THE THERMAL-BEHAVIOR OF LIGNINS FROM WASTED BLACK PULPING LIQUORS

The thermal degradation of lignins separated from black liquor waste f rom pulping of bagasse and cotton stalks has been investigated. Therma l gravimetric analysis (TGA), differential thermal analysis (DTA) and derivative thermogravimetry (DTG), between 20 and 1000-degrees-C, have been used. Activation energies of treated lignins were calculated. Li gnins separated from liquors obtained at low pulping temperature have higher activation energies than high-temperature lignins. The use of a nthraquinone (AQ) as an additive for accelerating the pulping process raises the activation energy of the lignin in the black liquors waste.