An efficient bio-based plasticizer for poly (vinyl chloride) from waste cooking oil and citric acid: Synthesis and evaluation in PVC films

In this study, a bio-based efficient plasticizer (acetylated-fatty acid methyl ester-citric acid ester, AC-FAME -CAE) for poly(vinyl chloride) (PVC) was synthesized by using waste cooking oil and citric acid as raw materials in very user-friendly approaches. Its structure was characterized by FTIR and H-1 NMR. The epoxidation and ring opening reaction were investigated primarily using a GC-MS analysis. Tetrabutylammonium chloride (TBAC) was used as the catalyst of ring opening, and it dramatically accelerated the reaction process of carboxylic acid and epoxy bonds. The glass transition temperature (T-g) decreased to 26.32 degrees C, as determined by dynamic mechanical analysis (DMA), when 50 phr of AC-FAME-CAE was added. The mechanical and migration stabilities of PVC films with AC-FAME-CAE plasticizer were investigated using volatility and extraction tests as well as thermogravimetric analysis (TGA) and TGA FTIR analysis. The mechanical properties of PVC films with AC-FAME-CAE plasticizer were obviously better than those of PVC films plasticized by ESO (epoxidized soybean oil) and as good as those of PVC films plasticized by DOP (dioctyl phthalate, 99%). The structure property analysis of the AC-FAME-CAE as a PVC plasticizer confirmed that a higher molecular weight and more ester bonds could reduce the volatility and extraction loss and improve the compatibility and stability of PVC films. (C) 2018 Published by Elsevier Ltd.