question_answer

  What are polymers? How are polymers classified on the basis of structure?                                         [3]

Answer:

  A polymer is a large molecule made by linkino together repeating units of small molecules called monomers. The process of linking them up is called polymerisation.         [1]

	Type	Characteristic	Example
(i)	Linear polymers	Have long and straight chains, have high density	Polythene, polyvinyl chloride (PVC) [1]
(ii)	Branched chain polymers	Have linear chains with some branches, have low density	[1]
(iii)	Cross-linked or Network polymers	Formed from monomers with two and three functional groups; have strong covelent bonds	Bakelite melamine