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272 N.M. Garz on-Barrero et al. / International Biodeterioration & Biodegradation 115 (2016) 266e276
3.2.2. Longitudinal analysis of fungal growth e in accelerated test During the first 7 days of exposure, the mold colonization pro-
(ASTM D 3273-12, 2012) cess began on the surface of uncoated test samples of the two
In Table 4 the estimated probabilities results are presented for materials (ncMDP and ncBCP). The sugarcane (ncBCP) and wood
fungal growth and colonization. The test samples of sugarcane (ncMDP) particle boards had a 70% probability of presenting on the
bagasse (BCP) and of wood (MDP) presented similar degrees of evaluation scale a value less than 4. The estimated probabilities of
colonization, and colonization was reduced by the presence of total colonization (a grade equal to 0) by fungi at the end of the 28
surface coating on these test samples. days of exposure were 95% (for ncMDP) and 94% (for ncBCP)
The probabilities of coated test samples were estimated at 9% for respectively.
cBCP and 10% cMDP for presenting a note of 9 on the evaluation Table 5 presents the probability estimates obtained for mold
scale of surface growth in the first 7 days. In the coated test samples growth, analyzing the effects of surface coating and incubation
of cMDP and cBCP low colonization grades for mold were main- time. It was observed in the first 7 days of exposure, an important
tained during the first 21 days of exposure. After 28 days the test influence in the presence of coating with castor oil based poly-
samples of cMDP and cBCP presented a grade of 9 and probabilities urethane resin.
of 70% and 73% respectively. This is attributed to the protecting The degree of colonization between the beginning of the incu-
effect of the castor oil based polyurethane resin which limited the bation and the end of the experiment was low for the test samples
fungi attack on the materials. coated with castor oil based polyurethane resin with 90%

Table 4
Probabilities of colonization for the sugarcane particle boards (BCP) and wood particle boards (MDP) in the interactions between material, coating and incubation time for the
accelerated mold growth test (ASTM D3273-2012).