Journal of Materials Science Research and Reviews

This article is a review of the state of the art of the last decade on new materials based on cotton stem fibers (CTF) and natural binders such as Grewia Venusta Fresen bark, hulls fruits of Parkia Biglobosa, calyces of Bombax Costatum, etc.

The results reported in the literature revealed respectively that lignin and cellulose are present in plant materials such as CTF and binders in proportions of 20-26% and 3.82-32.95% respectively, then 32- 46% and 22.58-60.32%, which indicates the presence of mucilages and fibers. For better structuring of these composites, the pressing temperatures obtained in the previous works are of the order of 110 to 240 ° C. It has been reported that a 15% increase in binder powder in the base mix or an increase in fiber size from 0.063-0.63mm to 1.25-2mm leads to a decrease in the density of 10-30% and thermal conductivity of 20-30%, respectively. The variation of the rate of binder extract from 10 to 15% has no significant effect on the mechanical characteristics such as the Young's Modulus (MOE) (Modulus of Elasticity in Folding), the Modulus of Rupture in Folding (MOR), the Internal Liaison Force (IB). These characteristics decrease significantly when the pressing time and temperature vary from 5 to 25 min and from 140 to 180°C, respectively. They also decrease with the increase in the binder content and the granular class beyond the well-defined thresholds that we will best explore in our work.

We retain from previous work that an optimal formulation for a better material consists of homogeneous particles of 0.063-2 mm, a quantity of binder (60% by mass of powder or 10% by mass of extract) allowing better thermal insulation of conductivity 0.08 Wm^-1K^-1 at a temperature of 130°C for a pressing time of 10 to 15 minutes under a load of 10 to 15 KN.