Valorization of hemp fibres in eco-composites from bioplastics

In the present work, raw hemp fibres were used to reinforce a commercial biopolyester, namely poly(1,4-butylene adipate-co-terephthalate), thus improving its mechanical properties. To this purpose, an appropriate surface treatment of the fibres was necessary to enhance the fibre/matrix adhesion. To reduce the intrinsic hydrophilicity of the hemp fibres, they were preliminary washed with diluted NaOHaq in mild conditions and then treated with a green process based on a novel soft plasma jet (developed by Nadir Srl). In the present case, this system allowed the use of a Ar + O2 gas mixture, coupled with deposition of methyl metacrylate. Thermogravimetric analysis (TGA) was carried out to evaluate thermal and thermo-oxidative stability of the ensuing composites and determine the fibre content. Morphological analysis of fibres and composites was performed by scanning electronic microscopy (SEM) coupled with EDX probe for element microanalysis. The eco-composites were investigated in terms of rheological, mechanical, and dynamic-mechanical behaviour in comparison with the neat biopolyester matrix. Specific mechanical testing were performed on fibres before and after surface modification treatments