Page 9 - Test e-book yru envi

274 N.M. Garz on-Barrero et al. / International Biodeterioration & Biodegradation 115 (2016) 266e276

Fig. 5. SEM Images. a) and b) Non-coated sugarcane bagasse particle boards (ncBCP) before and after the 28-days accelerated aging test. c) and d) Non-coated medium density wood
particle boards (ncMDP) before and after the 28-days accelerated aging test.

Table 6
Mechanical and physical properties of sugarcane bagasse particle board (BCP) and medium density wood particle board (MDP) before and after exposition to accelerated aging
test and natural weathering (ASTM D 3273-12, 2012).
Properties Material Surface coating Non-aged Accelerated test (28 days) Natural exposure (12 months)
Modulus of Elasticity (GPa) BCP Non-coated 2.07 0.32 0.31
BCP Coated 2.15 0.66 0.38
MDP Non-coated 2.52 0.20 0.05
MDP Coated 2.73 0.49 0.11
Standard error 0.10 0.03 0.02
Modulus of Rupture (MPa) BCP Non-coated 17.9 4.2 3.5
BCP Coated 21.7 7.7 7.5
MDP Non-coated 15.6 1.4 0.5
MDP Coated 20.7 3.6 1.6
Standard error 1.2 0.3 0.2
Thickness swelling (%) BCP Non-coated e 49.5 39.9
BCP Coated e 26.9 26.1
MDP Non-coated e 49.8 56.0
MDP Coated e 34.8 62.2
Standard error e 3.5 4.9

boards exposed during 12 months in Japan (5.36 MPa). In the interface and the coating. This is due to degradation agents present
present study the commercial MDP wood boards reached values of in natural exposure (water in form of humidity and precipitation,
1.6 MPa for cMDP and 0.5 MPa for ncMDP, being therefore inferior temperature) having possibly been the cause of tensions between
results in comparison to those indicated by the previously referred the surface coating and the interface on the outer layers of the
author. specimens due to their multilayer configuration, unlike the
Finally, after one year of exposure to natural weathering the monolayer configuration of panels made of sugarcane bagasse
specimens corresponding to the coated (cMDP) and non-coated (BCP).
(ncMDP) commercial panels of eucalyptus wood particles pre-
sented similar behavior to each other with over 50% of thickness
swelling. Petri c et al. (2007) indicated that excessive moisture may 4. Conclusions
have consequences on the dimensional stability of the material
resulting in the development of tensions between the wood Both materials, sugarcane bagasse (BCP) and commercial wood
particle boards (MDP) without superficial treatment, presented