Structural fiber market

Because of their unique blend of properties, composites reinforced with high performance carbon fibers find use in many structural applications. However, it is possible to produce carbon fibers with very different properties, depending on the precursor used and processing conditions employed. Commercially, continuous high performance carbon fibers currently are formed from two precursor fibers, polyacrylonitrile (PAN) and mesophase pitch. The PAN-based carbon fiber dominates the ultra-high strength, high temperature fiber market (and represents about 90% of the total carbon fiber production), while the mesophase pitch fibers can achieve stiffnesses and thermal conductivities unsurpassed by any other continuous fiber. This chapter compares the processes, structures, and properties of these two classes of fibers. 

Today, the U.S. structural ceramics market is estimated at over 3500 million as compared with 20 million in the year 1974, 350 million in 1990, and 865 million in 1995. The application of these materials can be found in tool manufacturing, automotive, aerospace, electrical, electronics industries, communications (fiber optics), medicine, and so on (http //www.acers.org/news/factsheets.asp). 

Aliphatic polyamides, also known under the generic name nylon. Industrial nylons with the general structure [-RNHCO-] , such as PA-6, PA-11, and PA-12, are called monadic those with the general structure [-NHRiNHCOR2CO-] are called dyadic (PA-4,6, PA-6,6, PA-6,9, PA-6,10, and PA-6,12). Aromatic polyamides or aramids. The best known in the specialty fiber market are Nomex (poly-m-... 

Inorganic fibers which include structural glass, ceramics, boron, and carbon, form a smaller but growing market estimated at 1.8 billion worldwide in 1990.1 11 1 Optical glass, which is a specialized product, is not included. The inorganic fiber market is divided as shown in Table 8.1. 

Carbon fiber introduction into commercial markets happened in the mid-1960s and since then their application has increased substantially. Some of these applications include airplanes, spacecraft parts, compressed gas tanks, automotive parts, bridges, reinforced concrete, structural reinforcement, recreational sports equipment, and electrochemical systems [6,7]. 

DuPont and Shell have developed a new polyester, poly(trimethylene terephthalate) (PTT) (structure 19.38) that is structurally similar to PET, except that 1,3-propanediol (PDO) is used in place of ethylene glycol. The extra carbon in Sorona allows the fiber to be more easily colored giving a textile material that is softer with greater stretch. Further, it offers good wear and stain resistance for carpet use. The ready availability of the monomer PDO is a major consideration with efforts underway to create PDO from the fermentation of sugar through the use of biocatalysts for this conversion. Sorona and Lycra blends have already been successfully marketed. Sorona is also targeted for use as a resin and film. 

Finishing of Wool. Wool (qv) competes for markets where warmth, wrinkle recovery, and ability to set in creases are important. Wool problems relate to shrinkage, particularly to its tendency to felt. This is caused by scaly structure, which tends toward fiber entanglement when wet and subjected to mechanical action. In order to compensate for this tendency, wool needs to be set and also made shrinkproof if it is to be laundered. 

Cyclic oligomeric phosphonates with the varying degrees of structural complexity (Structure 5.4) are also available in the market.25 They are widely used as flame-retardant finishes for polyester fabrics. After the phosphonate is applied from an aqueous solution, the fabric is heated to swell and soften the fibers, thus allowing the phosphonate to be absorbed and strongly held. It is also a useful retardant in polyester resins, polyurethanes, polycarbonates, polyamide-6, and in textile back coatings. A bicyclic pentaerythritol phosphate has been more recently introduced into the market for use in thermosets as well as for polyolefins (preferably, in combination with melamine or ammonium polyphosphate)... 

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