Ricerc@Sapienza

Despite the advantages offered by natural fibre-based thermoplastic composites in terms of environmental impact and cost, their mechanical performance is generally lower than that of synthetic counterparts. Hybridisation with mineral fibres (basalt) can broaden the industrial applications of natural fibre reinforced composites. The present study focused on the performance of injection-moulded short basalt fibre, hemp fibre and hemp/basalt fibre hybrid high density polyethylene (HDPE) composites.

The Achilles heel of thermoplastic natural fibre composites is their limited durability. The
environmental degradation of the mechanical properties of hemp and hemp/basalt hybridreinforced
high-density polyethylene (HDPE) composites has been investigated with a special focus
on the effects of water ageing and accelerated ageing, including hygrothermal and UV radiation.
Modification of the matrix was carried out using a maleic anhydride high-density polyethylene
copolymer (MAPE) as a compatibilizer. Hybridization of hemp fibres with basalt fibres and the

This study deals with the development and optimization of hybrid composites integrating microcrystalline cellulose and short basalt fibers in a polypropylene (PP) matrix to maximize the mechanical properties of resulting composites. To this aim, the effects of two different coupling agents, endowed with maleic anhydride (MA-g(grafted)-PP) and acrylic acid (AA-g-PP) functionalities, on the composite properties were investigated as a function of their amount.

The effects of the integration of continuous sheets of randomly oriented multi-walled carbon nanotubes on the low velocity impact behavior of cross-ply carbon/epoxy laminates have been investigated. Three different energy levels were used, namely 5 J, 10 J, and 20 J and significant reductions in delaminated area in the range 11%–39% compared to the baseline laminates were achieved by incorporating interleaves at each 0/90 interface. This resulted in a better flexural damage tolerance of modified laminates.

The aim of this experimental investigation is to assess the response to low velocity impacts of green sandwich
structures made of agglomerated cork encapsulated between two thin flax/epoxy face sheets. Three different
cork densities were considered to assess their role on the response to impulsive loading, both in low and high
strain rate conditions by Split Hopkinson Pressure Bar (from 90 to 238 1/s). The performance of these structures
has been compared to that obtained with similar specimens using a traditional synthetic foam core. Despite the

The increasing use of natural fibre composites in at least semi-structural applications along with a demand for a fast and accurate damage detection for quality purpose and in-service reliability promote a need for non-contact non-destructive testing techniques. To this purpose, ultrasound is probably one of the most widely used testing techniques but the need of a coupling fluid like water limits its use with natural fibre composites.