Accelerating Polyester Melt Polycondensation Through Devolatilization Regulated by Disk Openings in a Horizontal Disk Reactor

ABSTRACT

Prolonged residence at high temperature during melt polycondensation readily induces thermal degradation and etherification side reactions in polyester systems. The reaction time is largely governed by the devolatilization of volatile byproducts generated by the main polycondensation reaction, which is closely related to the apparent volumetric mass transfer coefficient of the reactor. Herein, polyethylene naphthalate (PEN) was used as a representative aromatic polyester to establish a structure‐regulated devolatilization strategy for accelerating melt polycondensation in a horizontal disk reactor. Results show that the four‐opening disk blade achieves the maximum volumetric mass transfer coefficient with an ethylene glycol (EG) removal rate higher than its generation rate, thereby promoting forward equilibrium shift and molecular weight growth during PEN polycondensation. The reactor equipped with four opening blades reaches the target number‐average molecular weight of approximately 20 000 g/mol within 37 min, shortening reaction time by 75.3% relative to the disk without openings while reducing thermal degradation and etherification by 78.3% and 59.3%. This work offers a quantitative basis for blade structure optimization and side reaction control in polyester polycondensation reactors.