Toward high performance renewable agave reinforced biocomposites: Optimization of fiber performance and fiber-matrix adhesion analysis

The increasing sensitivity toward the environmental pollution and the recent laws on the environmental protection, have led to an increasing attention to the so called biocomposites, i.e. to ecofriendly or renewable composite materials, obtained from biopolymers reinforced by natural fibers. Although the contribution of various works reported in literature, focused on biocomposites reinforced by agave fibers, such materials are still exclusively used in the automotive industry for non-structural applications, and the implementation of high performance biocomposites for semi-structural and structural applications, is an expected, but not yet reached objective. Therefore, the present work aims to give a contribution to reach such an objective, by means of a proper selection of the fiber, in terms of variety, age and position, as well as by the implementation of a new ecofriendly fiber extraction method that allows the user to obtain fibers with improved mechanical performance. In more detail, it is shown that the agave marginata, widespread in the Mediterranean area, provides fiber with performance higher than the agave sisalana commonly considered in literature, and its performance can be furtherly improved by proper optimization of the main influence parameters and the extraction process. On the basis of these optimized fibers, as well as of thermoplastic and thermosetting matrixes, particularly suitable for the manufacturing of high performance ecofriendly biocomposites, an accurate theoretical-experimental analysis on the fiber-matrix adhesion has allowed first to confirm the good adhesion of the agave with epoxy and PLA matrixes, as well as to detect the actual influence of the mercerization treatments and the significant effects of the stiffness of the coupled materials on the potential pull-out and/or debonding damage mechanisms.