Effects of different emulsifiers on the bonding performance, freeze-thaw stability and retrogradation behavior of the resulting high amylose starch-based wood adhesive

Abstract High performance of starch-based wood adhesive is essentially important for its application in the versatile material science field. This study was carried out to evaluate the effect of different emulsifiers on the bonding performance, freeze-thaw (F/T) stability and retrogradation behavior of starch molecule in the adhesive system. The improved F/T stability and bonding performance was supported by the stability of viscosity after repeated F/T cycles and enhanced shear strength and grafting parameters. ζ- potential analysis revealed enhanced stability of the emulsion droplets through addition of emulsifiers. Furthermore, time sweep experiment, low-field nuclear magnetic resonance (LF-NMR), and x-ray diffraction (XRD) analysis showed that the retrogradation of starch molecule in the adhesive system was inhibited by addition of emulsifiers. Sodium dodecyl sulfate (SDS) showed the best improvement in the properties of high amylose starch-based wood adhesive (HASWA) among all the emulsifiers tested. These results offer a major step forward to prepare high performance bio-based wood adhesive in order to make them compete with less environment friendly wood adhesives.