Influence of nanosilica and chain extender on the mechanical behavior of poly(lactic acid)/poly(butylene adipate-co-terephthalate) blends

The effect of incorporating different percentages of hydrophobic and hydrophilic nanosilica (HPB and HPL NS) particles and chain extender (CE) on the mechanical behavior of poly(lactic acid)/poly(butylene adipate-co-terephthalate) (PLA/PBAT) blends was evaluated. The mechanical behavior of the samples was explained using different theoretical models. Microscopic studies showed that adding both types of NS particles and CE led to more uneven surfaces for blends. Also, no obvious aggregations were observed in both blend nanocomposites, and both kinds of NS particles were mainly present in the PBAT phase. Except for the blend containing 1 phr HPB NS particles, which revealed a continuous morphology, all the PLA/PBAT blends containing both types of NS particles indicated a droplet-matrix morphology. The more the NS content, the more uniform the PBAT distribution. Adding CE in the blends improved Young's modulus, yield strength, and elongation-at-break to a particular loading of CE (2 phr), while these properties were diminished after introducing more CE. Also, the most improvements in the yield strength (45%) and Young's modulus (35%) were seen for the PLA/PBAT (75/25 w/w) containing 2 phr CE and 5 phr HPL NS particles. Besides, a good agreement was observed for experimental values and theoretical models for all samples. Comparison of the experimental and theoretical data for the tensile strength of PLA/PBAT blends containing (a) HPB and (b) HPL NS particles. image