ABSTRACT In this study, a fully biobased poly(lactic acid) (PLA) composite with excellent toughness was prepared by reactive blending, in which biodegradable poly(4‐hydroxybutyrate) (P4HB) served as the flexible toughening phase and the environmentally friendly epoxidized soybean oil (ESO) served as the compatibilizer. FTIR and 1 HNMR results indicated that the epoxy groups in ESO have reacted with the hydroxyl/carboxyl groups in PLLA/P4HB. Effects of the composition ratio on the mechanical, thermal and rheological properties of the composite were investigated. Dynamic mechanical analyses showed that the glass transition temperatures of PLLA and P4HB in the mixture decreased after the addition of ESO, indicating that ESO acted as the plasticizer to a certain extent. Tensile experiments showed that the elongation at break of PLLA composites increased significantly with the increase of P4HB content in the presence of ESO, and the notched impact strength also increased significantly. The blends with the PLLA/P4HB ratio fixed at 40/10 exhibited excellent elongation and impact strength, the elongation at break and the notched impact strength nearly reached 219.7% and 38.3 kJ/m 2 , which were 52 times and 11 times that of neat PLLA, respectively. The synergistic effect of P4HB and ESO contributed to the improvement of the mechanical performance.
Xu et al. (Fri,) studied this question.