Investigation of PLA composites modified by butadiene rubber using the compatibilization method

Application of biodegradable polylactic acid (PLA) is limited by its poor toughness and processability. This research focused on modifying PLA using butadiene rubber (BR) and epoxy butadiene rubber (EBR) as a toughening material. To enhance the compatibility between PLA and BR, and dicumyl peroxide (DCP) and acetyl tributyl citrate (ATBC) was introduced into the BR/PLA or EBR/PLA system to prepare BR/PLA-S or EBR/PLA-S by melt blending. The results showed that the optimal composition of modified-BR/PLA was that the mass ratio of PLA/BR/DCP/ATBC was 80/20/0.15/4. The impact strength and elongation at break of the BR/PLA-S and EBR/PLA-S were 8.73 kJ/m 2 and 105.6%; and 11.18 kJ/m 2 and 157.9% respectively. It improved the toughness of PLA, and the toughening effect of EBR was better than that of BR. The peak intensity of the C=C bond (3006 cm -1 ) in the FTIR spectra of the modified-BR/PLA weakened, and the peak area of the CH 2 bond (2918 cm −1 ) increased, occurring a cross-linking reaction between BR (or EBR) and PLA. Tg, Tc and Tm of the BR/PLA-S and EBR/PLA-S were 58.44°C, 92.53°C and 170.13°C; 55.0°C, 87.5°C and 167.66°C respectively, lower than Tg and Tc of PLA, and higher than Tm of PLA, suggesting that modified-BR improved processability and thermal stability of PLA composites. The successful preparation of BR-based toughening agent using an environmental-friendly system broadened the use of BR and PLA with the truly-sustainable developments.