PR The Polymer Revolution

PR1 Synopsis

The story of the development of addition polymers, from the first discoveries to the present day, emphasising the chance nature of many of the discoveries. Main topics:

•     what is a polymer?;

•     the discovery of poly(ethene) and the properties of thermoplastics;

•     different kinds of poly(ethene);

•     conducting and light-emitting polymers;

•       dissolving polymers.

PR2 Learning outcomes

Candidates should be able to:

(a)     show awareness of the historical development of addition polymers: discovery of poly(ethene), different kinds of poly(ethene), Ziegler-Natta catalysts, conducting and light-emitting polymers, dissolving polymers;

(b)     show awareness that scientific discoveries are often made by accident and give some     examples of polymers discovered in this way;

(c)     explain and use the term: addition polymerisation;

(d)     predict the structural formula of the addition polymer formed from given monomer(s), and    vice versa;

(e)     use systematic nomenclature to name alkenes;

(f)       recognise cis-trans (geometric) isomers;

(g)    build models and draw and interpret diagrams to represent cis-trans isomers.

(h)     describe and explain the addition reactions of alkenes with the following:

(i)         bromine,

(ii)         hydrogen bromide,

(iii)        hydrogen in the presence of a catalyst,

(iv)        water in the presence of a catalyst;

(i)       explain and use the terms: addition, electrophile;

(j)       explain the mechanism of the electrophilic addition reaction between bromine and

      alkenes;

(k)     decide whether a molecule is polar or non-polar from its shape and the polarity of its bonds;

(l)   describe and exemplify the following types of intermolecular forces:

(i)         instantaneous dipole - induced dipole attractions,

(ii)         permanent dipole - permanent dipole attractions,

(iii)                hydrogen bonding;

      (m)             describe and explain the principal features of the molecular structure of water:

(i)         bonding and shape of the water molecule,

(ii)                 hydrogen bonding in water and ice;

       (n) explain the properties of addition polymers and other substances in terms

      of  intermolecular attractions;

(o)  explain the meaning of the terms: thermoplastic and thermoset, co-polymer;

(p)     describe the meaning and significance of crystallinity in polymers;

(q) relate the typical properties of addition polymers to their molecular structure, and make predictions about the properties of a given polymer. In particular, the following factors should be considered

(i)         chain length,

(ii)         side-groups,

(iii)        chain branching,

(iv)        chain flexibility,

(v)         cross-linking,

(vi)                stereoregularity;  

(r) relate the properties of a dissolving polymer to its molecular structure;

(s)   distinguish between primary, secondary and tertiary alcohols from their structures;

(t)      recognise members of the following homologous series: aldehydes, ketones, carboxylic acids;

(u)describe and explain the following properties of alcohols:

(i)   oxidation of alcohols to carbonyl compounds and carboxylic acids with acidified dichromate(VI) solution;

(ii)  dehydration of alcohols to form alkenes;

      (v)     explain and use the term: elimination reaction.