Study On Modification Mechanism And Methods For Natural And Mineral Materials For Wood Adhesive Resins

Environment-friendly tannin/lignin, soy protein-based wood adhesive, gluten protein-based adhesive were studied. The feasibility and mechanism to use non-toxic, non-volatile glyoxal to substitute toxic, volatile formaldehyde in relevant formulations was analyzed. The suitable addition percentage was determined. The lab-prepared particleboard procedure was optimized too.The results shown in this work confirmed few aspects of these formulations, namely:(1) The performance of these formulations is determined to a great degree by the amount or proportion of the pMDI used. Lignin-based adhesives and glyoxalated soy-based wood adhesives mixed with pMDI and mimosa tannin satisfying the requirements of relevant international standards for the manufacture of wood particleboard were obtained.(2) The IB strength results of boards bonded with the heat-treated are worse than when using the original lignin itself.(3) The particleboard strength with formulations based on glyoxalated soy was better than that with glyoxalated lignin.(4) The reaction between lignin and glyoxal occurred.Some work has been done on the study of the influence of nano-montmorillonite (MMT) on urea-formaldehyde resin and phenolic resin adhesives. The level of exfoliation of the MMT being mixed with these resins was determined by X-ray powder analysis. The thermal and mechanical characteristics of the mixed system were studied. Some conclusions can be drawn.(1) Na montmorillonite (Na-MMT) is completely exfoliated when mixed with UF resins, while it only has some degree of intercalation when added to PF and PUF resins.(2) The addition of Na-MMT affected the curing of UF and phenolic resins. The addition of small percentages of Na-MMT does not appear to improve much the resins dry performance, while it seems to increase the water resistance of the UF-bonded and phenolic-bond panels. Na-MMT could decrease the formaldehyde emission of particleboard, too. Both dry strength and wet strength performance with Na-MMT as fillers were better than those with wheat flour.