Thermal and Mechanical Properties of a Polyhydroxyalkanoate Plasticized with Biobased Epoxidized Broccoli Oil
Résumé
Broccoli oil was epoxidized through a simple process with performic acid generated in situ without any metal catalyst. The resulting epoxidized broccoli oil (EBO) was characterized by 1H-NMR, 13C-NMR, Fourier transform infrared spectroscopy, and mass spectroscopy and after a 72-h reaction, and all initial double bonds were epoxidized without further degradation of the triglyceride. EBO was used thereafter as an additive in the formulation of polyhydroxyalkanoate (PHA) films. The effects of EBO on the thermal and mechanical properties of PHA were studied with chromatography combined with thermal and mechanical analysis. From static and dynamic mechanical characterizations of PHA/EBO blends, EBO could be considered a good plasticizer for PHA. When blended with PHA, EBO caused a decrease in the elastic modulus, an increase in the elongation at break, and a decrease in the glass-transition temperature. The beneficial effect of EBO on the thermal stability of the PHA was confirmed by thermogravimetric analysis combined with size exclusion chromatography. The water vapor permeability of the PHA-containing EBO films was also controlled by the EBO content