Modelling the structure-property relationships of high performance PBAT-based biocomposites with natural fibers obtained from Chamaerops humilis dwarf palm

Two fibrous fillers were achieved from stalks and leaves of Chamaerops humilis dwarf palm and tested as reinforcing agents for poly(butylene adipate co-terephthalate) (PBAT)-based composites. The influence of filler type and content on the morphomechanical properties of the green composites was assessed. The outcomes of tensile tests pointed out that both fillers are strong candidates to overcome the two main limiting aspects of PBAT, that is, the lack of both stiffness and cost-effectiveness, while preserving its stretchability and environmental sustainability. The remarkable stiffness increments (up to 300%), combined with fair retention of stretchability (33%) and doubled resistance, led to the fabrication of biocomposites with toughness values as high as 20-25 MJ/m(3). These results could be ascribed to the combination of several factors, including the formation of an extensive and robust interphasic region. This latter, ascribed to the chemical affinity between aromatic parts of fillers and matrix, presented different features in the two types of fillers, thus endowing resulting biocomposites with a broad array of mechanical performance, which can be predicted by introducing opportune modifications to Halpin-Tsai model which allow considering the crucial role of interphase.