Properties of Frost-Retted Hemp Fibers for the Reinforcement of Composites

Frost-retted hemp fibers were investigated to assess their suitability for composite applications. Chemical analysis of frost-retted hemp fibers highlighted a high amount of solubles (pectins) at the fibers surface and a low lignin content in the fibers that was attributed to an unfavorable synthesis of lignin in the cell wall due to the particularly cold temperature during hemp growth in the Nordic countries. The fibers tensile properties were considered at two different scales and the performances of hemp/PLA composites were assessed. Recommendations were provided for the use of frost-retted hemp fibers in the reinforcement of thermoplastic composites.