Polyesters are "Alcohol + Acid". Polyamides are "Amine + Acid". Phenol-Formaldehyde resins (like Novolac and Bakelite) use formaldehyde as the linking agent, creating ether or methylene bridges.
Step 1: Understanding the Concept:
Polymers are classified by the nature of the repeating functional group (linkage) in their backbone. Polyesters contain ester (\(-\text{COO}-\)) linkages formed by the condensation of polyhydric alcohols and polycarboxylic acids. Step 2: Detailed Explanation: 1. Glyptal: Formed by the condensation polymerization of ethylene glycol and phthalic acid. It contains ester linkages. Hence, it is a polyester. 2. Dacron (Terylene): Formed by the condensation of ethylene glycol and terephthalic acid. It is a well-known polyester fiber. 3. PHBV: Poly(\(\beta\)-hydroxybutyrate-co-\(\beta\)-hydroxyvalerate) is a copolymer of 3-hydroxybutanoic acid and 3-hydroxypentanoic acid. It contains ester linkages and is a biodegradable polyester. 4. Novolac: It is a linear polymer formed by the condensation of phenol and formaldehyde in an acidic medium. The monomeric units are linked by methylene (\(-\text{CH}_2-\)) bridges, not ester bonds. It is a precursor to Bakelite and belongs to the class of phenol-formaldehyde resins. Step 3: Final Answer:
Novolac is not a polyester.
