Chemistry – Organic chemistry - Polymers | e-Consult

A typical condensation polymer consists of long chains made up of repeating units derived from the monomers that condensed to form it. These repeating units are linked together by covalent bonds that were formed during the condensation reaction. The repeating units are essentially the monomers with the small molecule (e.g., water) removed.

The properties of a condensation polymer are significantly affected by the type of functional group involved in the condensation reaction. Here's a breakdown:

• Polyesters (e.g., PET): Formed from the reaction of a dicarboxylic acid and a diol. The ester linkage (-COO-) is relatively strong and resistant to hydrolysis. This makes polyesters strong and durable, suitable for clothing and bottles. However, they are not biodegradable.
• Polyamides (e.g., Nylon): Formed from the reaction of a dicarboxylic acid and a diamine. The amide linkage (-CONH-) is also strong and relatively resistant to hydrolysis. Nylon is known for its high tensile strength and elasticity, making it suitable for textiles and ropes.
• Starch: Formed from the condensation of glucose molecules. The glycosidic linkages (-O- between carbons) are susceptible to hydrolysis by enzymes and acids. This makes starch a good source of energy for plants and a readily digestible carbohydrate for animals.
• Protein: Formed from the condensation of amino acids. The peptide bonds (-CONH-) are strong and relatively resistant to hydrolysis. The specific sequence of amino acids determines the protein's structure and function.

The strength of the bonds between the repeating units, the polarity of the functional groups, and the ability of the polymer chains to form intermolecular forces (e.g., hydrogen bonding) all contribute to the overall properties of the condensation polymer.