New Concept in Bioderived Composites: Biochar as Toughening Agent for Improving Performances and Durability of Agave-Based Epoxy Biocomposites

Abstract

Biocomposites are increasingly used in the industry for the replacement of synthetic materials, thanks to their good mechanical properties, being lightweight, and having low cost. Unfortunately, in several potential fields of structural application their static strength and fatigue life are not high enough. For this reason, several chemical treatments on the fibers have been proposed in literature, although still without fully satisfactory results. To overcome this drawback, in this study we present a procedure based on the addition of a carbonaceous filler to a green epoxy matrix reinforced by Agave sisalana fibers. Among all carbon-based materials, biochar was selected for its environmental friendliness, along with its ability to improve the mechanical properties of polymers. Different percentages of biochar, 1, 2, and 4 wt %, were finely dispersed into the resin using a mixer and a sonicator, then a compression molding process coupled with an optimized thermomechanical cure process was used to produce a short fiber biocomposite with Vf = 35%. Systematic experimental tests have shown that the presence of biochar, in the amount 2 wt %, has significant effects on the matrix and fiber interphase, and leads to an increase of up to three orders of magnitude in the fatigue life, together with an appreciable improvement in static tensile strength.

Basalt Fiber Hybridization Effects on High-Performance Sisal-Reinforced Biocomposites

“…The matrix used for both biocomposites considered was a green epoxy produced by the American Entropy Resin Inc. (San Antonio, CA, USA), named SUPERSAP CNR, with IHN-type hardener [ 28 ]. As widely shown in previous studies [ 24 , 25 , 26 , 27 ] by the same authors, this matrix exhibits an almost linear elastic behavior with density ρ m = 1.05 g/cm 3 , tensile strength σ m , R 50 MPa, Young modulus E m ≅ 2.7 GPa, and tensile fracture strain ε m , R ≅ 2.5% (see also Table 1 ).…”

“…In detail, the sisal fabrics, that are not disposable in the current market, were obtained by manual stretching of the fibers in order to eliminate natural undulations; alignment of the straight fibers arranged into small groups, the transversal stitching by using an automatic machine (see Figure 1 b). These unidirectional fabrics, also used to manufacture the pure sisal cross-ply biocomposites (SFRP) considered to compare the performance of the B-FSRP, were the same as those already used in several previous studies by the same authors [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ].…”

Recent Advances in Biochar Polymer Composites

“…Zuccarello et al [127] reported an increase of ultimate tensile stress and strain by about 55% and 250%, respectively, by adding 2 wt.% BC obtained from Mischantus pyrolyzed at 550 • C to agave epoxy composites. Nonetheless, the greatest improvements were achieved considering the specific failure energy fatigue life performance that became 5 times and 3 orders of magnitude bigger with respect to the composites without BC.…”

Sustainable Materials Containing Biochar Particles: A Review

“…A noticeable improvement in mechanical properties has been obtained by introducing a suitable concentration of biochar particles in eco-friendly bio-composites manufactured by a green epoxy matrix reinforced with short agave fibers for replacing synthetic materials in structural applications [ 83 ]. In that case, with the optimum amount of BC particles (in this case found to be equal to 2 wt.%) added by means of the synergic effect of short fiber and biochar particles, a better adhesion has been achieved between the epoxy matrix and fiber, which was demonstrated by the fiber pull-out test.…”