CONICET | Buscador de Institutos y Recursos Humanos

There are a lot of researches that deal with the problem of concentration, arrangement and aspect ratio of fillers within a continuous phase. It is well-known that natural polymers, or biopolymers, are promising materials for the replacement of oil-derived polymers due to the environmental concerns. However, they present moderated to low mechanical resistance. This problem can be solved through the reinforcement of biopolymers with fibers. Natural fibers represent strong and eco-friendly materials that emerged as competitive reinforced fillers with respect to synthetic fibers such as carbon and glass fibers. In short fiber composites, fibers are included within the polymeric matrix making possible a random orientation and a high versatility of processing. Then, the optimum filler concentration required rendering a stronger composite material might be studied through theoretical models. Several theories predict the maximum volume fraction () of filler within a matrix to assure a random distribution. In this work the effect of fiber concentration at a fixed L/d aspect ratio on the mechanical properties of pectin composites was studied for applications in the field of engineering materials. Correlations between experimental volume fractions (exp), theoretical volume fractions (max) and mechanical parameters were made.Short Sisal Fiber Composites (SSFC) based on a pectin matrix were prepared and characterized mechanical and optically. Different concentrations of sisal fiber were proved in order to evaluate their reinforcement effect. Higher elastic modulus and tensile strength were observed as the amount of fiber content increases. Optical microscopy and ImageJ software were used to obtain a L/d = 2.8. Theoretical models were applied in order to calculate the maximum packing fraction (max) and its relationship with mechanical parameters of the composite. SSFC at 20 wt. % showed the best reinforcement properties agreeing with theoretical predictions.