Fast wood fiber esterification. I. Reaction with oxalic acid and cetyl alcohol

A method for modifying wood fiber with non-solvent media, to produce ready-to-use hydrophobic fiber suitable for use in composites, is proposed in this paper. The chemical modification was achieved by means of a consecutive reaction (cellulose/oxalic acid/cetyl alcohol) performed in a mixing chamber, at 110 °C and 30 rpm. The reaction product was washed by extraction with water and hexanes and then characterized by using spectroscopic techniques (FTIR and 13C CPMAS-NMR). The results from these analyses revealed the presence of CO groups, indicating that the esterification reaction was successful. The thermal stability of the treated samples was studied by thermogravimetric analysis (TGA); the modified fiber exhibited an increased thermal stability relative to the unmodified fiber, this increase may be related to both the formation of ester groups and the grafting of the cetyl radicals.