Poly(lactic acid)/graphene and poly(lactic acid)/carbon nanotube nanocomposites were prepared by an easy and low-cost method of melt blending of preliminary grinded poly(lactic acid) (PLA) with nanosized carbon fillers used as powder. Morphological, structural and mechanical properties were investigated to reveal the influence of carbon nanofiller on the PLA–based composite. The dependence of tensile strength on nanocomposite loading was defined by a series of experiments over extruded filaments using a universal mechanical testing instrument. The applying the XRD technique disclosed that compounds crystallinity significantly changed upon addition of multi walled carbon nanotubes. We demonstrated that Raman spectroscopy can be used as a quick and unambiguous method to determine the homogeneity of the nanocomposites in terms of carbon filler dispersion in a polymer matrix.
The industrial processing of tomato leads to substantial amounts of residues, typically known as tomato pomace or by-products, which can represent as much as 10% by weight of fresh tomatoes. At present, these residues are either used as feedstock for animals or, in the worst case, disposed of in landfills. This represents a significant waste because tomato pomace contains high-value compounds like lycopene, a powerful antioxidant, cutin, which can be used as a starting material for biopolymers, and pectin, a gelling agent. This article presents an overview of technologies that valorize tomato by-products by recovering added-value compounds as well as generating fuel for energy production. These technologies include operations for extraction, separation, and exploitation of lycopene, cutin and pectin, as well as the processes for conversion of the solid residues to fuels. Data collected from the review has been used to develop a biorefinery scheme with the related mass flow balance, for a scenario involving the tomato supply chain of Regione Campania in Italy, using tomato by-products as feedstock.
This paper reports the experimental results of an on-going project running at lab-scale and aimed at the valorization of roasted hazelnut cuticles through both chemical (i.e., solvent extraction) and thermochemical treatment (i.e., torrefaction) routes. In particular, the potential of using water as a green solvent for the extraction of bioactive compounds (i.e., substances of chemical-food-pharmaceutical interest, such as the polyphenols) contained in residues originated by industrial processing of hazelnuts has been investigated, applying the conventional laboratory Soxhlet extraction procedure. A subsequent valorization stage has been explored for the spent post-extraction residues versus the “as collected” ones; they lend themselves to become “renewable” solid fuels thanks to torrefaction, which is a “mild” thermochemical conversion process. The obtained results are first presented in terms of theoretical yields of the bioactive compounds of interest with respect to the original mass of hazelnut residue; in addition, the findings on torrefaction are discussed in terms of performance indexes with respect to the torrefied fuel and quantitatively expressed as correlations as a function of temperature.