## 3 Results and Discussion
### Mechanical Properties of Green Composites
\begin{table}
\begin{tabular}{l c c c} \hline \hline
**Film** & **T\({}_{\rm onset}\)**(\({}^{\circ}\)**C**) & **T\({}_{\rm deg}\)**(\({}^{\circ}\)**C**) & **Residual Mass (\%)** \\ \hline PHBV & 277.50 \(\pm\) 1.54 \({}^{\rm a}\) & 296.25 \(\pm\) 0.59 \({}^{\rm a}\) & 2.26 \(\pm\) 0.04 \({}^{\rm a}\) \\ PHBV\_25\%MFC & 280.42 \(\pm\) 1.77 \({}^{\rm b}\) & 301.67 \(\pm\) 1.18 \({}^{\rm b}\) & 2.76 \(\pm\) 0.12 \({}^{\rm a}\) \\ PHBV\_59\%MFC & 282.92 \(\pm\) 1.12 \({}^{\rm b}\) & 301.67 \(\pm\) 1.71 \({}^{\rm b}\) & 2.07 \(\pm\) 0.57 \({}^{\rm a}\) \\ PHBV\_10\%MFC & 288.75 \(\pm\) 2.95 \({}^{\rm c}\) & 305.83 \(\pm\) 2.47 \({}^{\rm c}\) & 1.91 \(\pm\) 0.84 \({}^{\rm a}\) \\ PHBV\_ESAO & 227.08 \(\pm\) 3.23 \({}^{\rm d}\) & 255.00 \(\pm\) 2.46 \({}^{\rm d}\) & 2.02 \(\pm\) 0.08 \({}^{\rm a}\) \\ PHBV\_ TGIC+DCP & 256.25 \(\pm\) 1.27 \({}^{\rm e}\) & 276.67 \(\pm\) 2.39 \({}^{\rm e}\) & 2.11 \(\pm\) 0.15 \({}^{\rm a}\) \\ PHBV\_59\%MFC\_ESAO & 274.17 \(\pm\) 2.35 \({}^{\rm a}\) & 296.67 \(\pm\) 1.18 \({}^{\rm d}\) & 2.16 \(\pm\) 0.69 \({}^{\rm a}\) \\ PHBV\_59\%MFC\_TGIC+DCP & 277.08 \(\pm\) 0.59 \({}^{\rm a}\) & 300.83 \(\pm\) 1.17 \({}^{\rm d}\) & 2.01 \(\pm\) 0.11 \({}^{\rm a}\) \\ \hline \hline \end{tabular}  
\(T_{\rm onset}\) = onset degradation temperature (measured at 5% mass loss); T\({}_{\rm deg}\) = degradation temperature. Mean values and standard deviation. *+ Different superscripts in the same column indicate significant differences between formulations (\(p<0.05\)).  
\end{table} 
Table 4: Thermal properties obtained by thermogravimetric analysis (TGA) of the films of poly(3-hydroxyrate-_co_-3-hydroxyvalerate) (PHBV) with microfibrillated cellulose (MFC) and compatibilized with epoxy-based styrene-acrylic oligomer (ESAO) and with triglycidyl isocyanate (TGIC) and dicumyl peroxide (DCP). respectively. A slight increase in the mechanical strength was also observed, reaching \(\sigma_{y}\) values of 27.8 MPa and 29.3 MPa. Furthermore, in the case of ductility, the composite films that were processed with ESAO and with TGIC and DCP yielded values of 0.9% and 1.4%, being the latter significantly higher (\(p<0.05\)) than that of the uncompatibilized PHBV/MFC composite. Moreover, for the PHBV composite samples that were processed with TGIC and DCP, the samples were slightly more deformable than the neat PHBV film, but still not significant (\(p>0.05\)). The results attained herein confirm the improvement that was achieved in the PHA composite samples with MFC compatibilized by means of these two multi-functional agents, that is, with multiple reactive groups in their chemical structure that are capable of interacting through covalent bonds favoring the grafting of reinforcing fillers onto the biopolymer matrix [34, 35]. The positive effect on the mechanical strength provided by the cellulose microstructures obtained by atomization is also noteworthy, even without the use of compatibilizers. Thus, the incorporation of MFC provided higher mechanical strength to PHBV, with a relatively low impairment in ductility, due to their high degree of dispersion and micrometric size. Figure 11: Stress (\(\sigma\)) versus strain (\(\epsilon\)) curves of the films of poly(3-hydroxybutyrate-\(co\)-3-hydroxyvalerate) (PHBV) with microfbilitated cellulose (MFC) and compatibilized with epoxy-based styrene-acrylic oligomer (ESAO) and with triglyceride l isocyanurate (TGIC) and dicumyl peroxide (DCP).