The 2000 Mustang SVT Cobra R went into production in early spring with carbon-fiber air ducts that cool the front brake rotors.
The Ford Equator concept truck features bumpers, fenders, wheel wells, and lower trim panels made of Kevlar.
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The term "plastics" encompasses organic materials (carbon, hydrogen, nitrogen, etc.) of large molecular weight that can be shaped by flow. The term usually refers to the final product, with fillers, plasticizers, pigments, and stabilizers included, versus the resin-the homogeneous polymeric starting material. Plastics are polymers, which are created by the chemical bonding of many identical or related structural units.
Polymers that contain primarily carbon and hydrogen are classified as organic polymers, including polypropylene (PP), polybutylene (PB), and polystyrene (PS). Other elements found in the molecular makeup of polymers include oxygen, chlorine, fluorine, nitrogen, silicon, phosphorous, and sulfur. Polyvinyl chloride (PVC) contains chlorine. Nylon contains nitrogen. Teflon contains fluorine. Polyester and polycarbonates (PCs) contain oxygen. Polymers that have a silicon or phosphorous backbone, instead of a carbon one, are considered inorganic polymers.
A thermoplastic is a polymer in which the molecules are held together by weak secondary bonding forces that can be softened and melted by heat, then shaped or formed before being allowed to "freeze" again. The heating and cooling processes can be repeated many times without significant chemical change. A thermoset is a polymer that solidifies irreversibly when heated due to a chemical reaction involving cross-linking between chains. Thermoplastics in general exhibit better flexural and impact performance and superior resistance to solvents; thermosets tend to have better compressive strength and abrasion resistance and significantly better dimensional stability.
Composites consist of a reinforcing fiber in a polymer matrix. Polyester, vinyl ester, and epoxy resins are most often the matrix of choice. Composites essentially combine the strength and rigidity of metals and the light weight, flexibility, and corrosion resistance of plastics. Henry Ford began experimenting with composites around 1940, initially using compressed soybeans to produce composite plastic-like components. As can be seen in the lead photo from 1941, the phenolic trunk lid was strong enough to withstand an energetic Ford armed with a sledgehammer.
According to the Composites Fabricators Association, about 65% of all composites produced currently use glass fiber and polyester or vinyl ester resins, and are manufactured using an open molding method. The remaining 35% are produced with high-volume manufacturing methods or use advanced materials, such as carbon or aramid (polyamides such as Kevlar) fiber. Carbon fiber is primarily in use in the motorsports and aerospace industries because of its significant strength and frictional performance. The main reason for its limited use in the automotive industry has been its high cost, though one recent use is in Ford's 2000 SVT Mustang Cobra R. Air inlets designed into the Cobra R's fog light bezels are used to provide extra cooling for the front brakes. Air ducts run from these inlets to special carbon-fiber heat shields fitted around the inside of the brakes to intercool the rotors. The heat shields were developed by Multimatic Motorsports and were used by 1999 Cobras in the Motorola Cup racing series. The main automotive application for carbon fiber continues to be for moving parts in the engine and transmission.
Aramid fibers are used in moving parts where lubricity and dimensional consistency are more important than strength or rigidity, such as clutch belts and grease-free ignition switches. However, the Ford Equator concept truck displayed at the North American International Auto Show (NAIAS) in January featured Kevlar bumpers, fenders, wheel wells, and lower trim panels, making the parts resistant to stone damage and what Ford confidently described as "nearly indestructible."
Polymers have very distinct characteristics, but all have things in common. They are resistant to harsh chemicals; provide both thermal and electrical insulation; offer good noise, vibration, and harshness (NVH) characteristics; offer design flexibility; have an excellent strength to mass ratio; and offer a variety of production options. They can be molded into the body of a car, or mixed with solvents to become an adhesive or paint. Elastomers and some plastics are very flexible. Other polymers can be foamed, like PS and urethane. Polymers seem to have an unlimited range of characteristics and colors, with inherent properties that can be enhanced by a wide range of additives to broaden their uses.
