1st June 2020 - Mechanical properties of hemp fibers are impacted by humidity at nanoscale

1st June 2020 - Mechanical properties of hemp fibers are impacted by humidity at nanoscale

Hemp fibers are used in industrial applications for their mechanical properties and for their low density, which makes them suitable for environmentally friendly alternatives to petrochemical compounds in applications such as composite materials. However, their sensitivity to humidity can impact the properties of materials.

In the frame of the PhD thesis of Raphaël Coste supervised by L. Tetard (Univ. Central Florida), M. Molinari (LRN, URCA; CBMN, Univ. Bordeaux) and B. Chabbert (FARE), the effect of relative humidity in air on the local indentation modulus of hemp fibres was explored at the nanoscale so as to differentiate the behaviour of individual cell wall layers.

The indentation modulus of xylem and sclerenchyma fibres was determined by atomic force microscopy and displayed decreasing values with increasing air humidity percentage. However xylem and sclerenchyma behave differently as xylem fibres contain more water than sclerenchyma fibres during water sorption. The differences in lignin content and crystallinity of cellulose were assessed with Raman spectroscopy, further underlying the role the composition of plant fibres plays in water uptake.

Overall, the study deepens the understanding of the interplay between composition and moisture and their effects on nanomechanical properties of hemp, suggesting that materials derived from hemp bast fibres will exhibit more stable hygroscopic behaviour.

Read: Coste R, Pernes M, Tetard L*, Molinari M, Chabbert B*. Effect of the interplay of composition and environmental humidity on the nanomechanical properties of hemp fibers. ACS Sustainable Chemistry & Engineering 2020, 8, 16, 6381-6390. DOI

Contact: Dr Brigitte CHabbert, brigitte.chabbert@inrae.fr

Modification date : 06 June 2023 | Publication date : 29 May 2020 | Redactor : B. Chabbert / G. Paës