Plasticization effects of epoxidized vegetable oils on mechanical properties of poly(3-hydroxybutyrate)

The effect of various epoxidized vegetable oils as potential plasticizers for poly(3-hydroxybutyrate) (PHB) was evaluated in terms of changes in mechanical and thermal properties and morphology. PHB is a biodegradable aliphatic polyester obtained from bacterial fermentation. High stiffness and fragility are two of its main drawbacks. To overcome this behaviour, PHB was plasticized with various amounts of two different epoxidized vegetable oils: epoxidized linseed oil (ELO) and epoxidized soybean oil (ESBO). The total ELO and ESBO content varied in the range 5 phr (per hundred resin) to 20 phr and plasticized PHB materials were obtained by melt extrusion and compounding followed by injection moulding. The results show that the plasticizing effect provided by ELO is more efficient than that by ESBO with balanced properties at a concentration of 10 phr ELO. ELO addition leads to an improvement in mechanical ductile properties with a noticeable increase in elongation at break and impact absorbed energy. With regard to thermal properties, the addition of both ELO and ESBO leads to a marked increase in thermal stability of PHB. All these findings suggest that addition of 10 phr ELO leads to optimized PHB formulations with potential uses in technical applications. (c) 2016 Society of Chemical Industry