ACETOSOLV SUGAR-CANE-BAGASSE LIGNIN IN THE SYNTHESIS OF PHENOLIC TYPERESINS

Phenolic type resin were prepared using lignin extracted by the acetos olv method (93% HOAc, 0.2% HCl, 6.8% H2O w/w; temperature: 107 degrees C; pulping time: 3 hours) from sugar-cane-bagasse, to be used as part ial substitute for resorcinol. The lignin was characterized in relatio n to: phenolic hydroxyl content (7%); Molecular weight (M (n) over bar = 830); Molecular weight distribution (M.W.D.). The pre-polymer was p repared using paraformaldehyde during the condensation reaction (alkal ine medium, 50 degrees C) and its M.W.D. compared with other sample pr epared without lignin. Both pre-polymers were crosslinked using parafo rmaldehyde and the obtained resins were characterized by Thermogravime tric Analysis (T.G.A.) and Differential Scanning Calorimetry (D.S.C.), leading to glass trasition temperature (Tg) values around 16O degrees C (resin with lignin) and 210 degrees C (resin without lignin).