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PEER-REVIEWED ARTICLE
According to Table 1, the air-dry density values of treated samples ranged from 0.620 to 0.665 g/cm 3 . The panels that were manufactured with different ratios of WPE had similar density values. Moisture content values decreased due to increasing WPE amount; similarly, dimensional change values decreased significantly based on increasing WPE amount compared to the control samples. Hydroxyl groups in treated OSB decreased with an increase of WPE amount, thus improving the dimensional change stability. For wood, dimensional changes are commonly assumed to be linearly related to changes in moisture content (Zelinka and Glass 2010). The highest moisture content was obtained (5.79%) from the non-WPE sample, and the lowest value was obtained (3.34%) from the sample with 50% WPE. The physical and mechanical properties of wood materials, such as MOE, MOR, IB, etc. , are affected greatly by moisture content (MC) (Niemz 2010). In this study, dimensional changes after 24 and 48 h were considerably lower than the control values. The greatest dimensional change after 24 h was obtained (0.59%) from the untreated sample, and the lowest value after 24 h was obtained (0.17%) from the sample with 50% WPE parallel to the grain. The greatest dimensional change after 48 h was 0.98% in the untreated sample, and the lowest value of DC after 48 h was 0.12% in the sample with 50% WPE perpendicular to grain. According to these results, using polyethylene in OSB affected the MC value positively. The DC value was also positively affected because of the decrease in MC value. In wood and wood-based materials, swelling occurs because of absorbed water and shrinkage occurs when the absorbed water is released (Niemz 2010). Thickness Swelling and Water Absorption Average and standard deviation values of thickness swelling (TS) and water absorption (WA) of treated OSB panels are shown in Table 2. Table 2. Average Values of Thickness Swelling and Water Absorption Rate in the OSB Panels Produced by Adding WPE in Various Ratios Wood Polyethylene TS (%) WA (%) % % 24 h 48 h 24 h 48 h 100 ------- 27.46 (4.84) A [1] 28.85 (5.15) A [1] 65.78 (8.81) A 70.97 (8.25) A 90 10 26.32 (4.06) A [1] 28.06 (5.36) A [1] 64.49 (11.95) A 69.93 (10.20) AB 80 20 19.24 (4.40) B [2] 22.08 (3.50) B [2] 53.74 (6.24) B 60.39 (8.32) B 70 30 13.65 (4.34) C [3] 16.96 (4.23) C [3] 45.43 (5.94) C 50.01 (6.18) C 60 40 8.84 (3.61) D [4] 12.75 (4.67) CD [3] 31.68 (8.50) D 35.35 (8.06) D 50 50 8.11 (3.08) D [4] 9.58 (4.26) D [4] 22.47 (6.65) E 23.97 (5.37) E *Groups with the same letters in each column indicate that there is no statistical difference (pr < 0.05) between the samples according to the Duncan’s multiple range test . *Data were statistically analyzed by means of average and standard deviation. *Quality requirements were compared to OSB type 1-2-3-4 (EN 300 OSB minimum property requirement 2006) and are notated in brackets. Both 24 and 48 h thickness swelling values were considerably lower than the control values. The highest value of TS after 24 h was 27.46% in the non-WPE panel sample, of TS after 48 h was 28.85% in the non-WPE sample, and the lowest value of TS after and the lowest value of TS after 24 h was 8.11% in the sample with 50% WPE. The highest value 48 h was 9.58% in the sample with 50% WPE. According to Table 2, minor differences were obtained between 24 h and 48 h TS values but as seen, the variance from
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Yorur (2016 ). “Waste PE and effects on OSB,” B io R esources 11(1), 2483-2491.
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