Posidonia Oceanica waste was used as reinforcement in a polyethylene matrix and the obtained composites were characterised by a tensile test and morphological analysis. The fibrous material derived from P. Oceanica wastes was characterised by morphological, thermal and chemical analysis, and a subsequent treatment with sodium hydroxide (NaOH) at different weight content (2, 5 and 10 wt%) was considered as an optimised method for surface modification of pristine fibres (PO).
The TGA analysis and morphological investigation of the treated fibres selected the 5 wt% of NaOH as the best treatment.
Matrix compatibilisation with maleic anhydride grafted polyethylene was also considered and the effect on both grafting procedure and alkali treatment was studied for composites containing 20 wt% of fibres.
The results confirmed that it is possible to aim for a revalorisation of coastal algae and seaweed wastes as raw material for polyolefin matrix composites, even without applying a strong chemical treatment to the waste.