ORMOCER materials

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. 

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. 

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. 

S. Kahra, A. Singh, M. Gupta, V. Chadha, Ormocer an aesthetic direct restorative material, Contemp. Clin. Dent. 3 (2012) 48-53. 

Keywords Inorganic-Organic Copolymer / Hybrid Material / ORMOCER / Sol-Gel / Functional Coatings... 

An alternative approach to conductivity enhancement by crystallinity supression is by the incorporation of inert fillers such as ceramic composites [77]. Another class of materials in which both polymer and organic materials are present are the so-called Ormocers [78] or Ormolytes [79]. These are produced by a sol-gel process in which amino-alkylsilanes are hydrolysed and condensed, and triflic acid (for proton electrolytes) or lithium perchlorate complexed with ethylene glycol diglycidyl ether (for a Li electrolyte) is incorporated. 

Moszner, N., Gianasmidis, A., Klapdohr, S., Fischer, U.K., Rheinberger, V. Sol-gel materials 2. Light-curing dental composites based on ormocers of cross-hnking alkoxysilane methacrylates and further nano-components. Dent. Mater. 24, 851-856 (2008)... 

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