Metal particle-polymer composite

Relaxational and Interfacial Properties of Fine Metal Particles-Polymer Composites... 

We found a new phenomenon In which the metal was uniformly dispersed Into the polymer in the form of line particles having diameters between 1-10 nm only by the heat treatment just above cryslallizalion temperature of the polymer. We named this new dispersion process the reiaxative auio-dispersion (RAO) process The melat-polymer composile prepared by the RAD process had various kinds of colors and interesting elecirical properties caused by the size effect of the meiat and the Interaction between the metal particles and the polymer matrix, in this paper, we will report reiaxative and Inierlacial properties of fine metal particle-polymer composites (MPPC Metal Powder-Polymer Composile) prepared by the RAD process. 

Recently, ultrafine metai particles have attracted much interest because of their unique properties which differ from those of buiK metals, e.g., quantum size effect, such as low melting point, plasmon resonance absorption and so an It is well known that ultrafine metal particles are quite active because of their large surface area and that they are liable to aggregate and grow in size. Thus, it is necessary to maintain them in stable form in a matrix for size control and tor narrow size distribution. Ultrafine metal partides-polymer composites, which are prepared by embedding ntetal particles in a polymer, can be used as electrical, magnetic, optical or chemically useful materials. The techniques to prepare ultrafine metal partides-polymer composites have been explored end reported by many researchers. Many of these involve co-evaporation or co-sputtering of a metal and polymer . In the case of thesb methods, however, metal-polymer composites have to be prepared at a rate below ca. 10 nm/min so that ultrafine metal particles will not... 

We have found quite a novel technique to make ultrafine metai particles-polymer composites The new technique consists of three steps. The first step is the preparation of the matrix polymer with a thermodynamicatly ntetastable structure.The second is the vacuum vapor deposition of the metal onto the matrix polymer. The last step is the heat-treatment of the polymer laminated with the thin rrtetal film. The metal disposes into the matrix polymer in the form of ultrafine particles through a series of treatments mentioned above. This dispersion process, named RAD Reiaxstive Auto-Oispersion), contains an intersting phenomenon of the solid phase dispersion. However, rto complete explanation has been offered about the actual dispersion mechanism yet. 

The TEM is one of the most generally useful microscopes many thousands of them ate in daily use throughout the world. They ate appHcable to the study of ultrafine particles (eg, pigments abrasives and carbon blacks) as well as microtomed thin sections of plant and animal tissue, paper, polymers, composites of all kinds, foods, industrial materials, etc. Even metals can be thinned to sections thin enough for detailed examination. 

The bonding agent technique is usually not applicable to the metal particles in the composite. However, the surface of the metal is almost invariably covered by a thin (40-80 A) oxide layer [50]. The free energy of oxide surfaces is normally quite large (10 mJ/m ) to allow quick wetting by most organic polymers (40-60 mJ/m ). Additionally, the metal surface may provide two... 

Note 6 Electric conductance of a nonconducting polymer can be achieved by dispersing conducting particles (e.g., metal, carbon black) in the polymer. The resulting materials are referred to as conducting polymer composites or solid polymer-electrolyte composites. 

Strength, brittleness, and solvent permeability properties are limited because of lack of control of the ceramic composition on a macro- and microlevel. Even small particle sizes are large compared with the molecular level. There have been a number of attempts to produce uniform ceramic powders including the sol-gel synthesis in which processing involves a stable liquid medium, coprecipitation in which two or more ions are precipitated simultaneously. More recently, Carraher and Xu have used the thermal degradation of metal containing polymers to deposit metal atoms and oxides on a molecular level. 

The reduction of rhenium salt in a PAN matrix and the formation of the polyconjugated polymer system proceed simultaneously and interdependently during IR-pyrolysis of a film. As result the thin film of carbon with ultra dispersed metal particles is formed on a surface of porous support (Fig. 2). The thickness of defectless Re-containing carbon film was 300 - 500 nm. The size of metallic particles was proved to be from 3 to 10 nm. The average content of rhenium in a metal-carbon composition was about 5 mass %. 

More recently, matrix-semiconductor composites, i.e., films comprising of semiconductor particles that are dispersed in a nonphotoactive continuous matrix, have been developed. Examples of matrix candidates are metals and polymers [411-416]. Occlusion electrosynthesis is a versatile method for preparing such composite films, as exemplified by the Ni-Ti02 and Ni-CdS family [417-419]. 

Among the specific characterizations needed for such modified conducting polymers, the determination of the metallic loading and of the atomic composition of the metallic particles inserted in the organic matrix are essential. 

Other conducting polymers can be investigated as supports for dispersing catalytic metallic particles. Shan and Pickup [21] used a composite of poly(3,4-ethylenedioxythiophene) and poly(styrene-4-sulfonate) (PEDOT/PSS) to disperse Pt particles. They compared the performances of such electrodes with carbon-supported Pt for the electroreduction of oxygen, and they found similar exchange... 

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