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Polymeric materials are being used in increasing amounts on the exterior of automobiles because of weight reduction, corrosion resistance, design flexibility, and cost effectiveness. A variety of applications, including fascia, bumper covers, cladding, and rocker panels, require materials with a demanding and broad range of properties. In this paper, the needs of these automotive application areas and advancements in the thermoplastic elastomer based technology to satisfy these needs are described.

Plastics have an important niche in glazing applications where there is concern over vandalism and breakage, maintenance and repair, weight and design, and rolled up costs over the life of the article. Glazing undergoes attack by impinging solids, liquids, gases and radiation. Tests are presented which are useful in evaluating resistance of plastics to attack, both initially and after weathering. The development history of a new resistant coating for poly(methyl methacrylate) is sketched, and complete performance data are included. Coated acrylic offers an unusually good balance of properties for transportation and architectural uses.

The increasing use of plastics as strong, load-bearing materials in industry has raised certain questions about the standard tests used to describe their performance. Even after all of these tests have been run, there are still several unanswered questions. How will the fabricated part stand up under impacts in service? What kind of melt flow can be expected in the normal injection molding process? Will increasing glass content improve stress crack resistance? What is the effect of fiber orientation on material properties? These are the questions that this paper attempts to deal with in terms of “Alathon”* glass-fiber reinforced, high density polyethylene. Because they represent difficult areas of interpretation, they are in need of more attention. Other standard test results on Du Pont’s family of glass-reinforced, high density polyethylene resins are also presented.

Plastic fiber optics have been developed which possess excellent light transmission characteristics. The basic theory which explains this phenomenon of light transmission through plastic fibers and certain physical properties which characterize the utility of Crofon plastic fiber optics are discussed. Particular emphasis is placed on optical properties. In addition, mention is made of plastic fiber end finishing techniques, accessory fittings, and applications.

USE of a motored engine as a convenient method for studying precombution reactions is described in this paper. Preliminary investigations of this technique were made in 1950, and this paper covers the work accomplished since then in establishing a better understanding of chemical reactions preceding knock. Extent and type of precombustion reactions which occur in the unburned charge ahead of the flame front determine the tendency of a fuel-air mixture to knock. Use of a motored engine substitutes compression of the unburned charge by the piston for compression of the end gas by the flame front. The buildup of knock-producing materials is considered in studies of mixture compositions and time factors. Observed precombustion reactions are related to problems concerning the adaptation of fuels to engines.