Abstract: The illegal cooking oil was processed through esterification,followed by acid-catalyzed epoxidizing,and the product,epoxy fatty methyl ester,was used as a plasticizer of PVC.The structure of the product and the raw material was determined. A weak absorption peak at 839.2cm-1 was observed on FTIR Spectroscopy, which indicated the generation of epoxy groups. The composition of illegal cooking oil determined by GC-MS revealed that the content of unsaturated fatty methyl ester was decreased obviously whilst the epoxy fatty methyl ester was increased slowly with increasing epoxidizing time.After 8h of epoxidizing ,an epoxid value of 3.9% was observed and the iodine value decreased from 87.7 to 8.7.The epoxy fatty methyl ester had a high flashing point (197℃)and showed similar plasticizing efficiency as DOP. A 50wt% ester could decrease the glass transition temperature of PVC from 87℃ to -10℃.The migration resistance of epoxy fatty methyl ester was inferior to DOP.

Key words: illegal cooking oil, epoxy fatty acid methyl ester, poly(vinyl chloride), plasticizer