Dimensional changes in Corsican pine sapwood due to chemical modification with linear chain anhydrides

The volumetric changes in Corsican pine sapwood due to modification with an homologous series of linear chain anhydrides has been studied. The results have been interpreted in terms of the molar volume occupied by the substituent groups in the wood cell wall. At low levels of substitution, the molar volume is larger at low weight gains. Thus if the volume increase is due to a volume occupied by the reagent molecules and a void volume created within the wood matrix, then the void volume is lar er at low levels of substitution. A non-linear relationship has also been found between the void volume and volume occupied by adduct as the size of the anhydride increases. By determining the relationship between average molar volume at high weight gains and ultimate level of OH substitution, for the range of anhydrides studied, it is possible to estimate the number of accessible OH groups at 5.7 (+/- 0.4) mMoles/gm, this contrasts with a theoretically calculated value of 8.6 mMoles/gm.