Building Materials, Third Edition

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It may be defined as a reaction that yields a product which is an exact multiple of the original
monomeric molecule. Such a monomeric molecule usually contains one or more double bonds,
which by intermolecular rearrangement may make the molecule bi-functional.
Fig. 16.4 (a) shows ethylene polymerisation. One of its double bond is transferred to form a
bond with the adjacent monomer and the resultant product is polyethylene which serves the
prototype for addition polymerisation. It is commonly used in the manufacture of flexible films
and squeeze bottles. Some of the other examples are shown in Fig. 16.4 (b,c).