## 3 Results  
### Characterization Results  
The results obtained in the tests of the tensile strength of the matrix and of the polymer/fiber composites (15, 20, and 25%) are shown in Figure 6a. A positive influence of the heenquen fiber was observed when mixing with the polymer, resulting in increments in the tensile strength where the highest value (24.2 MPa) was obtained with the composite containing 25% fiber. The increases are due, not only to the high mechanical strength of the heenquen fibers [38] when compared with other natural fibers [39], but also to the surface with an irregular texture that shows grooves in the longitudinal sense of the fibers. In addition, it is observed in Figure 7 that the resin occupies the recesses of the fiber, taking its shape, thus causing, besides the interfacial forces, a mechanical adherence that contributed to the increases in the tensile strength obtained. Increasing the percentage of bentonite in the polymer increases the tensile strength, as presented in Figure 6b. This increment is reversed for a 7% concentration of bentonite due to a partial agglomeration and non-homogeneous distribution of clay particles with an increasing charge concentration that is frequently observed in clay/polymer nanocomposites [36]. In the composites of polymer/bentonite, the clays were treated with quaternary ammonium salt, which allowed the partial exfoliation of the lamellae, provoking a good interaction and distribution between the polymer and the clay. This property manifests itself in the PoB5 composite, in which the best tensile strength result (30.3 MPa) was obtained with an increase of 89% in relation to the pure polymer. In the composite variant PoB7, the agglomeration of the mineral was partial, evidenced by a decrease in the tensile strength of the sample with respect to the PoB3 and PoB5 samples. The suspicion that the agglomeration was partial is corroborated by the fact that the sample with 7% of bentonite still has a greater tensile strength than that of the pure polymer. The addition of 15, 20, and 25% of fiber together with the addition of 5% organophilized bentonite reflects an increase in the tensile values with respect to the respective fiber/polymer compounds, but not with  
Figure 6: Tensile strength results. (**a**) Polymer/henequen composites (15, 20, and 25%); (**b**) polymer plus (3, 5, and 7%) of bentonite; (**c**) polymer plus 15% benequen and 5% of bentonite; polymer plus 20% benequen and 5% of bentonite; and polymer plus 25% benequen and 5% of bentonite. Figure 7: Composite with 15% fiber after tensile test, 350\(\times\), bas corresponds to 100 \(\upmu\)m.  
respect to the combination clay/polymer in which case their values were greater except for the PoH25 sample, as shown in Figure 6c. The presence of the fiber did not provide a substantial synergistic effect when in the presence of 5% bentonite. This fact can be explained by the appearance of voids in the polymer matrix as seen in the micrographs of Figure 8. These pores of spherical morphology may have been formed by the difficulty in expelling the air caused by the increase in the viscosity of the resin containing clay in the presence of the fibers, in the step of pressing the mold. Figure 9 shows the transmission electron micrographs of the composite containing 25% fiber and 5%, bentonite (PoB5H25). Observed in Figure 9a are regions where the clay particles are intercalated with polymer and others where the delaminated clay particles (spheres) appear tenuously with a diaphanous appearance, being partially transparent to the electrons, due to their nanometric thickness with little or no stacking. In Figure 9b, regions with interspersed particles and others with particles exfoliated to a greater or lesser degree are observed. Thus, both XRD and TEM, results show that intercalated, partially exfoliated nanocomposites were obtained.