Composites material combinations

Glass-reinforced plastic (GRP) is an example of a composite material combining the properties of two different materials. It is made by embedding short... 

MMCs are typically alloys of aluminum reinforced with ceramic particles (usually silicon carbide). This composite material combination has the lightness of aluminum but the strength and temperature resistance of cast iron. Consequently, MMCs have tremendous potential in the automotive and aerospace industries for the replacement of cast iron to considerably reduce weight. 

Nonwoven products are often composite materials combining the nonwoven with polyethylene film, for example. 

To improve collagen s potential as a biomaterial, it has been modified or combined with other resorbable polymers. Modifications like cross-linking, addition of bioactive molecules, and enzymatic pretreatment have resulted in novel coUagen-based materials with improved fimctionality [10, 11]. Moreover, to facilitate the formation of fibers for biomedical textile applications, composite materials combining coUagen with other resorbable polymers like PLA, PLGA, and PCL have been studied extensively [12-15]. 

Ferroelectric Ceramic—Polymer Composites. The motivation for the development of composite ferroelectric materials arose from the need for a combination of desirable properties that often caimot be obtained in single-phase materials. For example, in an electromechanical transducer, the piezoelectric sensitivity might be maximized and the density minimized to obtain a good acoustic matching with water, and the transducer made mechanically flexible to conform to a curved surface (see COMPOSITE MATERIALS, CERAMiC-MATRix). 

Finally, the combined reinforcing effect and high absorption capacity of asbestos fibers have been exploited in a variety of appHcations to increase dimensional stabiHty, typically in vinyl or asphalt tiles and asphalt toad surfacing. Figure 9 summarizes, as of 1984, the various classes of application for asbestos fibers in combination with other materials. The diagram shows that in recent years, most industrial appHcations have evolved towards composite materials where the fibers are bonded within an organic or inorganic matrix. 

The term composite materialis used to describe macroscopic combiaations of two or more materials. Macroscopic combiaations are specified to exclude alloys that consist of materials combined on a microscopic scale (1). Such an exclusive definition of composite materials is not universal, but it is commonly accepted and it helps restrict to a manageable size an introductory treatment of the science and technology of composite materials. 

A polymer blend is a physical or mechanical blend (alloy) of two or more homopolymers or copolymers. Although a polymer blend is not a copolymer according to the above definition, it is mentioned here because of its commercial importance and the frequency with which blends are compared with chemically bonded copolymers. Another technologically significant material relative to the copolymer is the composite, a physical or mechanical combination of a polymer with some unlike material, eg, reinforcing materials such as carbon black, graphite fiber, and glass (see Composite materials). 

Gl ss-Ionomers. Glass-ionomers show fluoride release at levels that are usually higher than those found in composite materials. The fluoride is found within the aluminosihcate glass, which is melted with fluoride fluxes and ground to form powder filler. The fluoride is added as calcium fluoride [7789-75-5] aluminum fluoride [15098-87-0] and sodium fluoride [7681-49-4] in a combined proportion of approximately 20% by weight in the final powder (284,285). 

Catalysts vary both in terms of compositional material and physical stmcture (18). The catalyst basically consists of the catalyst itself, which is a finely divided metal (14,17,19) a high surface area carrier and a support stmcture (see Catalysts, supported). Three types of conventional metal catalysts are used for oxidation reactions single- or mixed-metal oxides, noble (precious) metals, or a combination of the two (19). 

Metal composites Many combinations available properties vary widely depending on materials used. 

Today, carbon fibers are still mainly of interest as reinforcement in composite materials [7] where high strength and stiffness, combined with low weight, are required. For example, the world-wide consumption of carbon fibers in 1993 was 7,300 t (compared with a production capacity of 13,000 t) of which 36 % was used in aerospace applications, 43 % in sports materials, with the remaining 21 % being used in other industries. This consumption appears to have increased rapidly (at 15 % per year since the early 1980s), at about the same rate as production, accompanied by a marked decrease in fiber cost (especially for high modulus fibers). 

The manufacture of sintered parts such as gears and bushings and that of composite materials are, in a sense, also applications of particle adhesion. After all, a sintered part is simply a part manufactured from a powder that has been subjected to conditions that would encourage the particles to strongly cohere. Similarly, a composite material is one where particles of one or more materials are combined in some fashion so as to adhere within a matrix, thereby imparting certain properties to the composite that none of the materials possess in their own right. 

Laminated composite materials consist of layers of at least two different materials that are bonded together. Lamination is used to combine the best aspects of the constituent layers and bonding material in order to achieve a more useful material. The properties that can be emphasized by lamination are strength, stiffness, low weight, corrosion resistance, wear resistance, beauty or attractiveness, thermal insulation, acoustical insulation, etc. Such claims are best represented by the examples in the following paragraphs in which bimetals, clad metals, laminated glass, plastic-based laminates, and laminated fibrous composite materials are described. 

Particulate composite materials consist of particles of one or more materials suspended in a matrix of another material. The particles can be either metallic or nonmetallic as can the matrix. The four possible combinations of these constituents are described in the following paragraphs. 

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