Transcript Energy4.ppt
I. ENERGY AND TRANSPORTATION I.5. Automotive vehicles Advanced materials for design, comfort, and safety The automobile of 21st century bears little resemblance to its early predecessors in design, comfort, and safety for passengers. High-intensity discharge headlamps allow maximum nighttime illumination. Corrosion has been drastically reduced by special coatings and materials. Chemical refrigerants circulate in a closed-environment system. Automotive safety glass was introduced in 1914. Today, special polymers coat glass to reduce weight and outside noise and to protect from glare and ultraviolet radiation. Safety innovations include polymer fibers in seat belts (required in the 1960s) and in air bags (required in 1996). Plastic components Reducing the weight of automobiles by transitioning from metal to plastics and identifying new high-performance materials is made possible by chemical achievements. After World War II., automobile manufacturers began using synthetic petroleum-based polymers for rigid structural components because of their toughness, hardness, and weather resistance. After the 1970s energy crisis, lightweight alternatives were sought for metals in order to improve fuel efficiency. Design applications include: complex body shapes fabricated by injection molding, thermoplastic bumpers, polypropylene fibers that are colorfast and UV-stable, and special paints, coatings, and adhesives. Polypropilene fibers Tire technology Natural rubber products appeared in the early 1800s, but were impractical due to softening or brittleness in hot or cold weather. An American inventor Charles Goodyear developed the vulcanization process for natural rubber in 1839, linking unsaturated bonds with sulfur. This basic process is still used with additional chemical accelerants and stabilizers. By 1945, synthetic rubber was being produced commercially. As tire demand increased, other improvements were introduced, including an inner tube to replace solid rubber tires, reinforcement with natural or synthetic fabric cord for strength, added materials for reduced wear, and the eventual debut of tubeless tires.