Repeat something remarkable.
Addition polymerisation opens alkene double bonds to join monomers without eliminating a small molecule. Ethene gives polyethene; propene gives a chain with a methyl side group; tetrafluoroethene gives PTFE. Keep all substituents when drawing the repeat unit.
Condensation joins suitable functional groups and eliminates small molecules. Diols plus dicarboxylic acids can form polyesters, and diamines plus dicarboxylic acids can form polyamides. PLA can be described through condensation of lactic acid for this model.
Three amino acids form a tripeptide through two peptide bonds, releasing two waters in the direct condensation model. Read its sequence from the free amino end to the free carboxyl end, such as Gly–Ala–Ser. Monosaccharides join through glycosidic bonds to make disaccharides or polysaccharides.
Join the building blocks
Three ethene units illustrate the polyethene backbone. Dots represent continuation; terminal chemistry is omitted.
Assumed knowledge
A condensation bond forms from complementary functional groups.
Learning checkpoints & source
YOUR SYLLABUS CHECKPOINT- Construct addition and condensation repeat units.
- Name tripeptides in sequence.
- Identify peptide and glycosidic bonds.