## 3 Results and Discussion
### Morphological, Optical, and Physic-Mechanical Properties of Produced Handsheets
\begin{tabular}{c} **Grammage** \\ **(\(\mathbf{{}^{\text{*}}}\)m)** \\ \end{tabular}  & \begin{tabular}{c} **Thickness** \\ **(\(\upmu\)m)** \\ \end{tabular}  & \begin{tabular}{c} **Specific** \\ **(\(\mathbf{{}^{\text{*}}}\)m)** \\ \end{tabular}  & \ \begin{tabular}{c} **Specific** \\ **Volume** \\ **(\(\mathbf{{}^{\text{*}}}\)m)** \\ \end{tabular}  &
\begin{tabular}{c} **Gurley** \\ **300 cm\\\\\textPaper thicknesses (presented in Figures 17 and 18) were directly connected with air permeability properties, demonstrating that handsheets made from leaves or herbaceous matter presented higher Gurley times. Four tests performed with leaf matter had relatively high Gurley times in comparison with those analyzed from stem or bark matter. _Phylolaca americana_ leaf matter presented a Gurley time of 300 cm\({}^{3}\) in 43 s, whereas the tests run with stem matter were \(<\)1 s or 1.5 s, depending on pulp refining times. _Arundo donax_ leaves also presented higher Gurley times than stem matter, varying from 25.86 s (60 s PFI) or 34.86 s (120 s PFI) to 1.55 s (60 s PFI) or 2.1 s (120 s PFI). In the case of _Eucalyptus globulus_, as unique woody matter, it presented lower Gurley times for both leaves and bark matter (1.2 s; 2.9 s leaves and 1.3 s; 1.5 s bark). Figure 17: Thicknesses of handsheets elaborated from stem or bark raw matter in functions of different PFI (Test A; Test B; and Test C) times for four analyzed species. Figure 18: Thicknesses of handsheets elaborated from leaf raw matter in functions of different PFI (Test A; Test B; and Test C) times for four analyzed species. It is necessary to present the _Tradescantia fluminensis_ results as the most relevant in relation to air permeability. Due its morphological properties, this species demonstrated higher Gurley times with great differences, and also developed shorter PFI times (30 s), reducing yields in relation to the refinement of time properties. As shown in Table 4, _Tradescantia fluminensis_, for 30 s PFI refining time, presented a Gurley time of 262.3 s.  
The performed test demonstrated a relation between Schopper-Riegler refining degrees of pulp matter and Gurley time. It can be concluded that generally higher Schopper-Riegler degrees demonstrated higher Gurley times and smaller air permeability values in handsheets. The Schopper-Riegler test was designed to provide a measure of the rate at which a dilute suspension of pulp might be dewatered [39]. The relation of the drainability test is presented in Figure 19, and the relation of air permeability is presented in Figure 20. After running the test, it was concluded that Schopper-Riegler degrees higher than 72 were not possible to perform the handsheet test. It is the case for the test developed with _Phylolaca americana_ at more than 60 s at PFI, and for those performed with _Tradescantia fluminensis_ at 60 s and 120 s, that they were needed to reduce PFI times to 30 s.  
Figure 19: Drainability (\({}^{\circ}\)SR) in function of two different PFI (Test A; Test B) times for four analyzed species and matter (.h from leaves,.c for from bark, and.t from stems). Figure 20: Air permeability in (s) in function of two different PFI times (Test A; Test B) for four analyzed species and matter (.h from leaves,.c for from bark,.t from stems). Upon conducting a comprehensive examination of morphological characteristics, it becomes imperative to delve into the pulp properties, specifically focusing on drainability, to gain deeper insights into material behavior. Pulp derived from leaves exhibits elevated Schopper-Riegler (\({}^{\circ}\)SR) degrees when subjected to shorter PFI refining times. Typically characterized by shorter and finer fibers compared to those sourced from bark or other plant parts, this raw material historically contains a greater proportion of fines. Fines, being associated with larger surface areas, exhibit an enhanced capacity for swelling, resulting in quicker retention within the sieve of the Schopper-Riegler apparatus.