The Influence of Specific Surface Area on the Glycolysis Mechanism of <scp>PET</scp> Fibers

ABSTRACT Efficient glycolytic depolymerization of waste polyethylene terephthalate (PET) is critical for sustainable resource recycling, yet the effect of specific surface area—a key structural parameter of PET fibers—on reaction kinetics and depolymerization mechanisms remains unclear. In this work, PET fibers with uniform crystallinity (~27%) and varying specific surface areas (0.640, 0.520, 0.307 m 2 g −1 ) were prepared, and their glycolytic behavior was investigated at 165°C–180°C using zinc acetate as catalyst. Scanning electron microscopy confirmed an outside‐in depolymerization mode with oligomeric fragments detaching from fiber surfaces. Conversion curves were well‐fitted by the Avrami–Erofeev model with n = 2, corresponding to one‐dimensional heterogeneous nucleation and growth of depolymerization domains along fiber longitudinal direction. Apparent activation energies increased with decreasing specific surface area (136.8, 162.9, 172.9 kJ mol −1 , respectively). This work elucidates the structure–activity relationship of PET fibers in glycolysis, providing theoretical guidance for low‐energy, high‐efficiency waste PET recycling.