid materials incorporating reactive silica nanoparticles. Polymer 47(11) 3754—3759... 

Poly(vinyl-acetate), the polymer chosen for this study, is functionally incapable of covalently bonding with the polymerizing silicon alkoxide, TEOS. Therefore, the Si02/PVAc composites may be considered class I hybrid materials. Reasons for interest in mixing PVAc with silica include its excellent optical transparency, a refractive index close to that of silica, and its solubility in ethanol-water mixtures. The solubility of PVAc in ethanol-water mixtures allows the polymer to be added directly to a typical alkoxide sol-gel formulation of alkoxide, alcohol, water, and catalyst, followed by tiie polymerization of the inorganic network around the organic polymer domains. 

---