فهرست نشریات علمی دسترسی آزاد ایران

Conventional polyvinyl chloride (PVC) recycling processes require high temperatures (>400 °C), leading to excessive energy use and hazardous emissions. This study explores ambient-condition and low-temperature approaches utilizing imidazolium-based ionic liquids (ILs)—1-methylimidazole, 1-ethyl-3-methylimidazolium acetate (EMIM OAc), and 1-butyl-3-methylimidazolium chloride (BMIM Cl)—as pretreatment media for PVC plastic wrap. PVC films were contacted with aqueous IL solutions at a 1:1 mass ratio and stirred for 24 h at 25 °C, followed by treatment at 110 °C for 8 h. Raman spectroscopy characterized the PVC phase, while FTIR analyzed IL-rich fractions. At ambient conditions, 1-methylimidazole initiated the onset of dehydrochlorination, evidenced by attenuation of CH₂ deformation bands (~1,430–1,450 cm⁻¹) and appearance of polyene signals (~1,500–1,520 cm⁻¹). In contrast, EMIM OAc and BMIM Cl exhibited stronger C–H stretching and spatially heterogeneous responses between 11,00 and 15,20 cm⁻¹, suggesting dominant plasticization and interfacial rearrangement. At 110 °C, EMIM OAc promoted pronounced dehydrochlorination with diminished C–Cl intensity (500–700 cm⁻¹), enhanced conjugated C=C bands (1,500–1,610 cm⁻¹), and an increased Ipolyene/Ibackbone ratio. BMIM Cl primarily reduced C–H stretching near 2,900–2,930 cm⁻¹ and moderately increased polyene features, implying limited C–Cl scission. FTIR spectra confirmed IL structural integrity, revealing only the disappearance of broad O–H/N–H bands due to moisture loss without signs of degradation. These results demonstrate that imidazolium-based ionic liquids can promote PVC dehydrochlorination and polyene formation at substantially lower temperatures, offering a stable and recyclable route for sustainable PVC recycling.