Organic composite materials

Finally there are the composite materials that are not uniform but do have identifiable component parts. These component parts can usually be separated and analyzed individually. However, this is not always the chosen procedure for their analysis. Analytical pyrolysis has been applied to composite materials as well as to uniform polymers, depending on the purpose of the analysis. Some examples of the pyrolytic analysis of natural organic composite materials are presented in Part 3 of this book. 

Furthermore, exploitation of fundamental coordination chemistry for solid state synthesis affords a variety of metal ions with preferred coordination geometries and numerous ligand architectures for the construction of metal-organic composite materials. Such hybrid inorganic-organic materials exhibit useful physical properties with applications to optics," magnetism," transport," thermochromism," and conductance. ... 

Zhang J, Li B, Wang Z et al. Functionalized inorganic-organic composite material d ivated by sol-gel for construction of mediated amperometric hydrogen peroxide biosensor. Analytica Chimica Acta 1999 388 71-78. 

Another approach was the synthesis of inorganic/organic composite materials to influence the properties of the membrane. An overview on the state of the art of composite perflourinated membranes is given in [15]. Infiltration of a polymer carrier material with various inorganic proton conductors is subject of a patent [16]. For operation at elevated temperature, several materials have been considered, hi an early work, Nafion /Fl3P04 showed better conductivity at temperatures above 100°C compared with blank Nation and also reduced methanol permeabihty [17]. New types of polymers are also under development for better temperature stabihty one of the most advanced examples is the high-temperature material polybenzimidazole, which usually is doped with phosphoric acid [18]. 

The concept of using composites with polyaniline can be used to detect other gases, such as hydrogen sulfide (H2S). Hydrogen sulfide is a very weak acid with a pK, of 7 and it cannot dope polyaniline directly. About 10 times as much weak acid is required to dope poiyaniline when compared to a strong acid (20). One way to enhance the sensitivity of polyaniline to H2S is to use inorganic-organic composite materials. 

Studies of crystallization in emulsions and microemulsions are part of a new area of materials research, the aim of which is to produce advanced inorganic, organic, and inorganic-organic composite materials with well-defined properties. The research has been inspired by biomineralization, i.e., the strategies that living organisms use to form their skeletons or store minerals for various purposes. 

Schmidt HK. Synthesis and applications of in-organic/organic composite materials. Macro-mol Symp 1996 101 333 2. 

Removal of surfactant from the inorganic-organic composite materials after synthesis is generally conducted via calcination in an air flow at high temperatures. However, this procedure often leads to film distortion or even crack formation... 

To discuss hybrid inorganic-organic composite materials, a brief review of sol-gel chemistry is necessary. Since this section focuses on silicate and silsesquiox-ane chemistry, the review of sol-gel chemistry will be limited to detailing some of the nuances associated with silicate alkoxides. After the brief review of sol-gel chemistry, we will present methods for the preparation of hybrid inorganic-organic composite materials, followed by a brief discussion of polyimide-based hybrid composites. 

Schmidt, H. and Krug, H. (1994) Sol-gel-based inorganic organic composite materials, in Inorganic and Orgartometallic Polymers II Advanced Materials and Intermediates (eds P. Wisian-Neilson, H.R. Allcock, and K.J. Wynne), American Chemical Society, Washington, DC,... 

The development of mineral-organic composite materials offers the possibility of combining the favorable properties of bioceramics such as the HAP, alumina or titanium dioxide with the molding capacity of biocompatible polymers (polymethylmethacrylate) PMMA [KHO 92], poly(L-lactic) acid PLLA [ROD 95], poly (ethylene) PE pOW 91]). It is also conceivable to attain a value of the modulus of elasticity near to that of the bone. 

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