Hybridization materials

Producing aerogel-like materials without supercritical drying at all preparation of inorganic—organic hybrid materials. ... 

N. L. Hancox, (ed.). Fibre Composite Hybrid Materials, McMillan, New York (1981). 

By using a similar procedure for the preparation of hybrids of silica, hybrids materials consisting of other metal oxides were also prepared by the group of Wilkes [15]. For example, titania was incorporated into organic polymers by using the chemically controlled condensation (CCC) method for the preparation of poly(tetramethylene oxide)-silica or poly(dimethylsiloxane)-silica hybrids. Especially, in the case of the hybrid with poly (tetramethylene oxide), the modulus or ultimate strength of the hybrid increased in the presence of titania component, as shown in Table 3. This phenomenon was explained by the catalytic ability of... 

Noell et al. reported the preparation of silica-poly(ether ether ketone) hybrid materials with improved physical properties.155 An amine-end-capped poly(ether ether ketone) was used to react with isocyanatopropyltriethoxysilane in tetrahydrofuran (THF). The triethylsilane-end-capped poly (ether ether ketone) was mixed with tetraethoxysilane (TEOS) in THF. Quantitative amounts of water were introduced into die system, and the mixture was reduxed at 80°C. The entire reaction mixture was allowed to further react in Tedon molds. Tough transparent materials were obtained by diis approach. 

IV. SELF-DOPED POLYMERS, POLYMERIC COMPOSITES, AND HYBRID MATERIALS... 

Figure 13. (a) Substituted polypyrrole, (b) self-doped polypyrrole, (c) heteroaromatic polymer showing the monomer unit, (d) composite polypyrrole-polyelectrolyte, and (e) hybrid material. (Polyaniline macroion photo supplied by Gomez-Romero and M. Lira.)... 

Very recently, Wilkes and co-workers 330,331) have reported the preparation and characterization of hybrid materials, which they named as ceramers . Ceramers were synthesized through the incorporation of polymeric or oligomeric PDMS into silicate glasses by a sol-gel process as shown in Reaction Scheme XXIV. During these reactions the variables such as the type of the alkoxide used, amount of water added, the pH value of the reaction system, and the reaction temperature, were carefully monitored. 

Table 19 Compounds Ts[OSiMe2R]8 for hybrid material synthesis obtained from T8[OSiMe2H]s... 

Clays have long been used as fillers in polymer systems because of low cost and the improved mechanical properties of the resulting polymer composites. If all other parameters are equal, the efficiency of a filler to improve the physical and mechanical properties of a polymer system is sensitive to its degree of dispersion in the polymer matrix (Krishnamoorti et ah, 1996). In the early 1990s, Toyota researchers (Okada et ah, 1990) discovered that treatment of montmorillonite (MMT) with amino acids allowed dispersion of the individual 1 nm thick silicate layers of the clay scale in polyamide on a molecular. Their hybrid material showed major improvements in physical and mechanical properties even at very low clay content (1.6 vol %). Since then, many researchers have performed investigations in the new field of polymer nano-composites. This has lead to further developments in the range of materials and synthesizing methods available. 

PI nanocomposites have been prepared by various methods with different fillers. The nanocomposites might have many applications starting from barrier and thermal resistance to a compound with low coefficient of thermal expansion (CTE) [154-167]. These hybrid materials show very high thermal and flame retardation as well as barrier resistance and adhesion. Tyan et al. [158] have shown that depending on the structure of the polyimide the properties vary. Chang et al. [159] have also investigated the dependency of the properties on the clay modifiers. 

Depending on the level of interaction between these organic-inorganic phases, hybrid materials can either possess weak interaction between these phases such as van der Waals, hydrogen bonding, or electrostatic interaction [7,8], or be of strong, chemically bonded (covalent or coordinate) types [9]. 

Simon P.F.W., Ulrich R., Spiess H.W., and Wiesner U. Block copolymer-ceramic hybrid materials from organically modified ceramic precursors, Chem. Mater., 13, 3464, 2001. 

A New Class of Hybrid Materials via Salt-inclusion Synthesis... 

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