Hybrid siloxane network polymers

Hybrid Siloxane Network Polymers From Hydrosilation Reactions... 

Brus, J. Dybal, J., Solid-State NMR Study of Structure, Size and Dynamics of Domains in Hybrid Siloxane Networks. Polymer 2000,41, 5269-5282. 

Hybrid versions of silicone-thermoplastic semi-IPNs have been developed (19). A hybrid interpenetrating network is one in which the cross-linked network is formed by the reaction of two polymers with structurally distinct backbones. Hydride-functionalized siloxanes can be reacted with organic polymers with pendant unsaturated groups such as polybutadienes (5) in the presence of platinum catalysts. Compared with the polysiloxane semi-IPNs discussed earlier, the hydride IPNs tend to maintain mechanical and morphologically derived properties, whereas properties associated with siloxanes are diminished. The probable importance of this technology is in cost-effective ways to induce thermoset characteristics in thermoplastic elastomers. 

Keywords Polymers / Hybrid Organic-Inorganic Polymers / Polymer Network / IPN / Hybrid Polymer Technologies / Contact Lenses / Coatings / Surfactants / Wetting Agents / Silicones / Silicone Polyimides / Siloxane Resins... 

Silicone co-polymer networks and IPNs have recently been reviewed.321 The development of IPNs is briefly described, and the definitions of the main (non-exclusive) classes of the IPNs are cited. Examples of latex IPNs, simultaneous and sequential IPNs, semi-IPNs, and thermoplastic IPNs are provided. The use of silicone-silicone IPNs in studies of model silicone networks is also illustrated. Networks in which siloxane and non-siloxane components are connected via chemical bonds are considered co-polymer networks, although some other names have been applied to such networks. Today, some of the examples in this category should, perhaps, be discussed as organic-inorganic hybrids, or nanocomposites. Silicone IPNs are discussed in almost all of the major references dealing with IPNs.322-324 Silicone IPNs are also briefly discussed in some other, previously cited, reviews.291,306... 

In the case of aU of the developed hybrid silarylene-siloxane and carboranylenesiloxane polymers, an evaluation of the nature of different phases containing aromatic or carborane groups will be illuminating to understand what contribution does each distinct phase has on the elasticity and other material properties of the generated networks. Other in-depth mechanical studies are also in order to better evaluate the high temperature elasticity of the materials. 

A new convenient polymer modification has been developed to synthesize a series of novel silanol-containing polymers by a selective oxidation of Si—containing precursor polymers with a dimethyldioxirane solution in acetone. The silanol hydrogen bonding interactions in polymer blends as well as the silanol self-condensation to form siloxane semi-interpenetrating polymer networks in miscible polymer blends and organic-inorganic polymeric hybrids are discussed. 

Other chemical modifications include the introduction of siloxane, reaching an organic-inorganic hybrid material [43, 44]. It can be added in the polymer backbone or also as pendant group. This approach consists in the generation of interpenetrating networks which increase the thermal stability of the material [45]. 

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