Dramatic Improvement in Toughness of PLLA/PVDF Blends: the Effect of Compatibilizer Architectures

Reactive comb (RC) polymers with different molecular architectures have been successfully synthesized by copolymerizing methyl methacrylate (MMA), glycidyl methacrylate (GMA), and a series of MMA macromer with different molecular weights. The prepared RC polymers with different lengths of side chains were applied as compatibilizers in an immiscible poly(l-lactic acid)/poly(vinylidene fluoride) (PLLA/PVDF) blend, and it was found that the RC polymers with moderate length of side chain (e.g., M-n = 4800 g mol(-1)) displayed better compatibilizing efficiencies than RC polymers with short side chain (e.g., M-n = 2400 g mol(-1)) and let alone the reactive linear (RL) polymers without side chains. The thus obtained PLLA/PVDF blends with PLLA as a matrix will provide excellent adhesion with the surfaces of the metals and cells, and it was found that RC polymers endowed the PLLA/PVDF blend with excellent toughness and the RC-compatibilized blend could be uniaxially stretched to a maximum draw ratio of 5 at room temperature (about 22 degrees C). FT-IR and XRD results showed that the nonpolar alpha phase of PVDF was completely transformed into the piezoelectric beta phase (more than 95%) during the stretching.