The need for sustainable development has raised interest in using natural fibres as reinforcement in polymer composites to replace synthetic fibres. Many studies have been performed on composites made of one kind of reinforcement, i.e. 100% plant fibres (jute, hemp, flax, sisal) or 100% mineral fibres (basalt). The results have shown that generally natural fibre composites do not fully attain the expected levels of mechanical performance due to poor fibre/matrix interfacial adhesion, an issue that demands an in-depth analysis and optimization of the interface quality at the micro-scale. A great deal of research over last fifteen years has been carried out into the interface between natural fibres and a huge range of polymer matrix materials, but most of the suggested treatments depend on the use of chemicals that lower the green character of such natural fibres along with their mechanical properties. In this framework, this research project aims to specifically design greener surface treatments based on peptides (poly(amino acids)) with tailored polarity to increase the compatibility of natural fibres with a range of polymer matrices without adversely affecting the mechanical properties of the pristine fibres. This study will involve the characterization of treated fibres in terms of their mechanical and thermal properties to assess the effects of surface treatment and optimize the related process parameters. The indirect evaluation of the influence of interfacial adhesion on the composite properties will be performed by mechanical testing of the conventional, macro-scaled composites.
