Polycondensation Kinetics and Thermodynamics
topic
Polycondensation of BHET at 270–285°C under high vacuum (<1 mmHg) with antimony trioxide catalyst removes ethylene glycol, building molecular weight. Degree of polymerisation follows second-order kinetics; equilibrium constant Kp determines achievable DP. Side reactions include thermal degradation, diethylene glycol (DEG) formation, and acetaldehyde generation.
Role
Kinetic and thermodynamic control of polycondensation determines final MW distribution, DEG content, carboxyl end-group concentration, and colour index of the polymer — all directly impacting fibre quality.