Abstract: A single-component polyurethane adhesive for bonding wood curable at room temperature under moist condition was synthesized from methylene-bridged polyphenylene polyisocyanate (PAPI) and polyether polyol. Effects of chemical constituents on mechanical properties of adhesive were studied.The results showed that press shearing strength of poplarwood (Populus×euramericana cv.) board bonded with this adhesive was 60% higher than that with MDI.Using polyethere oxide diols(PED)of relative molecular weight(M_W) 800,1000 and 2000,with polypropylene oxide triols of M_W 300 and 3000(N303 and N330),and polytetramethylene ether glycol-propylene oxide diol(NG220),at optimal ratio, catalyzed by compounded catalyst of modified amine and organic stannum, dry and wet press shearing strengths and curing speed of the adhesion could be efficiently incresed, especially wet wood failure could reach 100% and 90% for bonding poplarwood and oakwood respectively. The formation of —NHCOO— between hydroxyl groups of polyol and isocyanate groups of PAPI was verified by FT-IR spectroscopy.

Key words: polyurethane, wood adhesive