PLA/SiO₂ composites: Influence of the filler modifications on the morphology, crystallization behavior, and mechanical properties

Abstract

ABSTRACT Films of an architecturally modified poly(lactic acid) (PLA REx ) with three different types of fumed silica nanofillers (SiO 2 ) were processed through reactive extrusion‐calendering in a pilot plant. The effects of the SiO 2 type on both the dispersion and the crystallization behavior under dynamic and isothermal conditions are investigated using transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The mechanical properties are assessed by tensile testing. TEM micrographs showed that the improved chemical affinity of both surface‐treated SiO 2 toward PLA REx end groups did not improve particle dispersion. DSC results revealed that untreated SiO 2 nucleated PLA REx more efficiently than both surface‐modified silicas. The activation energy for the isothermal crystallization process, as determined by an Arrhenius method, suggests that addition of untreated SiO 2 enhances the crystallization rate of PLA REx . However, it seems that the tensile behavior remained unchanged whether silicas were added or not. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45367.