Addition Polymerisation Flashcards

All 7 cards in this deck

What is addition polymerisation?

Many small molecules (monomers) join together to form very large molecules (polymers), with the polymer as the only product.

Which functional group must a monomer contain to form an addition polymer?

A C=C double bond (the monomer is an alkene).

Why does the repeating unit of an addition polymer contain the same atoms as the monomer?

Because no other molecule is formed in the reaction — every atom of the monomer ends up in the polymer.

What are the steps to draw the equation for the formation of an addition polymer from an alkene monomer?

e.g. ethene $\mathrm{CH_2{=}CH_2}$

1. Write $n$ in front of the monomer's displayed formula: $n$ ethene with C=C.
2. Change C=C to a single C–C bond and extend a bond from each end carbon through the brackets.
3. Write $n$ after the bracket: poly(ethene) repeating unit $\mathrm{-CH_2-CH_2-}$.

What are the steps to deduce the monomer from a given repeating unit of an addition polymer?

e.g. repeating unit $\mathrm{-CH_2-CHCl-}$

1. Take one repeating unit from inside the brackets.
2. Remove the two bonds that pass through the brackets.
3. Change the C–C bond in the backbone to C=C: monomer is chloroethene $\mathrm{CH_2{=}CHCl}$.

True or false? In addition polymerisation a small molecule such as water is lost as the monomers join.

False. No other molecule is formed — the polymer is the only product.

True or false? The repeating unit of an addition polymer is drawn with a C=C double bond, just like the monomer.

False. The double bond opens up during polymerisation, so the repeating unit is drawn with single C–C bonds and two bonds extending through the brackets.