The incorporation of corn- and soybean-based materials into plywood adhesives

A cornstarch-derived mixed methyl glucoside product, Sta-Meg{dollar}spcircler{dollar} 100 (MeG) and soy molasses demonstrated potential as effective extenders in phenolic resol resin-based adhesives used for bonding southern yellow pine into exterior grade plywood. Soy protein products showed modest potential.; By replacing up to 25% of extended glue mixes with MeG or replacing 12% of resin solids, adhesive performance matched or surpassed controls. An array of MeG modified resins was synthesized from 2.1-2.7 F/P (formaldehyde/phenol) and 5-20% MeG as resin solids replacement. By co-increasing MeG and F/P, resins with control-like properties were synthesized up to maximum modification. All resins performed well in extended glues, bonding 8% moisture (m.c.) veneer with 60 minute assembly. With 15 minute assembly, controls were undercured, but co-increasing MeG and F/P restored performance. Resins were synthesized with 35% and 50% MeG as phenol replacement in 1.7 and 2.1 F/P control formulations, by increasing reaction temperatures 5{dollar}spcirc{lcub}-{rcub}10spcirc{dollar}C. Gel time and free formaldehyde were comparable to controls. All glue mixes performed well at full cure with 9% m.c. veneer. At reduced hot press, MeG-modification accelerated cure, with a 35% optimum.; Soy whey, soy molasses, defatted soy flour, soy protein concentrate, soy protein isolate, and spent soy hulls were screened as 10% replacement of resin binder polymer in extended glues on 7.5% m.c. veneer. None of the glues matched control, but hulls performed best. Flour, concentrate, and isolate showed some adhesive ability. Whey and molasses performed like fillers. Molasses, flour, concentrate, and isolate, were synthesized into resins as 10% phenol replacement. Resins were similar to controls except for thixotropy and reduced formaldehyde of molasses resin. In bonding moist veneers, molasses resins accelerated cure, while maintaining full cure performance. Isolate accelerated wet strength development. A series of phenol replacement molasses-modified resins was prepared to 50%. Resins had increasing solids and decreasing free formaldehyde to 40% SM, with peculiar thixotropyldose response. Molasses resins showed cure acceleration over 10-30% range, but full cure bonding fell at 30%.