The influence of Scutellaria baicalensis extract obtained from traditional Chinese herbal medicine on the thermo‐oxidative degradation and stabilization of plasticized polylactic acid

Abstract

AbstractDespite the advantage of biodegradability, polylactic acid (PLA) has some processing and application drawbacks, such as poor thermal oxygen stability. Herein, the modified PLA samples were prepared by mixing PLA granules, acetyl tributyl citrate (ATBC), and Scutellaria baicalensis extract (SBE) obtained from traditional Chinese herbal medicine. Results revealed that the introduction of SBE improves the thermal oxidation stability of PLA‐ATBC matrix. When the content of SBE was 2.0 wt%, the oxidation onset temperature value of the modified sample is increased by 68°C versus PLA‐ATBC. The excellent antioxidant performance is attributed to the outstanding free radical quenching capacity of SBE. The introduction of SBE slightly decreased the degradation rate of PLA‐ATBC in an enzyme degradation process, which may be due to the SBE reducing the enzyme activity. Moreover, the addition of small amounts of SBE into the PLA‐ATBC matrix has little influence on polymer crystallization behavior, just decreased by ca. 8.6% (PLA‐ATBC‐SBE2.0 sample). SBE has no obvious effect on the water vapor permeability and surface wettability of PLA‐ATBC membranes. All results reveal that the SBE could play a role in the thermal oxygen stability of PLA‐ATBC without much change in its other performances.