Valorization of hemp core residues: Impact of NaOH treatment on the flexural strength of PP composites and intrinsic flexural strength of hemp core fibers
Journal article, 2020

Hemp core is a lignocellulosic residue in the production chain of hemp strands. Huge amounts of hemp core are gathered annually in Europe (43,000 tons) with no major application end. Such lignocellulosic wastes have potential as filling or reinforcing material to replace synthetic fibers and wood fibers in polymer composites. In this study, hemp core biomass was treated under different NaOH concentrations and then defibrated by means of Sprout Waldron equipment to obtain single fibers. Polypropylene matrix was reinforced up to 50 wt.% and the resulting hemp core fibers and the flexural properties were investigated. The results show that the flexural strength of composites increased with the intensity of NaOH treatment. The effect of NaOH was attributed to the removal of extractives and lignin in the fiber cell wall leading to improved interfacial adhesion characteristics. Besides, a methodology was established for the estimation of the intrinsic flexural strength of hemp core fibers. The intrinsic flexural strength of hemp core fibers was calculated to be 940 MPa for fibers treated at 10 wt.% of NaOH. In addition, a relationship between the lignin content and the intrinsic strength of the fibers was established.

Flexural strength

Intrinsic properties

Composites

Chemical treatment

Hemp core

Author

Fabiola Vilaseca

University of Girona

Chalmers, Industrial and Materials Science

Ferran Serra-Parareda

University of Girona

Eduardo Espinosa

Universidad de Córdoba

Alejandro Rodríguez

Universidad de Córdoba

Pere Mutjé

University of Girona

Marc Delgado-Aguilar

University of Girona

Biomolecules

2218-273X (eISSN)

Vol. 10 6 823

Subject Categories

Composite Science and Engineering

DOI

10.3390/biom10060823

More information

Latest update

3/29/2021