bioresources. com
PEER-REVIEWED BRIEF COMMUNICATION
size distribution ranges below 0.01 μm and a small number of pores between 0.2 and 0.5 μm. Regarding differential intrusion volume, all specimens presented values between approximately 0.20 and 0.90 mL/g. Table 2 shows the results obtained in the porosity tests. Table 2. Porosity Features of the Panels Porosity Features OSB 1 OSB 2 OSB 3 OSB 4 OSB 5 Total intrusion volume (mL/g) 0.492 0.756 0.752 0.312 0.330 Total pore area (m 2 /g) 8.66 22.91 32.30 33.71 11.15 Average pore diameter (μm) 0.227 0.132 0.093 0.037 0.119 Bulk density (mL/g) 0.716 0.724 0.724 1.079 0.910 Skeletal density (mL/g) 1.107 1.599 1.593 1.630 1.306 Porosity (%) 35.29 54.73 54.52 33.77 27.85 According to Bertolini et al. (2019), porosity of the panel is associated with voids between particles and with wood microstructural elements. Table 2 shows that OSB 2 and OSB 3, both filled with castor oil polyurethane resin and produced with Schizolobium amazonicum wood, exhibited the highest intruded mercury volumes and porosity values. OSB 1 and 4, both manufactured with Pinus sp ., showed similar porosity values, even though they were manufactured with different resin types and different resin content. However, OSB 4 presented a slightly lower value, which may be related to the higher density of the panel, as well as the higher amount of resin. OSB 5 had the lowest porosity value. In the other hand, the increase in the amount of resin from 10 (OSB 2) to 12% (OSB 3), both made with Schizolobium amazonicum , did not significantly influence the porosity performance of the panels. According to Vidaurre (2010), Schizolobium amazonicum species has a lumen diameter of about of 25. 6 μm. On the other hand, Corymbia citriodora and Pinus sp. had lumen diameters of about 5.4 μm and 27.84 μm, respectively (Amaral 2014; Segura 2015). However, it is important to highlight that the anatomy of wood of Corymbia citriodora and Pinus sp. is totally different, once the first one is hardwood and has fibriform fibers and vessels, whereas the second one is softwood and has tracheids cell. So, the anatomy characteristics of wood significantly contributed to the porosity results in OSB specimens. The OSB 4 and 5 specimens showed a total intrusion volume of 0.31 and 0.33 mL/g, respectively, but OSB 4 presented a greater percentage of porosity. This could be explained by the pore geometry (Fig. 2); when the pore is open and interconnected (c, d, e and f in Fig. 2), the mercury fills the space even before applying pressure (Santos et al. 2014).
Fig. 2. Representative scheme of pores with different sizes and shapes: (a) and (b) closed pores; (c) open pore; (d) and (e) interconnected pores; (f) surface roughness. (Santos et al. 2014)
6664
Ferro et al . (20 21). “Strandboard Hg porosimetry,” B io R esources 16(4), 6661-6668.
Made with FlippingBook Online document maker