Insights on the performance of modified agave fibers on polypropylene matrix: physicochemical and mechanical features

In this study, the structural (FTIR/XRD), morphological (SEM), thermal (DSC), and mechanical properties of composites made from polypropylene (PP)/ maleated polypropylene (PP-g-MA) were assessed as a function of the unmodified (UF) and modified agave fiber (MF) content (10, 20, 30, 40, and 50%). SEM analysis revealed a homogeneous distribution of the modified fibers in the PP matrix since the simultaneous treatments (alkali/ultrasound) promoted highly rough and porous Agave fibers (AF), which in conjunction with the processing conditions and the PP-g-MA improved the compatibility and interfacial adhesion with the PP. Moreover, DSC and XRD analysis showed an increase in the crystallization and melting temperature in the composites as the alkali/ultrasound treatment removed some lignocellulosic components of the fibers (hemicellulose, lignin, and waxes) and resulted in a highly structured material, which promoted the crystallization of the matrix and also acted as a nucleating agent. Furthermore, the fiber inclusion promoted a better interfacial stress transfer in the PP matrix, resulting in composites with low rigidity as revealed by the maximum stress and strain at break values. The alkali/ultrasound modified Agave fibers exhibited adequate structural performance to obtain flexible composites that can be useful to manufacture some automotive parts for the mobility sector.