Analysis, Development, and Scaling-Up of Poly(lactic acid) (PLA) Biocomposites with Hazelnuts Shell Powder (HSP)

In this work, two different typologies of hazelnuts shell powders (HSPs) having different granulometric distributions were melt-compounded into poly(lactic acid) (PLA) matrix. Different HSPs concentration (from 20 up to 40 wt.%) were investigated with the aim to obtain final biocomposites with a high filler quantity, acceptable mechanical properties, and good melt fluidity in order to be processable. For the best composition, the scale-up in a semi-industrial extruder was then explored. Good results were achieved for the scaled-up composites; in fact, thanks to the extruder venting system, the residual moisture is efficiently removed, guaranteeing to the final composites improved mechanical and melt fluidity properties, when compared to the lab-scaled composites. Analytical models were also adopted to predict the trend of mechanical properties (in particular, tensile strength), also considering the effect of HSPs sizes and the role of the interfacial adhesion between the fillers and the matrix.

Automated summary

Two different typologies of hazelnuts shell powders were melt-compounded into a PLA matrix with varying concentrations to achieve biocomposites with high filler quantity and acceptable mechanical properties. The scaled-up composites showed improved mechanical and melt fluidity properties compared to lab-scaled composites due to efficient removal of residual moisture. Analytical models were used to predict mechanical properties trend and analyze the interfacial adhesion between fillers and matrix.