Role of Phase Compatibility in Gas Barrier Improvement of Biodegradable Polymer Blends for Food Packaging Application
2022
Wu, Feng | Feng, Dong | Xie, Yu-hui | Xie, Delong | Mei, Yi
The application of biodegradable polymers as next-generation food packaging is mainly hampered by their inadequate mechanical and gas barrier properties. To solve the above problems, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with a high gas barrier was introduced into lab-made supertough biodegradable matrix high-impact polybutylene succinate (HIPBS.) By regulating the content of PHBV and interfacial compatibility, a blend with high barrier properties and excellent mechanical toughness was achieved. The introduction of low content of PHBV (10 wt %) greatly reduced the gas permeability of the material. With 10 wt % PHBV, the oxygen (23 °C, 0% humidity) and water vapor permeabilities (38 °C, 100% humidity) of the matrix are decreased by 72 and 71% respectively, due to the decreased solubility as calculated based on a “time-lag” method. The sample also exhibited supertoughness with a notched impact strength higher than 650 J/m and high melt strength ensuring its stretch-shaping processability. When the PHBV content was further increased to 20 and 30 wt %, the gas permeability of the material instead increased due to the microscopic phase separation between PHBV and HIPBS. These results highlight the key role of interfacial compatibility in gas barrier improvement; a substantial increase of barrier performance can be achieved even with the addition of low content of the high-barrier phase.
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