Crosslinked siloxanes

Covalently crosslinked siloxane containing liquid crystalline networks with elastic properties were prepared 349). In all of the networks liquid crystalline phases of the linear precursors were retained. For low degrees of crosslinking the phase transition temperatures remained nearly unchanged, whereas higher degrees of crosslinking reduced the phase transition temperatures. 

While other high refractive index crosslinkable methacrylate monomers are reported in the patent literature, this application entails polymerizing four monomers one of which contains a crosslinkable siloxane or fluoro-containing component. 

Fujiki M, Furuta D, Naito M (2004) Manufacture of semi-IPN (interpenetrating polymer network) composite and the composite made of crosslinkable siloxane and radically polymerized polymer. JP Patent 2 004 263 062... 

Arkles BC, Smith RA (1990) Secondary crosslinked siloxane semiinterpenetrating polymer networks and methods of making them. US Patent 4 970 263... 

Vulcanization is a term for the crosslinking of an elastomer. Other terms for specific applications include curing (e.g., crosslinking siloxane caulking... 

Scheim U, Ziche W. (2006) Crosslinkable siloxane urea copolymers for molding compositions (Wacker-Chemie G.m.b.H., Germany) W02006010486. 

Quenching with the aminated resin appeared absolutely necessary to avoid cleavage of the aminopropylpolysiloxane. After filtration, the aminopropyl-polysiloxane can be stored at -18°C in the CH Cl /MeOH solution without decomposition. Analysis by SEC can be made from THE solutions prepared after incomplete evaporation of the CH Clj/methanol mixture. Actually, they cannot be easily stored for long times and the polymers cannot be dried without degradation. Their sensitivity to TMSI appeared much higher compared with NBoc-functionalized hyperbranched poly(siloxysilanes) or NBoc-functionalized highly crosslinked siloxanes networks formed by sol-gel chemistry [27]. 

Partially crystalline behavior at low temperature (endothermic melting peaks in DSC at approximate -50 °C) is observed for weakly crosslinked siloxane particles and the corresponding graft copolymers. 

For viscosity adjustment of crosslinkable siloxane oligomers reactive monomers are added. Thus, the viscosity of the siloxane oligomer at 80°C can be reduced from 15 Pa s to 1 Pa s (Fig. 7). 

Ekin, A. Webster, D. C., Combinatorial and high-throughput screening of the effect of siloxane composition on the surface properties of crosslinked siloxane-polyurethane coatings, J. Comb. Chem. 2007, 9, 178-188... 

Figure 15.21 The synthesis of silica reported by Corriu et al. from an extensively crosslinked siloxane system by the crosslinking of diacetylene units...

Apart fi-om the peroxide curing method as discussed above, there are several other ways to crosslink siloxane polymers. These rely on coupling reactions between reactive functional groups that have been deliberately introduced either as end-groups or in the side-chain of the pol3nner. Representative examples of such fimctional-group- containing polysiloxanes are shown in Fig. 6.19. 

Additives used in final products Fillers aluminum, barium sulfote, aluminum hydroxide, glass fiber, mica, montmorillonite, Ni-BaTi03, nickel, silica, titanium dioxide, titanium fiber Plasticizers di-(2-ethylhexyl) phthalate, 2-hydroxyethyl methacrylate, 4-cyanophenyl 4-heptylbenzo-ate Antistatics copper dimethacrylate, glycerol monolaureate, indium tin oxide, lauramide diethanolamide, polyaniline, polypyrrole Antiblocking crosslinked siloxane particles Release magnesium stearate, methylpolysilsiquioxane, silicon nitride, stearic add Slip emcamide, slip ... 

Tospearl particles are crosslinked siloxanes made by the controlled hydrolysis and condensation of methyltrimethoxysilane. Their spherical nature, narrow particle size distribution and chemical and thermal stability make them ideal for use in wear resistance, antiblocking and light diffusing applications. 

HIGH CONDUCTIVITY IN AN AMORPHOUS CROSSLINKED SILOXANE POLYMER ELECTROLYTE... 

To produce stable nanostructures, the obtained silicone materials should form a densely crosslinked siloxane network. Therefore, the precursor should preferentially possess three reactive functions in its chemical structure (T-unit). Methyltrimethoxysilane (MeSi(OMe)3) can serve as a typical precursor of that kind (see Figure 4.3). The stiffness of the material can be enhanced by increasing the crosslinking density. 

Crosslinked Siloxane via Hydro ilatior> Cure Chemistry "Silicone Elastomer"... 

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