Evolution of the mechanical and morphological properties of two hemp cultivars (santhica 27 and félina 34) during the dew-retted

Abstract

The hemp is easy to cultivate in the East of France. SADEF, specialist in plant nutrition, studied this culture since 2013. But to extract the fiber, the stem must be retting. Actually, the dew retted is the most used in France. The retted is a very hazardous stage: if the stem is under-retted, the fiber extraction will be difficult; or if the stem is over-retted; the fiber properties will be degraded. Many factors (the cultivar, the weather, the duration...) [1–4] impact the fiber quality. This study observes the evolution of the mechanical and morphological properties of two hemp cultivars during the dew-retted. Two cultivars, Santhica 27 and Felina 34 were cultivated in 2020 in the East of France by SADEF. Every week, dew-retted stems were selected during eight weeks. The evaluation of the fiber quality was performed at the LPMT (Laboratoire de Physique et de Mécanique Textile) in Mulhouse, France. The color was measured by the DataColor. The fiber linear density was measured by the VIBROMAT Me followed by its tensile test performed by FAVIMAT [5]. All data were analyzed by ANOVA method. The fine fiber proportion increased during the retted. However, the tenacity decreased. At the retted end, there was no significant difference between the two cultivars mechanical properties.