ENHANCEMENT OF MISCIBILITY BETWEEN HEMICELLULOSE AND LIGNIN BY ADDITION OF THEIR COPOLYMER, THE LIGNIN-CARBOHYDRATE COMPLEX

The miscibility between hemicellulose and lignin from beech wood was investigated from observation of their glass transition temperature, along with the effect of addition of their copolymer, the lignin-carbohydrate complex (LCC). The binary and ternary blend systems of hemicellulose, lignin and LCC change from immiscible to miscible by increasing the temperature. This behavior shows that this blend system has an upper critical solution temperature (UCST). The binodal temperature decreases with increasing amount of LCC added. This behavior was analyzed by the temperature and composition dependence of the Flory polymer-polymer interaction parameter (chi12). The value of chi12 estimated from the phase diagrams indicates that chi12 decreases with an increase in both the lignin content and the temperature.