Improvement in thermal, mechanical, and barrier properties of biocomposite of poly (3-hydroxybutyrate-co-3-hydroxyhexanoate)/modified nano-SiO2

A biocomposite of poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH)/nano-SiO 2 modified with silane coupling agent KH570 (KH570-SiO 2 /PHBH) were prepared by solution-casting method. SiO 2 modified with KH570 exhibited improved uniform dispersion than that of pure nano-SiO 2 , and maximum thermal decomposition temperature range and crystallinity ( X c ) of KH570-SiO 2 /PHBH are 8.6°C and 119.7% higher than that of neat PHBH. Compared to the neat PHBH, a 75.4% and 70.8% improvement in Young's modulus and tensile strength were obtained. The water-vapor transmission and oxygen permeance of KH570-SiO 2 /PHBH decreased by 46.2% and 618.6%, respectively. The oxygen barrier property is equivalent to that of polyvinylidene chloride. Simultaneous enhancements on the thermal stability, mechanical, crystallizing, and barrier properties were mainly caused by uniform dispersion of modified nano-SiO 2 and solid interfacial bonding between filler and matrix.