Effect of Ethylene/butyl methacrylate/Glycidyl Methacrylate Terpolymer on toughness and biodegradation of poly (l-lactic acid)

The super toughed poly(l-lactic acid) (PLLA) blends with various content of Ethylene/butyl methacrylate/Glycidyl Methacrylate Terpolymer (GEBMA) were prepared by melt compounding. The blend was an immiscible system but had good compatibility due to the chemical reaction between the epoxy groups of GEBMA and the end group of PLLA during the blending process. The addition of GEBMA suppressed the cold crystallization and non-isothermal melt crystallization of PLLA. GEBMA was a very effective toughening agent for PLLA. The addition of only 15 wt% GEBMA, the elongation at break and impact strength of the blend were significantly improved compared to neat PLLA, which were 63 and 18 times that of neat PLLA, respectively. Scanning electron microscopy (SEM) images of the impact fracture surfaces of the blends showed a large amount of cavities and plastic deformation in the blend, which induced energy dissipation and therefore led to the improvement in toughness of the PLLA/GEBMA blends. For the PLLA/GEBMA blown films, the addition of GEBMA significantly improved the flexibility of PLLA/GEBMA blown film. The tear strength reached a maximum of 143.5 kN/m in the machine direction (MD) and 166.7 kN/m in the transverse direction (TD). Moreover, the biodegradation of PLLA was enhanced after blends preparation.