Polymerisation

Individual monomer units (small molecules)

Polymer (long-chain molecules)

In the production of polythene the small molecular units of ethylene are joined end to end by an additional polymerisation process to produce the long-chain macromolecules. A similar process converts vinyl chloride into polyvinyl chloride (PVC) (Fig. 10.2), styrene monomer into polystyrene and tetrafluoroeth-ylene into polytetrafluoroethylene (PTFE).

While the molecular backbones of plastics are predominantly composed of chains of carbon atoms, variations occur, particularly when the polymerisation

Ethylene (gas) Polyethylene (polythene)

Fig. 10.1 Polymerisation of ethylene to polyethylene (polythene)

Fig. 10.2 Polymerisation of vinyl chloride to PVC

Elimination of water |j between adjacent monomer units

Fig. 10.3 Condensation polymerisation

Condensation polymerisation

■C — OH —-<Y-0 — C—Q-C—0-<Y-0 — C—Q-C—0—0~ II v II Il v II II

Polyester process involves the elimination of water between adjacent monomer units. Thus in the case of condensation polymerisation (Fig. 10.3), oxygen or nitrogen atoms are incorporated into the backbone of the macromolecular chains as in the polyesters (resins) and polyamides (nylons).

Was this article helpful?

0 0
Oplan Termites

Oplan Termites

You Might Start Missing Your Termites After Kickin'em Out. After All, They Have Been Your Roommates For Quite A While. Enraged With How The Termites Have Eaten Up Your Antique Furniture? Can't Wait To Have Them Exterminated Completely From The Face Of The Earth? Fret Not. We Will Tell You How To Get Rid Of Them From Your House At Least. If Not From The Face The Earth.

Get My Free Ebook


Post a comment