Enhancing the toughness of biodegradable polylactic acid (PLA) blends with minimal filler content meanwhile preserving their thermomechanical properties remains a highly desirable objective. Here, through a simple in situ mixing of PLA with cellulose nanocrystals (CNC) and cellulose nanocrystal nanofluids (CNCfs), the electrostatic interaction between CNCfs (+22.6 mv) and CNC (-9.07 mv) formed petal-like hybridized particles with CNCfs as the core and CNC particles as the outer layer. The rheological tests indicated a significant reduction in the zero-shear viscosity and storage modulus of PLA/CNCfs blends, while the viscosity of PLA/CNCfs@CNC slightly decreased but retained its storage modulus compared to pure PLA. The optimized PLA/CNCfs@CNC blends not only exhibited excellent melt processing performance, but also increased the elongation at break (increased by 184 % and 375 % at 8 °C and 45 °C, respectively) and enhanced toughness remarkably (increased by 3.5 and 3.3-fold at 8 °C and 45 °C, respectively) meantime retaining the modulus with 1 GPa. The addition of CNCfs@CNC hardly affects the glass transition temperature and thermo-mechanical properties of PLA. The dielectric properties of PLA/CNCfs1.0/CNC2.0 blends were maximized at 1000 Hz, reaching a value of 21, which can be attributed to the synergistic effect of multilayer interfacial polarization.
Keywords: Cellulose nanocrystals fluids; Mechanical properties; Polylactic acid.
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