Morphology, mechanical, and rheological properties of poly(lactic acid)/ethylene acrylic acid copolymer blends processing via vane extruder

Abstract

This work aimed to study, for the first time, the melt blending of poly(lactic acid) (PLA) and ethylene acrylic acid (EAA) copolymer by a novel vane extruder to toughen PLA. The phase morphologies, mechanical, and rheological properties of the PLA/ EAA blends of three weight ratios (90/10, 80/20, and 70/30) were investigated. The results showed that the addition of EAA improves the toughness of PLA at the expense of the tensile strength to a certain degree and leads the transition from brittle fracture of PLA into ductile fracture. The 80/20 (w/w) PLA/EAA blend presents the maximum elongation at break (13.93%) and impact strength (3.18 kJ/m 2 ), which is 2.2 and 1.2 times as large as those of PLA, respectively. The 90/10 and 80/20 PLA/EAA blends exhibit dropletmatrix morphologies with number average radii of 0.30-0.73 lm, whereas the 70/30 PLA/EAA blend presents an elongated cocontinuous structure with large radius (2.61 lm) of EAA phase and there exists PLA droplets in EAA phase. These three blends with different phase morphologies display different characteristic linear viscoelastic properties in the low frequency region, which were investigated in terms of their complex viscosity, storage modulus, loss tangent, and Cole-Cole plots. Specially, the 80/20 PLA/EAA blend presents two circular arcs on its Cole-Cole plot. So, the longest relaxation time of the 80/20 blend was obtained from its complex viscosity imaginary part plot, and the interfacial tension between PLA and EAA, which is 4.4 mN/m, was calculated using the Palierne model.

Interfacial adhesion and water resistance of stainless steel–polyolefin improved by functionalized silane

“…Blends with high LLDPE content (60 wt% and 80 wt%) showed clear deviation from semicircular shape (circular arc with tail and linear shape, respectively) indicating coexisting phases in different internal structures such as the droplet‐matrix morphology or co‐continuous morphology . The deviations from the semicircular shape indicate heterogeneity between phases in addition to increased viscosity of the blends .…”

Stiff-Elongated Balance of PLA-Based Polymer Blends

“…observed by Zhao et al [57] in mixtures of PLA and an ethylene-acrylic acid copolymer (EAA). When increasing the amount of EAA, the viscosity of the mixture decreased, indicating lower elastic energy as well as a smaller radius of the circular arcs in the highfrequency region of the Cole-Cole graphs.…”

“…In addition, the first relaxation is observed for the dominant phase, i.e., PLA, and the second semi-circle corresponds to the dispersed phase. Previous is related to two relaxation mechanisms of different morphologies, indicating coexisting phases in different internal structures such as droplet morphology or a co-continuous morphology [57,58].…”

Biodegradable Foaming Material of Poly(butylene adipate-co-terephthalate) (PBAT)/Poly(propylene carbonate) (PPC)

“…The higher complex viscosity of PPC and lower sensitivity to external force shear resulted in a smoother curve than that of E-PBAT. [47] The viscoelasticity of the blends was strongly affected by the shear frequency and the composition of the blends. The relaxation process was affected by the entire blend system at high frequency region and originated from the deformation of dispersed particles at low frequency region.…”