Synthesis and evaluation of dioctyl 2,5‐thiophenedicarboxylate as a potentially bio‐based plasticizer for poly(vinyl chloride)

Abstract

AbstractIn this work, dioctyl 2,5‐thiophenedicarboxylate (DOT), a potentially bio‐based plasticizer, was synthesized and evaluated as an alternative to traditional petroleum‐based plasticizers. The chemical structure of DOT was confirmed by FTIR and 1H NMR. Besides, its plasticization effect on poly(vinyl chloride) (PVC) was investigated in detail, and dioctyl 2,5‐furandicarboxylate (DOF) as well as dioctyl isophthalate (DOIP) with similar chemical structures were used as references. The DMA results showed that the glass transition temperature (Tg) of PVC/DOT, PVC/DOF, and PVC/DOIP was 45.1°C, 33.6°C, and 51.3°C, respectively, indicating that the plasticizing efficiency of DOT was better than that of DOIP but lower than that of DOF. However, the tensile test results exhibited that the elongation at the break of PVC/DOT was higher than that of PVC/DOF, which was attributed to the easy phase separation between DOF and PVC. In addition, DOT displayed the best volatility resistance and exudation resistance among the three plasticizers, attributed to its highest molecular weight. Moreover, the migration loss of DOT in non‐polar solvents was much smaller than that of DOIP because of its stronger molecular polarity. In conclusion, DOT has good potential to replace traditional petroleum‐based plasticizers and be used as a primary plasticizer for PVC.