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

Authors

  • Yong-Qing Zhao,

    1. National Engineering Research Center of Novel Equipment for Polymer Processing, South China University of Technology, Guangzhou, Guangdong, People's Republic of China
    2. The Key Laboratory of Polymer Processing Engineering of Ministry of Education, South China University of Technology, Guangzhou, Guangdong, People's Republic of China
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  • Fu-Quan Chen,

    1. National Engineering Research Center of Novel Equipment for Polymer Processing, South China University of Technology, Guangzhou, Guangdong, People's Republic of China
    2. The Key Laboratory of Polymer Processing Engineering of Ministry of Education, South China University of Technology, Guangzhou, Guangdong, People's Republic of China
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  • Zheng-Huan Wu,

    1. National Engineering Research Center of Novel Equipment for Polymer Processing, South China University of Technology, Guangzhou, Guangdong, People's Republic of China
    2. The Key Laboratory of Polymer Processing Engineering of Ministry of Education, South China University of Technology, Guangzhou, Guangdong, People's Republic of China
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  • Yan-Hong Feng,

    1. National Engineering Research Center of Novel Equipment for Polymer Processing, South China University of Technology, Guangzhou, Guangdong, People's Republic of China
    2. The Key Laboratory of Polymer Processing Engineering of Ministry of Education, South China University of Technology, Guangzhou, Guangdong, People's Republic of China
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  • Jin-Ping Qu

    Corresponding author
    1. National Engineering Research Center of Novel Equipment for Polymer Processing, South China University of Technology, Guangzhou, Guangdong, People's Republic of China
    2. The Key Laboratory of Polymer Processing Engineering of Ministry of Education, South China University of Technology, Guangzhou, Guangdong, People's Republic of China
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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/m2), 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 droplet-matrix morphologies with number average radii of 0.30–0.73 μm, whereas the 70/30 PLA/EAA blend presents an elongated co-continuous structure with large radius (2.61 μm) 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. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40146.

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