Compatibilization of Poly(lactic acid)/Poly(propylene carbonate) blends by star-shaped multi-arm polymer with low molecular weight

Compatibilizing polymer blends via a facile and efficient manner is of great significance since polymer blends are practical in industrial applications but limit severely by poor compatibility. Herein, we propose a novel compatibilization strategy that star-shaped multi-arm polymer with low molecular weight can be an excellent compatibilizer for polymer blends. As an example of the concept, a modified tannic acid (mTA) with a starshaped multi-arm structure is fabricated to compatibilize biodegradable poly(lactic acid)/poly(propylene carbonate) (PLA/PPC) blend. Compared to traditional compatibilization methods, mTA shows higher compatibilization efficiency and lower limitation in distribution as mTA can exert compatibilization at the interface and in PLA and PPC phases. Consequently, mTA compatibilizes the PLA/PPC blend efficiently, leading to strikingly reduced size of PPC dispersed phase and optimized interface. The mechanism is revealed to stem from the reduced interfacial tension and regulated viscosity ratio. With the improved compatibility, PLA70/PPC30/mTA4 shows an elongation at break of 307.5 +/- 15.4 % and a toughness of 85.2 +/- 4.5 MJ/m3, which is 680 % and 800 % of that of PLA70/PPC30 respectively. We envision that this work provides a novel and facile compatibilization strategy and will promote the fabrication of high-performance polymer blends.