Anthony J. Allen

Investigations of the Molecular Interactions of Soy-Based Adhesives

Formaldehyde-free wood adhesives based on combinations of soy flour and polyamidoamine-epichlorohydrin (PAE) resins are being used commercially. This combination has been shown to provide enhanced strength and water resistance compared with traditional soy-based adhesives. This study was undertaken to better understand the molecular interactions between a PAE resin and the various components of soy flour. PAE resins are cationic, water-soluble, thermosetting resins that contain high levels of azetidinium functionality. The main components of soy flour are protein (~50%), polysaccharides (15% to 25%), and soluble sugars (10% to 15%). Solid-state nuclear magnetic resonance spectroscopy (SSNMR) was used to study the molecular interactions occurring between soy flour components and a PAE resin. In these initial studies the efficiency of spin diffusion was observed and related to morphological differences between formulations comprising different ratios of PAE resin and soy flour. The thermal transitions of th...