Effect of biodegradable plasticizers on thermal and mechanical properties of poly(3-hydroxybutyrate)

The effects of biodegradable plasticizers on the thermal and mechanical properties of poly (3-hydroxybutyrate- co-3-hydroxyvalerate) (PHBV) were studied using thermal and mechanical analyses. Soybean oil (SO), epoxidized soybean oil (ESO), dibutyl phthalate (DBP) and triethyl citrate (TEC) were used as plasticizing additives. PHBV/plasticizer blends were prepared by evaporating solvent from blend solutions. The content of plasticizer in the blends was kept at 20wt%. Compatibility of plasticizer with PHBV was examined with differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). DPB and TEC were more effective than soybean oils (SO and ESO) in depression of the glass transition temperatures as well as in increasing the elongation at break and the impact strength of the films. From the thermal and mechanical properties of the plasticized PHBV, it could be concluded that TEC or DBP are better plasticizers than SO and ESO for PHBV.