Design and synthesis of ethoxylated esters derived from waste frying oil as anti-ultraviolet and efficient primary plasticizers for poly(vinyl chloride)

In this work, a series of novel bio-based plasticizers, including ethoxylated esters, methylated esters, and glycidyl esters, originated from waste frying oil (WFO), were prepared, characterized, and used as primary plasticizers for Poly (vinyl chloride) (PVC). The glass transition temperature, mechanical properties, transparency, UV resistance, thermal stability and migration resistance of plasticized PVC were investigated and compared with that of the PVC sample plasticized by the commercial dioctyl terephthalate (DOTP). It is found that all of those properties are significantly depended on the structures of ester groups. In particular, the esters bearing ethyoxyl units show better plasticization than that having methyl or glycidyl groups. In addition, the plasticizing efficiencies of WFO-derived ethoxylated esters are proportional to the number of ethyoxyl units in their structures. Among them, the anti-ultraviolet PVC sample plasticized by WFO-derived polyacid (triethylene glycol monomethyl ether) esters (WFOPA-3, “3” refers to the number of ethylene glycerol units in the feedstock of triethylene glycol monomethyl ether) with maximum ethyoxyl units exhibited the best plasticization, thermal stability, and transparency than the properties of other samples plasticized by WFO-based plasticizers, as well as petro-based DOTP. The results suggest WFOPA-3 is an attractive potential as alternative to DOTP.