Chemical modification of juvenile wood .1. Juvenility and response of southern pine OSB flakes to acetylation

A study was conducted to determine the influence of increasing juvenility on the response of loblolly pine OSB flakes to acetic anhydride treatment. The acetyl weight gains of OSB-type flakes from three different tree age classes (16, 25, and 34 yr.) and different stem locations (butt, middle, and top segments) were compared and analyzed. Acetylation was performed using a procedure similar to the dip-drain-and-heat acetylation method developed by Rowell et al. (15). Results indicate that the acetyl weight gain increases with increasing proportion of juvenile wood and increasing distance from the tree base, indicating that the more ''juvenile'' top portion of the stem responds better to acetic anhydride treatment. No significant differences in acetyl weight gain between the juvenile and mature flakes segregated on the basis of corewood-outer shell specific gravity profile were observed.