Reinforced plastics applications

As of this date, there is no lithium or alkyl-lithium catalyzed polyisoprene manufactured by the leading synthetic rubber producers- in the industrial nations. However, there are several rubber producers who manufacture alkyl-lithium catalyzed synthetic polybutadiene and commercialize it under trade names like "Diene Rubber"(Firestone) "Soleprene"(Phillips Petroleum), "Tufdene"(Ashai KASA Japan). In the early stage of development of alkyl-lithium catalyzed poly-butadiene it was felt that a narrow molecular distribution was needed to give it the excellent wear properties of polybutadiene. However, it was found later that its narrow molecular distribution, coupled with the purity of the rubber, made it the choice rubber to be used in the reinforcement of plastics, such as high impact polystyrene. Till the present time, polybutadiene made by alkyl-lithium catalyst is, for many chemical and technological reasons, still the undisputed rubber in the reinforced plastics applications industries. 

A third interesting aspect of this story is that Du Pont s aramide fiber was not specifically the result of market-driven research. When this fiber was patented in 1971 there was no commercial application in view. However, within ten years, three varieties of Kevlar fiber were commercialized by Du Pont for dozens of reinforced plastic applications in radial passenger tires, belts, in protective clothing, such as gloves or ballistic and flak vests, in ropes and cables in racing kayaks and canoes, and in commercial aircraft. Thus the Kevlar fiber by no means resulted from the functional, bottom-up, approach which is sometimes considered as a major characteristic of materials science. The aramide fiber resulted from the traditional style of industrial research which was successful in the plastic era and confirms the leadership of chemistry in materials technologies. 

Aramid fibres absorb about 5% water, which can sometimes affect then-performance in aqueous liquids [24]. Some reinforced plastics applications involve repeated soak-dry cycles and it can be the drying stage, rather than absorption that causes damage. If the second absorption cycle produces more absorption in a given time than the first cycle did, it usually indicates permanent damage. 

Fiberglass-based roofing shingles are similar to reinforced plastics applications and require durable organic polymers to resist the sun and other degradative effects. Vinylbenzylaminosilane has been used in formulations to allow the products to meet the requirements of building codes and construction standards. 

Transatlantic Plastics Ltd A B C Fothergill a Harvey Ltd Reinforced Plastics Applications (Swansea)... 

Plastic Coating Equipment Ltd Plastic Coatings Ltd Plastic Constructions Ltd Plastic Dipping Co Ltd Plastic Dip Mouldings Ltd QD Plastics (Glasgow) Ltd Reinforced Plastics Applications (Swansea) Ltd Resistoid Ltd... 

Pritex (Plastics) Ltd QED Design 8 Development Ltd Reinforced Plastics Applications (Swansea) Ltd Rubbarite Ltd Rubber Plastics Ltd Screenprints (Vacuum Formers) Ltd Serk (R 8 D)... 

Wood and Wood-Lined Steel Pipe Douglas fir, white pine, redwood, and cypress are the most common woods used for wood pipe. Wood-lined steel pipe is suitable for temperatures up to 82°C (180°F) and for pressures from 1.4 MPa (200 Ibhin ) for the 4-in size, through 0.86 MPa (125 IbFin ) for the 10-in size, to 0.7 MPA (100 Ibf/ in") for sizes larger than 10 in. For fume stacks and similar uses, wood-stave pipe with rods on 0.3-m (1-ft) centers is most satisfactory because it permits periodic tightening. In recent years reinforced plastics have supplanted wood pipe in most applications. 

A development of interest to the chemical industiy is the tubular precipitator of reinforced-plastic construction (Wanner, Gas Cleaning Plant after T1O2 Rotary Kilns, technical bulletin, Lurgi Corp., Frankfurt, Germany, 1971). Tubes made of polyvinyl chloride plastic are reinforced on the outside with polyester-fiber glass. The use of modern economical materials of construction to replace high-maintenance materials such as lead has been long awaited for corrosive applications. 

World production of unsaturated polyester resins in 1997 was of the order of 1.7 X 10 tonnes, with the USA accounting for about 45% and Western Europe 27%. Over 75% is used in reinforced plastics, with the rest being used for such diverse applications as car repair putties, cultured marble , wood substitution and surface coatings. The pattern of consumption in 1993 of reinforced polyesters in the USA was reported as ... 

