Reinforced-plastic material with

Thick laminates are obviously much less affected than thin ones in a given period and this explains the durability of many early reinforced plastics structures. It has been calculated that an epoxy-based reinforced plastics material with a typical diffusivity towards moisture of lO m s would require 13 months to reach saturation if left in a tropical climate at 35°C and 95% relative humidity (RH) if the thickness was 2 mm, but a 90 mm thick section would need 1342 years. During the approach to saturation, there is a through-the-thickness variation in moisture content and therefore in properties. 

Chang C-S (2006) Turning of glass-fiber reinforced plastics materials with chamfered main cutting edge carbide tools. J Mater Process Technol 180(1-3) 117-129... 

An incorporated technical organization founded in 1937 and serving the needs of the entire plastics industry in the U.S. It establishes standards for the properties and selection of materials and for product design and engineering. Its two major publications are the Plastics Engineering Handbook and the Reinforced Plastics Handbook. With it are associated the Plastics Pipe Institute and the Reinforced Plas-tics/Composites Institute. It is located at 1801 K ST NW, Suite 600K, Washington DC 20006. Website http //www.socplas.org. 

Epoxy resins continue to be essential preliminary products for the manufacturing of fiber-reinforced compound materials with glass, carbon or plastic fibers imbedded. As far as their mechanical properties are concerned, they can compete with metal materials, for example, in car manufacturing, boat building and aircraft construction. 

It is also found that in short-fiber-reinforced plastics the impact strength is maximum when the fiber length has the critical value. The requirements for maximum impact strength (i.e., short fiber and relatively weak interfacial bond) are thus seen to be contrary to those for maximum tensile strength (long fibers and strong bond). The structure of a reinforced plastic material should therefore he tailored in accordance with the service conditions to be encountered by the material. 

A reaction between the reinforced plastics material and the surrounding medium is defined here as an event which breaks and makes new covalent chemical bonds in the participating substances. One illustration is the hydrolysis reaction which breaks ester and amide groups in polyesters, polyamides and certain polyurethanes, when they are exposed to dilute acids or alkalis. Another example is the oxidation reaction that attacks carbon fibres whenever they are in contact with dilute nitric acid, acid/ dichromate, hypochlorite solutions, and so on. Such reactions can easily be foreseen and avoided by the use of more appropriate resins, fibres, and so on. The rate of chemical reactions involving resins is much more difficult to predict and they can sometimes be so slow that the effects are not necessarily unacceptable at ambient temperatures. One obvious illustration is the... 

Fatigue strength of reinforced plastic materials is generally explored with laboratory tests of specimens in cycling machines. Test specimens are specially prepared or cut from the full structure. Such tests, however, cannot provide accurate information about the durability of a complete structure under actual operating conditions. Thus composite structures are sometimes built and subjected to full scale testing. The subject of fatigue is discussed fully in Chapter 5. 

A fiber reinforced composite material with a polymer matrix will typically absorb moisture in a humid environment and at elevated temperatures. Combined exposure to heat and moisture affects reinforced plastics in a variety of ways. First, the hygrothermal swelling causes a change in the residual stresses within the composite that could lead to microcrack forma-... 

Various approaches exist to increase the electrical conductivity of plastic materials with nanoparticles [70,71]. The precipitation of nanometal particles to the reinforcing fibres is a very effective approach to achieve a good electrical conductivity at low concentrations. Pt was used as a model metal particle to avoid oxidation on processing by extmsion and injection moulding. Stable suspensions of Pt (supplied by Tsutomu Sakai, KRI Inc., Japan) [72] were applied in two concentrations suspension 1 150 mg Pt/L, suspension 2 1500 mg Pt/L, both containing particles of the size between 2 and 5 nm (Figure 5.17). The fibres were immersed... 

Table L.l Strength of Laminates made with Style 181 Glass Fabric (Ref Harper, C.A., Laminates and Reinforced Plastic Materials and Processes " Handbook of Plastics, Elastomers, and Composites, 3 ed., C.A. Harper, ed., McGraw-Hill, New York, 1996)...

A large amount of research has been reported on the mechanical properties of CNT reinforced plastic materials. In the early days, pristine CNTs were mostly used to fabricate CNT nanocomposites. The PMMA nanocomposites were prepared by melt blending, and the nanotubes were well dispersed in the matrix with no apparent damage or breakage. The storage modulus of the PMMA matrix is significantly increased by the incorporation of pristine MWNTs, particularly at high temperatures [90]. 

The ratio of 0.5 and 0.7 is not arbitrary, as it may appear, for small vehicles can normally be designed with W/D ratios of 0.5 or less, and vehicle displacements can become quite large as their W/D ratios approach 0.7. Using these values permits making meaningful comparisons of the depth potential of various hull materials. An examination of the data reveals that for all the metallic pressure-hull materials taken into consideration, the best results would permit operation to a depth of about 18,288 m (20,000 ft.) only at the expense of increased displacement. The nonmetallic materials of reinforced plastics (those with just glass-fiber-TS polyester) and glass would permit operation to 20,000 ft. or more with minimum-displacement vehicles. 

For over 40 years Reinforced Plastics has been reporting on developments in the reinforced plastics indust. With top management contacts in all the major materials and equipment companies and the most influential fabricators/moulders and end users. Reinforced Plastics magazine is the place to look for authoritative business news, topical feature articles and the facts behind the issues affecting your industry. 

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