Polycondensation

For years, the polymer chemistry community widely employed the terms “step-growth” and “chain growth” to classify polymers, supported by the mechanism involved during the formation of the polymer chain. Condensative chain polymerization starts when an active molecule reacts with a monomer through a condensation reaction and generates a molecule that is inactive to grow a polymer chain until it eliminates a small molecule. Kinetically controlled polycondensation is present when highly reactive functional groups interact, the equilibrium is fully displaced to the right, and these reactions are considered irreversible, leading to high degrees of polymerization. In linear polycondensation, the achievement of average degrees of polymerization higher than 50 implies the reaction with high-purity monomers, balanced stoichiometric ratios, and conversions higher than 98%. The main aim of polycondensation kinetics is the prediction of the polymerization rate, structural polymer properties, and functional end-group concentration.