Effect of ketal group in castor oil acid-based plasticizer on the properties of poly(vinyl chloride)

摘要

Two castor oil acid esters containing a ketal or ketone group (KCL or CL), as alternative plasticizers for poly(vinyl chloride) (PVC), were prepared. The structures were confirmed by H-1 NMR and FTIR spectroscopies. The effects of the presence of a ketal or ketone group in these compounds on PVC plasticization were examined. The DMA and SEM results showed that both plasticizers were miscible with PVC and exhibited excellent plasticizing properties, compared to those of dioctyl phthalate (DOP). The PVC plasticized by KCL displayed a lower T-g value of 20.6 degrees C, which was lower than that of PVC plasticized with DOP (22.3 degrees C) and PVC plasticized with CL (40.5 degrees C). Tensile tests indicated that PVC plasticized using KCL showed a 37 higher of elongation at break than PVC plasticized by CL and 30 higher than PVC plasticized by DOP. The plasticizing mechanism was also investigated. Moreover, exudation, volatility, and extraction tests, along with TGA indicated that the presence of ketal groups effectively improved the migration resistance of plasticizer and the thermal stability of PVC blends. Taken together, introducing ketal groups into plasticizer might be an effective strategy for improving its plasticizing efficiency.