Alkyd resins synthesized from glycolysis products of waste PET

Abstract

Waste polyethylene tereplithalate (PET) flakes were depolymerized by using ethylene glycol (EG) in the presence of zinc acetate as catalyst. Glycolysis reaction products of waste PET obtained by using PET/EG molar ratios 1/2, 1/4, and 1/6 were extracted three times with boiling water. Solid fraction was named water-insoluble fraction (WIF). The filtrate was cooled to 4 degrees C and the crystallized solid obtained by filtration was named water-soluble crystallizable fraction (WSCF). All of the products were reacted with phthalic anhydride (PA), penthaerythritol (PE), and fatty acid (FA) (iodine value 155, acid value 195) to get alkyd resins. The reactions were followed with acid value. The physical and chemical properties such as drying time, hardness, abrasion resistance, water AA resistance, alkaline resistance, and thermal oxidative degradation resistance (with thermogravimetric analysis, TGA) of these resins were investigated. The waste PET resins were compared with the reference resin prepared with PA, PE, FA, and EG. The properties of the waste PET-based resins were found to be compatible with the properties of the reference resin.