Biomaterial from argan shells: Size effect on thermal conductivity

Abstract

The argan tree, Argania spinosa (L.) Skeels, also known as iron wood, is an endemic and emblematic tree in the center and southwest of Morocco. The main product of this millenary tree is argan oil, known for its cosmetic and therapeutic virtues. One of the co-products of the production of argan oil is the shell. This co-product, which represents 80% of the weight of the argan fruit, remains an untapped resource. It is mainly used for heating and is sold for a relatively low price. To enhance this co-product, the shells by sorting, grinding, and sieving them, then binding the particles in adhesive. Three materials are based on three particle sizes of shell grains. The size-selected particles are bound with a powder adhesive that is produced from a precatalyzed urea and formaldehyde resin, with water used as a nontoxic solvent. In the cured state, the adhesive and the argan shell grains become a crosslinked, insoluble, infusible material. In this study, we focused on measuring the thermal conductivity of the three ranges of the argan shell using a thermal conductivity analyzer (l-Meter EP500e); the measurements consist of applying a flux of variable heat in a block comprising a sample taken between two plates. We also measured the thermal conductivity of the argan tree nuts without glue. The results show a greater improvement in the thermal conductivity l of the reinforced materials for small particles than for large particles. The composites are thermally stable compared to the shell of argan tree nuts without glue.