Teflon. This essay will discuss the uses of Teflon, and the myths and truths surrounding it.

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STAGE 2 CHEMISTRY     SOCIAL & ENVIRONMENTAL RELEVANCE TASK 2

CORNERSTONE COLLEGE

Name: NATALIE BAMPTON                               Topic: TEFLON

INTRODUCTION:

Teflon is also known as polytetrafluoroethylene and can be found in cookware, electronics, aeronautics and clothing. It was invented by accident by Roy Plunkett, who was originally supposed to invent a CFC gas refrigerant for the company DuPont™. He was investigating a substance called TFE as an alternative to toxic refrigerants such as ammonia and sulphur dioxide. Since TFE is expensive, he froze it to keep it safe. While experimenting one day, he tried to empty one of the supposedly full canisters of TFE, when nothing came out. He opened the canister to find the TFE had polymerised into a white powder, because of the high pressure and low temperature. The waxy substance was Teflon; it was slippery, non-corrosive and chemically stable, which was a breakthrough for DuPont™ and the rest of the world. However, recent studies have shown that Teflon may be toxic or is even likely to cause cancer. This essay will discuss the uses of Teflon, and the myths and truths surrounding it.

CHEMISTRY:

Polytetrafluoroethylene is a long chain of tetrafluroethylene monomers bonded to each other. It is a carbon chain backbone with two fluorine atoms attached to it. In a monomer tetrafluroethylene unit, a carbon is double bonded to another carbon, and then bonded to two fluorine atoms as show in the diagram below. In order for these monomer units to become polytetrafluoroethylene or PTFE, they must undergo polymerisation in which the carbon to carbon double bond is broken to form a chain. This happens in three steps: the initiation, propagation and termination. The initiation stage happens when the initiator molecule (in this case the tetrafluroethylene molecule) breaks apart, to leave two unbonded electrons free. These molecules are also known as free radicals, and are highly reactive. In the propagation stage, the initiation stage happens as a chain reaction chain reaction and is repeated many times over and over again, allowing tetrafluroethylene to be continually added to the mixture. There are two main kinds of termination reactions, coupling and disproportionation. In the                                       coupling reaction, the two unpaired electrons on the carbon atoms bond to others                               naturally, causing a chain to form, as shown in the diagram below.

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In disproportionation, termination occurs in which a carbon atom, instead of bonding with another carbon, bonds with a fluorine atom, hence having three fluorine atoms attached to it and terminating the chain. The product of this polymerisation is polytetrafluoroethylene polymer.

This polymer is most famous for its slipperiness. This is because of the fundamental part of this molecule: the fluorine atoms. Fluorine is the most electronegative atom of all, and within this structure, it is bonded to carbon which has a relatively low electronegativity. When fluorine is within a molecule, it does not react with other molecules ...

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