One of the key factors which make plastics attractive for engineering applications is the possibility of property enhancement through fibre reinforcement. Composites produced in this way have enabled plastics to become acceptable in, for example, the demanding aerospace and automobile industries. Currently in the USA these industries utilise over 1(X),000 tonnes of reinforced plastics out of a total consumption of over one million tonnes. 

The friction and wear of plastics are extremely complex subjects which depend markedly on the nature of the application and the properties of the material. The frictional properties of plastics differ considerably from those of metals. Even reinforced plastics have modulus values which are much lower than metals. Hence metal/thermoplastic friction is characterised by adhesion and deformation which results in frictional forces that are not proportional to load but rather to speed. Table 1.7 gives some typical coefficients of friction for plastics. 

A wide variety of thermoplastics have been used as the base for reinforced plastics. These include polypropylene, nylon, styrene-based materials, thermoplastic polyesters, acetal, polycarbonate, polysulphone, etc. The choice of a reinforced thermoplastic depends on a wide range of factors which includes the nature of the application, the service environment and costs. In many cases conventional thermoplastic processing techniques can be used to produce moulded articles (see Chapter 4). Some typical properties of fibre reinforced nylon are given in Table 3.2. 

Willard H. Sutton, B. Walter Rosen, and Donald G. Flom, Whisker-Reinforced Plastics for Space Applications, SPE Joumai, November 1964, pp. 1203-1209. 

The purpose of this subsection is to familiarize the reader with some of the basic characteristics and problems of composite laminate joints. The specific design of a joint is much too complex for an introductory textbook such as this. The published state-of-the-art of laminate joint design is summarized in the Structural Design Guide for Advanced Composite Applications [7-5] and Military Handbook 17A, Plastics for Aerospace Vehicles, Part 1, Reinforced Plastics [7-6]. Further developments can be found in the technical literature and revisions of the two preceding references. 

Whichever application of natural fiber or natural fiber-reinforced plastics will be used depends on the different environmental conditions, which are likely to add to the aging and degrading effects. On the other hand, such effects are often desirable, as is the case with com-... 

The choice of manufacturing technology for the fabrication of fiber-reinforced plastics or composite materials is intimately related to the performance, economics, and application of the materials. It also depends upon a number of factors, such as component numbers required, item complexity, number of molded surfaces, and type of reinforcement. 

Fiber-reinforced plastics have been widely accepted as materials for structural and nonstructural applications in recent years. The main reasons for interest in FRPs for structural applications are their high specific modulus and strength of the reinforcing fibers. Glass, carbon, Kevlar, and boron fibers are commonly used for reinforcement. However, these are very expensive and, therefore, their use is limited to aerospace applications. 

For firewater, steel pipes are used but corrosion products can block sprinklers. Cement asbestos pipes are utilized but pressure limitations restrict their use. For critical applications, including offshore oil installations, cupronickel alloys and even duplex stainless steels are used. Fire-retardant grades of fiber-reinforced plastics are now available. 

In structural applications for plastics, which generally include those in which the product has to resist substantial static and/or dynamic loads, it may appear that one of the problem design areas for many plastics is their low modulus of elasticity. The moduli of unfilled plastics are usually under 1 x 106 psi (6.9 x 103 MPa) as compared to materials such as metals and ceramics where the range is usually 10 to 40 x 106 psi (6.9 to 28 x 104 MPa). However with reinforced plastics (RPs) the high moduli of metals are reached and even surpassed as summarized in Fig. 2-6. 

Rosato, D. V., and G. Lubin, Application of Reinforced Plastics, 4th International RP Conference. British Plastics Federation, London, UK. Nov. 25-27.1964. 

About 8,000 metric tons of peroxides were consumed in 1972. This consumption was strongly stimulated by the rapid growth in reinforced plastics (Ref 23). The largest volume product is benzoyl peroxide which is used in polystyrene and polyester markets for such items as toys, automobiles, furniture, marine, transportation and mil requirements. Also, methyl ethyl ketone peroxide is used in large volumes to cure (as a catalyst) styrene-unsatur-ated polyester adhesive resins used in mil ammo adhesive applications, as well as in glass fiber reinforced plastic products such as boats, shower stalls, tub components, automobile bodies, sports equipment, etc. The monoperesters are growing slowly because of some substitution of the peroxydicarbonates and azo compds (Refs 8,9 23)... 

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