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1. READING CRITICALLY (20 minutes)
Read this exerpt carefully again and answer the question: What would life be like without plastic?
Soon chemists began looking for other small molecules that could be strung together to make polymers. In the 1930s, British chemists discovered that the gas ethylene would polymerize under heat and pressure to form a thermoplastic they called polythene.Polypropylene followed in the 1950s. Both were used to make bottles, pipes, and plastic bags. A small change in the starting material replacing a hydrogen atom in ethylene with a chlorine atom-produced PVC (polyvinyl chloride), a hard, fireproof plastic suitable for drains and gutters. And by adding certain chemicals, a soft form of PVC could be produced,suitable as a substitute for rubber in items such as waterproof clothing. A closely related plastic was Teflon, or PTFE (polytetrafluoroethylene). This had a very low coefficient of
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