Polymers on the move

The oil price shock of the 1970s led to the first big increase in the use of plastics in transport. Metal bumpers, wooden dashboards, leather-covered steel steering wheels, and glass headlamp covers were soon replaced by plastics, such as ABS - acrylonitrile (2-propenenitrile) butadiene styrene - a tough plastic made by polymerising 2-propenenitrile and styrene (phenylethene) in a preformed latex of polybutadiene rubber.  

Windscreens used to sit loosely in rubber surrounds until chemists discovered that bonding them in place with polyurethane adhesives meant that the strength of glass could contribute to the roll-over strength of a car, so that there was room to reduce the body weight. The rubberised hair in seat cushions was replaced with polyurethane foam (see Box 1), and new applications for plastics and elastomers appeared such as cup holders and sound insulation foam under the bonnet.  

Not all were inspired by the desire to reduce the weight of the vehicles - often lower cost or greater design flexibility were more important - but the overall effect was improved fuel efficiency. By 1977 plastics contributed 4.6 per cent of the average weight of a vehicle.¹