It is a foregone conclusion that more and more plastics will be used in the construction of automobile bodies to reduce weight and make it possible for manufacturers to achieve the much higher fleet average MPG standards mandated by the so-called CAFE regulations. Cars currently use 300-500 pounds of “conventional” plastics (polypropylene, ABS resins, nylon, polyurethane, polycarbonate) in various places (dashboard, bumpers, panels, windshield, etc). To get the dramatic weight reduction required, car bodies will have to be made from so-called structural composites, which are now used for advanced aircraft like Boeing’s Dreamliner.
Structural composites for aircraft and other critical applications are made using carbon fiber (ten times stronger than steel and a quarter of the weight), bonded together with special resins. This type of construction is very expensive and not economically practical for cars, though expensivive automobiles like Ferrari and others do use carbon fiber bodies.
Teijin and GM (see 26 March 2012 issue of The Chemical Daily) recently announced a “breakthrough” process that greatly reduces molding time and, according to the companies, is slated to be used in cars and trucks (no information, however, available on increased car price). But the real breakthrough, will come when carbon fiber with suitable strengh and durability characteristics can be produced from a feedstock other than (expensive) polyacrylonitrile (PAN), the current source of essentially all high stregth carbon fiber. This is the goal of the U.S. Partnership for a New Generation of Vehicles (PNGV). The goal is to produce a carbon fiber for around
$ 3/lb. versus the current cost of $ 8-10/lb. The Composite Materials Technology Group at the Oak Ridge National Laboratory is in partnership with fourteen companies (e.g. Dow, 3M, others) to develop a low cost carbon fiber, a promising candidate being lignin from wood, with others also being evaluated.