ORMOCERs

If the hydrolyses in organosilicate-polymer systems are carried out with increased amounts of the silicate, bicontinuous phases can be obtained (with the silica and polymer phases interpenetrating one another) [213]. At still-higher concentrations of the silicate, the silica generated becomes the continuous phase, with the polymer dispersed in it. The result is a polymer-modified ceramic, variously called an "ORMOCER" [214,215], "CERAMER" [216,217], or "POLY-CERAM" [218,219]. It is obviously of considerable importance to determine how the elastomeric phase modifies the ceramic in which it is dispersed. 

Oliveira P.W., Krug H., Kunstle H., Schmidt H., The production of Fresnel lenses in sol-gel derived ormocers by holography, SPIE Proc. 2288, 554-562, (1994). 

A research institute with a long tradition in the development of industrial inorganic and hybrid coatings, which owns the trademark ORMOCER. See www.ormocer.de. 

Note 2 Though it is a commonly used acronym for organically modified ceramic, Ormocer is a registered trademark and as such its terminological use is strongly discouraged. 

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. 

An ORMOCER is made from alkoxysilanes, which hydrolyzes in the following... 

If part of the R groups do not hydrolyze then ORMOCERs are obtained. A functionalized group (F) such as a photochrome, or a nonlinear optical active group may be introduced as shown in Scheme 25 64. 

Fig. 21. Scratch resistance of the nanocomposite coating depending on the thickness in comparison to a conventional Ormocer coating, ref. [22]...

Also other oxides such as for example Z1O2 were reacted in solution with other organic compounds to form amorphous hybrid composites. The name Ormocers (organically modified ceramics) was then used by Schmidt for these new materials. 

One can say that material research began to develop with the idea that molecular engineering may be induced directly or oriented from starting compounds. Ormosil and Ormocer [52] and carbon- [53,54] or nitrogen- [20,55] containing glasses are some applications of this concept. 

In the same year, 1986, the ormocers were presented to the public. These coatings are sprayed in a thickness of nm onto window glass and darken this when the sun shines on it. In the 1990s, these nanoscale powders were also used in silicate ceramics applied to tiles, sanitaryware and tableware articles or roofing tiles, they make sure that dirt particles caimot attache themselves to the surface. Special compositions even have an anti-bacterial effect. 

Another thing that follows from this is that occasional recent claims from manufacturers of the invention of a completely new type of materials are incorrect. Thus, both giomers and ormocers are types of composite resin, albeit with novel fillers and, in the case of ormocers, novel monomers, though they still set by the same type of chemistry, ie, addition polymerization [45]. They are also fundamentally hydrophobic, and do not form inherent bonds to the tooth surface. These materials are discussed later in the book, in Chapter 3, where their principal features are described and related to their essential chemistry as types of composite. 

As well as conventional composites of the type based on bisGMA and/or UDMA and filled with silicate-based filler, there are now materials available that are essentially composites in that they comprise a polymeric matrix reinforced with finely divided filler. However, either the polymer system or the filler phase is of a different chemical composition from that of conventional composite resins. Three such materials are currently available, and these are the ormocers, the siloranes and the giomers. Their details are given in Table 3.3, and their characteristics are described in the following subsections. 

The term ormocer derives from organically modified ceramic and these materials were developed at the Fraunhofer Institute, Wurzburg, Germany. Their original use was as speciality coatings for various technical applications, such as protective coatings. 

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