Effect of treatment type of natural fibers on the rheological and micromechanical behavior of polyvinyl alcohol composites

The viscoelastic and mechanical performance of sustainable raw materials on biodegradable matrices provide insights into how to develop and improve materials that contribute to the circular economy. Thus, we aim to evaluate the effect of conventional (acid or alkali) and dual (alkali/acid-ultrasound) treatment on Agave fibers, as well as their rheological and micromechanical performance on polyvinyl alcohol (PVA)-based composites. TGA results indicate that the treatments promote the removal of moisture, waxes, pectin, hemicellulose, and lignin from the fibers to different extents. PVA matrix containing modified fibers exhibits low viscosity, flux index, and critical shear values, indicating a high interaction and dispersion of the filler in the matrix. Furthermore, tensile tests and theoretical predictions of micromechanics-based finite element analysis show evidence that the modified fiber type provides a different stress transfer ratio (S) than in the matrix, which changes Young's modulus values. The results indicate that Agave fibers modified by dual treatment are a useful filler to produce soft or stiff PVA composites when looking for potential applications in the mobility industry or other fields like the packaging.