Dimensional stability of OSB made from acetylated Fir strands

Picea abies

) ring-cut strands were acetylated by reaction with acetic anhydride at 120 °C for periods of 30 and 60 minutes. The results indicated a weight gain of 11.2% and 20.4% respectively. Treated and untreated strands were used to form laboratory boards, which were tested in accordance with EN standards. Boards made from these acetylated strands exhibited significantly lower thickness swelling and water absorption when compared with the control. The internal bond strength (IBS) of test boards was significantly lowere (−19%), but still within International standards, than the control boards, and failure was due to resin bond failure. This would suggest that lower resin dosing could partially offset acetylation costs in industrially produced boards. Finally, we observed that boards made with acetylated strands were less compressible than the control boards.