B-11 magnetic resonance imaging and MAS spectroscopy of trimethylborate-treated radiata pine wood

Boron-11 nuclear magnetic resonance imaging and spectroscopy have been used to characterise the nature and distribution of boron compounds after prese rvative treatment of radiata pine wood with trimethylborate (TMB). One day after treatment, B-11 magnetic resonance imaging microscopy showed signific ant differences in the morphological distribution of boron species, with th ere apparently being no treatment penetration of the latewood. B-11 MAS NMR spectroscopy of freshly preservative-treated radiata pine wood, which had been separated into latewood and earlywood, showed the only boron species p resent in the latewood to be boric acid while in the earlywood both TMB and boric acid were initially present. Due to quadrupolar broadening and a sho rt T-2 value, the boric acid signal relaxed too quickly to be observable an d this caused the apparent lack of B-11 in the image when only boric acid w as present. TMB undergoes hydrolysis to form boric acid and in radiata pine latewood, this hydrolysis reaction is rapid. (C) 1999 Elsevier Science B.V . All rights reserved.