Plasticization and thermal behavior of hydroxyl and nitrogen rich group-containing tung-oil-based ester plasticizers for PVC

Hydroxyl and nitrogen rich group-containing tung-oil-based ester (GEHTMA-1, GEHTMA-2, GEHTMA-3 and GEHTMA-4) plasticizers were successfully synthesized from tung-maleic anhydride and utilized to plasticize poly(vinyl chloride) (PVC). In comparison to petroleum-based plasticizers (e.g. DOTP), the mechanical test shows that bio-based GEHTMA-3 displays better mechanical properties, which means that GEHTMA-3 could endow PVC resins with well-balanced properties of flexibility and strength. With the addition of GEHTMA-3 into DOTP, PVC/DOTP/GEHTMA-3 exhibits better mechanical properties, plasticization performance, migration resistance and thermal stability compared with the PVC/DOTP system. Above all, PVC/28DOTP/12GEHTMA-3 shows the highest tensile strength and elongation of 32.19 MPa and 345.20%, respectively. PVC/32DOTP/8GEHTMA-3 displays the best thermal stability. The superior performance is attributed to the molecular interaction of GEHTMA-3 and DOTP with PVC. The interaction originates from the simultaneous introduction of hydroxyl, epoxy, benzene ring, ester and nitrogen rich groups into GEHTMA-3 structures. Besides, GEHTMA-3 presented good miscibility with PVC resins, particularly when a mixture of DOTP and GEHTMA-3 was used. In addition, possible plasticization of the PVC/DOTP/GEHTMA-3 system was presented.