Preparation of Wood Adhesives from the Rice Powder and pMDIs;

To investigate the adhesion effect of various kinds and contents of polymeric methylene diphenyl diisocyanates (pMDIs) on adhesion performance, wood adhesives (A-1~5) were synthesized and characterized. As results, when the amount of pMDI increased in adhesives, the dry tensile strength was found to be proportionally increased sustaining at around 16.0~21.6 kgf/cm2. The polyurethane (PU) resin, which used M11S as a source of pMDI showed the best wet tensile strength at 11.9 kgf/cm2 and cyclic boil tensile strength at 8.1 kgf/cm2, which satisfied the requirement of over 7 kgf/cm2. Thermal properties of the rice powder (RP) based polyurethane resins were characterized by differential scanning calorimetry (DSC) and Thermal gravimetric analysis (TGA). Thermal stability of polyurethane resins increased to 250℃ with adding pMDIs. The more pMDI (M5S) was added to adhesive, the higher thermal stability of the resin was observed by TGA.