In this study, to reinforce aqueous vinyl polymer solution-isocyanate adhesives（ APIs）, we mixed cellulose nanofibers（ CNFs） with two types of polyvinyl alcohol（ PVA） having different degrees of saponification and polymeric diphenylmethane diisocyanate（ pMDI） content. These adhesive mixtures were evaluated by scan ning electron microscopy（ SEM）, and their dynamic viscoelasticity, moisture absorptivity, water dissolution rate, and wood- bonding performance under compressive shear were analyzed. The partially saponified PVA showed a higher CNF reinforcement effect than the completely saponified PVA, and CNF reinforcement de creased with increasing pMDI content. In terms of dynamic viscoelasticity, the storage modulus（ E’） and loss modulus（ E’’） both were inhibited decreasing in the rubbery region above the glass transition temperature. Moisture absorptivity and water dissolution rate decreased as CNF content increased, but decreased as pMDI content increased. In contrast, wood-bonding performance declined as CNF content increased, irrespective of saponification degree and pMDI content.
