Upcycling poly(ethylene terephthalate) wastes by solvent extraction: Thermal stability and kinetics studies of the recovered PET

Abstract

Everyone who drinks bottled water contributes at least 17 kg to the post‐consumer poly(ethylene terephthalate) (W‐PET) accelerating the accumulation of the waste plastics (WP) that already have an annual rate of increase of ~4.5%. Disposals of W‐PET mimics a pseudo‐renewable resource of WP, that creates many recycling and economic opportunities. This work presents a recycling method that reduces the burden of W‐PET on the environment while saves energy and creates new economic opportunities. The recovered purified PET (PET‐R) that its thermal properties are reported here was obtained by solvent extraction method. Five samples of PET‐R were analyzed by thermogravimetry to study its kinetics properties assuming that the degradation process followed a pseudo‐single component model. The isoconversional Ea,α values obtained from the f(α) functions were comparable to each other by the average and standard deviation of 200 ± 5 kJ mol−1; which is very close to the value of Ea of pure PET. The results were consistent with kinetics data reported in the literature for pure PET.

Upcycling poly(vinyl chloride) waste tubes: Studies of thermal stability and kinetics of films made of waste polyvinylchloride tube at the initial steps of degradation

“…As the reaction progressed the E a,α of wPVCf followed different paths according to the nature of the reaction and reactants as shown by the graphs in Figure 9. The values of E a,α of wPVCf were closed to each other as shown graphically in Figure 9a and the values listed in Table 5; similar behavior was reported by other researchers 18,36,42 . The decomposition of PVC consisted of two steps, first step dehydrochlorination, and then decomposition of newly formed materials including polyenes.…”

“…The values of E a,α of wPVCf were closed to each other as shown graphically in Figure 9a and the values listed in Table 5; similar behavior was reported by other researchers. 18,36,42 The decomposition of PVC consisted of two steps, first step dehydrochlorination, and then decomposition of newly formed materials including polyenes. The values of E a barrier for the removal of HCl is expected to be constant and independent of the chain length at the initial steps of the reaction.…”

“…The negative values of E a result from combinations of a number of exothermic and endothermic reactions where the net value of the energy barrier becomes negative as has been reported for others thermal degradation reactions. 41,42…”