Influence of chemical treatments on adhesion properties of hemp fibres

In addition to be an environmentally friendly material, hemp fibres are also inexpensive reinforcements in thermoplastics or concrete composites, due to their intrinsic mechanical, thermal and acoustic properties. The morphology of hemp fibres has been chemically modified in order to enhance the matrix/fibre interface and has been examined by Scanning Electron Microscopy (SEM). In this paper, Gas Chromatography (GC) and Atomic Force Microscopy (AFM) were used to investigate the influence of treatments on the composition of hemp fibres and also on the micro-adhesive interactions between a silica colloidal probe and the surface of the fibres using Chemical Force Microscopy (CFM). Microscopy studies and chemical analysis showed that each treatment tends to lead to a morphology of interconnected web-like structure of hemp fibres. It was found that on an average, the adhesion force, contribution of capillary force and Van der Waals’ forces, is higher in the case of NaOH treatment.

Impact of chemical treatments on the surface properties of hemp fibres. Atomic Force Microscopy imaging of untreated fibres (a), and fibres chemically treated with NaOH (b), EDTA (c) and PEI (d)Figure optionsDownload high-quality image (115 K)Download as PowerPoint slideResearch highlights
► Chemical treatments modify the structure of hemp fibres.
► Each treatment tends to lead to a morphology of interconnected web-like structure.
► Adhesion properties, measured with Colloidal Force Microscopy, change according to treatments.