Abstract:

The bonding reactions of isocyanate resin to wood are composed of those that isocyanate group reacted with lignin， semicellulose，cellulose and water．As a result，the knowledge about reaction of isocyanate group with each wood component does well to understand and to control wood bonding with isocyanate resin．Therfore，the paper mainly studied on the reactions between the phenyl isocyanate (BMI) and lignin，cellulose，wood powder by the differential scanning calorimetry (DSC) technique．In different calefactive rates，it characterized the reactions of isocyanate with lignin，wood powder，respectively，with two moisture contents(MC) which were absolute dry moisture content(MC=0%) and equilibrium moisture content (MC：3% for lignin，and 5% for wood powder)．It also evaluated the reactions characterizations of isocyanate with the mixtures of lignin and cellulose with different weight ratios．Based on the analyses to the DSC curves and Ozawa equation，the activation energies of the reactions of the BMI-lignin，BMI-wood powder were obtained，by which the reaction characterizations of the phenylisocyanate with lignin，cellulose，and wood powder are discussed．The study indicated that the reaction temperature and activated energy of BMI-lignin system were lower than those of BMI-wood system．The BMI mainly reacts with lignin when cellulose and lignin were mixed together．However，the reaction degree of BMl with cellulose increased with the cellulose content increasing in cellulose-lignin mixture．When the moisture content of wood reached 5%．The reaction activation of BMI-wood system reduced34%．

Key words: isocyanate, lignin, cellulose, wood, differential scanning calorimetry