The depolymerization of waste poly(ethylene terephthalate) (PETW) flakes from bottles was investigated using a nonaqueous NaOH in ethylene glycol solution and was carried out at p atm from 150 to 185 °C, using a NaOH:PET molar ratio of 4:1. The increasing amount of water taken up by the flakes and after submitting them to thermopressing at 260 °C increased the reactivity of the rectangular specimens thermopressed during the depolymerization. At a stirring rate value of 1360 rpm, the product was removed from the unreacted PET surface and the chemical reaction was rate-determining. Using the kinetic model of shrinking core of heterogeneous chemical reaction control, considering the formation and growth of cracks and pores on the polymer surface, the E a value was 172.7 kJ·mol -1, which was relatively high. However, in the thermodynamic analysis it was shown that the compensation effect of the Δ S ⧧ over the Δ H ⧧ is sufficiently high to compensate for the high E a .
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Rúvolo‐Filho et al. (2006) studied this question.
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