Statistical Process Optimization of Functionalized PET Oligomer Nanocomposites from Off-Grade PET

Abstract

Off-grade Poly(ethylene terephthalate) (PET) of industrial manufacturers was partially depolymerized, using excess ethylene glycol (EG) in the presence of manganese acetate to synthesize PET oligomers. Influences of EG/PET molar ratio, reaction time, and catalyst concentrations and particle size of off-grade PET on yield of partial glycolysis reaction were investigated. The optimal conditions to synthesize PET oligomer (melting point of about 180°C) were obtained. Then, maleated PET as a compatibilizer for preparing PET nanocomposites was produced via reaction between maleic anhydride/phthalic anhydride (MA/PhA) composition and optimized PET oligomers. The combination of reaction time of 106 minutes and PhA/MA molar ratio of 0.85 gave the best results based on d-spacing and peak shift of nanocomposite samples. Hence, melt mixing of maleated PET with organoclay produced a good intercalation of layered silicate and good dispersion of clay in maleated PET matrix. Analysis of variance (ANOVA) was studied for both glycolyzed products and functionalized PET oligomers.