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PEER-REVIEWED ARTICLE
boards met the requirements for OSB/3, and EE boards matched OSB/4 standards. All manufactured boards had a very high internal bond, similar to the industrial boards. They also showed relatively low thickness swelling, considering the fact that no water resistance improving agents were used during manufacturing. Moreover, an analysis of the group homogeneity for the experimental boards demonstrated a much lower variability of their shorter axis properties, particularly regarding the modulus of elasticity. This was probably due to the fact that their core layer was made of the same type of strand chips arranged along the longer axis of a sample, thereby stabilizing their properties for transverse direction. In manufactured OSB, a linear relationship with chip length was observed only for modulus of rigidity (Fig. 2). The equation for modulus of rigidity (MORII = 0.2884L + 13.005) was characterized by a high coefficient of fit (R 2 ) amounting to 0.9988. Large length differences in the individual types of chips, particularly between AA and EE chips made the coefficient trend towards a linear relationship (Anscombe's quartet). The other parameters investigated during the bend test fell into two intervals, depending on chip length. The first interval featured a strong increase of a specific value and comprised chips from 4.2 mm to 15.1 mm long, and the second interval included chips from 15.1 mm to 96.8 mm long belonging to CC and EE groups in which the parameter increase was slower.
4.2 10.2 15.1
49.6
96.8
10 15 20 25 30 35 40 45
7000
MOR II MOE II MOR A MOE A
6000
5000
4000
3000
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1000
4.2 10.2 15.1
49.6
96.8
Length [mm]
Fig. 2. Effect of the mean (weighted) average length of the chips on the static bending strength and modulus of elasticity Even though the length of the chips within individual groups showed a high variability of linear dimensions, the obtained values fit the relationships described by Barnes (2000) (Fig. 2). The quality of the chip orientation in the individual layers of OSB was essential for MOR and MOE for specific board axis. The better the orientation was, the higher the orientation index. For OSB the expected orientation index is 2, and for the MFP panels it should be as close as possible to 1. Both industrial boards met the relevant requirements, and the lowest values of the investigated parameters for the laboratory- manufactured boards were observed in those made from CC and DD chips. Therefore, they may serve as an alternative for MFP boards, as their properties were also similar to the requirements of EN 312 (2010).
8349
Mirski et al . (2016). “Non - strand chips OSB,” B io R esources 11(4), 8344-8354.
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