Preparation of Supertough Polylactide/Polybutylene Succinate/Epoxidized Soybean Oil Bio-Blends by Chain Extension

Poly(lactic acid) (PLA) was toughened using ductile biodegradablepoly(butylene succinate) (PBS) and biobased epoxidized soybean oil(ESO). A reactive reagent (Joncryl ADR 4370 S) was introduced forpreparing reactive compatibilized bio-blends by melt-processing in situ. The compatibility, rheology, crystallization, mechanicalproperties, and microstructures of the PLA, PBS, and ESO bio-blendswere measured using theoretical compatibility predication, Fouriertransform infrared (FTIR) spectroscopy, dynamic mechanical analysis(DMA), dynamic rheological analysis, wide-angle X-ray diffraction(WAXD), mechanical tests, field-emission scanning electron microscopy(FESEM), and optical stereomicroscopy (OM). The introduction of 4370S induced graft copolymerization in situamong PLA, PBS, and ESO and considerably improved the bio-blend compatibility.The PBS and PLA crystal structures were not altered, while the PBScrystallinity reduced in the bio-blends because of chain extensionsamong the components. The refined PBS particles and evenly distributedESO drops in the PLA matrix were ascribed to enhanced adhesion andimproved compatibility due to the formation of graft copolymers in situ. Owing to the combination of ESO and 4370S, the supertough PLA and PBS bio-blends exhibited a tensile strainat break and notched impact strength above 300% and 30 kJ/m(2), respectively. Biodegradableand biobased supertough PLA/PBS/ESO blendswere fabricated by chain extension via one-step insitu reactive compatibilization.

Automated summary

Poly(lactic acid) (PLA) was toughened by incorporating ductile biodegradable poly(butylene succinate) (PBS) and biobased epoxidized soybean oil (ESO). The addition of a reactive reagent (Joncryl ADR 4370 S) enabled the formation of graft copolymers in situ, resulting in significantly improved compatibility and mechanical properties of the bio-blends. The study utilized various characterization techniques to investigate the compatibility, rheology, crystallization, mechanical properties, and microstructures of the bio-blends. The biodegradable and biobased supertough PLA/PBS/ESO blends exhibited excellent tensile strain at break and impact strength, attributed to the combination of ESO and 4370S.