Anisotropic physical and mechanical performance of pf-impregnated oriented strand board
Journal
BioResources
Journal Volume
8
Journal Issue
2
Pages
1933-1945
Date Issued
2013
Author(s)
Abstract
This study investigated several key mechanical and physical properties of oriented strand board (OSB) made from China fir strands impregnated with phenol-formaldehyde (PF) resin.Results showed that accumulated percentages of strand alignment angles between strand length direction and mechanical alignment direction on OSB face and bottom layer were within 0° and 30° vs. 88.2% and 76.2%, respectively.Ultrasonic velocity at 0° strand angle (V 0 ) was the highest, decreasing rapidly with increasing aligned angle (θ).The lowest ultrasonic velocity was found at 90° of strand's angle (V 90 ).The relationship between θ and V could be represented by Hankinson's formula, where the optimal n exponential values were between 1.59 and 1.88.The anisotropic properties of the OSBs, defined as the ratio of V 0 /V 90 , were 2.23 to 2.45 for the bending specimens.The ratios of MOR p /MOR v and MOE p /MOE v were 3.79 to 4.15 and 4.18 to 5.42, respectively.Effects of PF-impregnation on the bending properties showed superior performance.The parallel bending strength (MOR p ) was 64.7 to 84.8 MPa and the MOE p was 13.0 to 15.9 GPa, respectively.After accelerated deterioration testing, the retention rates of MOR p and MOE p (%) were 78.3% to 88.2% and 68.0 to 83.1%, respectively.Further, the dimensional stability of PF-impregnated OSB showed good performance in thickness swelling (TS) and linear expansion (LE).
Type
journal article