The effect of seawater aging on the pyrolysis of fishing nets

Abstract This study examined the effects of seawater aging on the physicochemical properties and pyrolysis behavior of nylon-6 (N6) and polyethylene (PE) using Fourier transform infrared (FT-IR) spectroscopy, X-ray fluorescence spectroscopy, thermogravimetric analysis (TGA), and pyrolyzer-gas chromatography/mass spectrometry (Py-GC/MS). The analyses revealed an increase in the contents of fixed carbon and ash in both N6 and PE due to aging in seawater for five months. FT-IR spectroscopy indicated an increase in the content of the hydroxyl group in the structures of both aged N6 and PE, suggesting their partial decomposition and oxidation during seawater aging. TGA showed that the maximum decomposition temperature (Tmax) and pyrolysis kinetic parameters of N6, such as the activation energy and pre-exponential factor, were changed by seawater aging. Although the Tmax of PE did not change significantly with seawater aging, the differential thermogravimetric peak shape and kinetic parameters of PE were changed by seawater aging. The isothermal Py-GC/MS results at 600 °C showed that aged N6 produced 3-amino-pentanol in addition to the typical pyrolyzates of fresh N6. Furthermore, the pyrogram of aged PE was similar to that of fresh PE.