Silane monomer

Catalysis. Platinum-catalyzed hydrosilation is used for cross-linking siUcone polymers and for the preparation of functionally substituted silane monomers (250). The most widely used catalyst is chloroplatinic acid (Spier s catalyst), H2PtCl3. Other compounds that catalyze the reaction include Pt(Il)... 

There are reactive softeners, some of which are N-methylol derivatives of long-chain fatty amides (10.241) while others are triazinyl compounds (10.242). The N-methylol compounds require baking with a latent acid catalyst to effect reaction, whereas dichloro-triazines require mildly alkaline fixation conditions. The N-methylol compounds are sometimes useful for combination with crease-resist, durable-press, soil-release and water-repellent finishes. In this context, the feasibility of using silane monomers such as methyltri-ethoxysilane (10.243), vinyltriethoxysilane (10.244), vinyl triace tylsilane (10.245) and epoxypropyltrimethoxysilane (10.246) in crosslinking reactions to give crease-resist properties and softness simultaneously has been investigated [492]. 

Like monodisperse carbosiloxane dendrimers, hyperbranched carbosiloxanes can be produced by hydrosilylation [100]. The first compounds of this kind were synthesised in 1991 by Mathias and Carothers [101] by polymerisation of an al-lyl-tris(dimethylsiloxy)silane monomer with addition of chloroplatinic acid hydrate (Fig. 4.52). The reaction proceeds relatively fast however, addition of more catalyst does not increase the molecular masses (19000 g/mol). The NMR spec-... 

Pt-catalyzed copolymerization of ferrocenylsilane and SCB, disilacyclobutane, or cyclic silane monomers can be accomplished to provide random copolymers (Scheme 17) <1996MAR319, 1995MM401>. 

Preparation procedure of silica monoliths from silane monomers. 169... 

PREPARATION PROCEDURE OF SILICA MONOLITHS FROM SILANE MONOMERS... 

The second method of application was to dip the specimens in the silane monomer and allow them to dry at room temperature. Add-ons of... 

The scheme of the chemical composition of the ceramic ink is visible in Fig. 11. Component A denotes the surface-modified coloring pigments, B the silane oligomers, C the Si02 nanoparticles, and D the silane monomers. 

The presence of small amounts of urea impurity in the bis(ureido)silane monomer could be determined readily by NMR spectroscopy because the chemical shifts of the tetramethylene group in urea and bis(ureido)silane are considerably different (9). 

Preparation of Silphenylene-Siloxane Polymers. The basic reaction for the preparation of exactly alternating silphenylene-siloxane polymers from bis(ureido)silanes, Va-Vh, and the disilanol monomer is step-growth polymerization. This reaction was carried out at -20 °C, at which temperature the possible side reactions described previously can be prevented or at least decreased in rate. To obtain a high-molecular-weight polymer, a solution of the bis(ureido)silane monomer was added slowly to a slurry of the disilanol monomer in chlorobenzene (ii). After addition of 95%... 

The first use of functionalised silane monomers in the preparation of metal oxide imprinted gels came in the mid 1980s with the work from Glad et al. [36] and from... 

Surface-functionalised gels were also prepared by Wulff et al. using diimine silane monomers [37]. The researchers were interested in isolating the effect of functional group positioning in molecularly imprinted materials. By using a... 

The density of cross-linking can be adjusted by co-condensation of multialkoxy-silane monomers, such as [Me(EtO)2(CH2)2SiMe2]0 or [Me(Et0)2(CH2)2SiMc20]4. DSC and TGA analyses did not show much difference in the amount of unreacted sSiOH or reduction of thermal resistance. 

In addition, VTMS hydrolyzes to a much eater extent than MTMS, an expected pattern similar to the /sopropoxy examples. Clearly the bulk of the Mopropoxy groups on the hindered silanes is very beneficial in protecting the silane from premature reaction during latex polymerization, when compared to the more traditional methoxy substituted silane monomers. This has implications for the ultimate properties of the final films, as the stability of the isopropoxy silanes allows levels of incorporation, and thus final performance, that are sinq)ly not available when using methoxy-substituted silane monomers. 

Overall, it is clear that significant hydrolysis of silanes in waterborne formulations occurs when the hindered silanes are used as monomers in emulsion polymerization. Si NMR spectroscopy on latex solids also reveals that a significant amount of hindered vinyl silane monomer forms condensates with itself, so that not all of the vinyl groups are incorporated into the backbone of the growing polymer through free-radical polymerization. 

The bulk of the isopropoxy groups on the vinyl and methacryl silanes is unique among silane monomers in that, through their enhanced stability, levels of incorporation of silane an order of magnitude greater than standard methoxy-substituted monomers is possible. Thus, much higher performance can be achieved using these silane monomers. 

D.T. Liles, D. L. Murray, US Patent 5 932 651. The authors suggest that the silane monomers may exist primarily as silanol after polymerization. 

We have prepared chemically modified mesoporous catalytic materials via three routes (i) surface modification of preformed gels via chlorination in a fluidised bed reactor (ii) surface modification of preformed gels via silylation (iii) sol-gel techniques based on preformed silane monomers (Figure 1). Further chemistry on the surface of the materials is achieved by conventional solution methods or by further reaction in the vapour phase. 

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