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Poly(lactic acid)-layered silicate nanocomposites: The effects of modifier and compatibilizer on the morphology and mechanical properties

Cumkur, Eda Acik
Baouz, Touffik
Yılmazer, Ülkü
Poly(lactic acid) (PLA) based nanocomposites were prepared to investigate the effects of types of nanoclays. Five different organically modified nanoclays (Cloisites((R))15A, 25A, and 30B, and Nanofils((R))5 and 8) were used. Two rubbery compatibilizers, ethylene-glycidyl methacrylate (E-GMA) and ethylene-butyl acrylate-maleic anhydride, were used in the nanocomposites as compatibilizer-impact modifier. The degree of clay dispersion, the chemical compatibility between the polymer matrix and the compatibilizers, and changes in the morphology and mechanical properties of the nanocomposites were investigated. The mechanical properties and the morphological studies showed that the interactions between the different compatibilizers and PLA resulted in different structures and properties; such that the dispersion of clay, droplet size of the compatibilizer, and tensile properties were distinctly dependent on the type of the compatibilizer. Compatibility between C25A, C30B, and E-GMA resulted in the best level of dispersion, leading to the highest tensile modulus and toughness among the compositions studied. In the mentioned nanocomposites, a network structure was formed owing to the high reactivity of the epoxide group of GMA towards the PLA end groups resulting in high impact toughness. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42553.