Evaluation of glycolaldehyde as a formaldehyde substitute in urea-based wood adhesives

Abstract

Glycolaldehyde, produced from cracking of glucose, was tested as a substitute for formaldehyde in urea-based wood adhesives. Initially, different parameters (water content, aldehyde/urea-ratio, curing temperature, and time) were screened to identify the optimal curing conditions providing the highest bond strength. Afterwards, the system was reformulated as a 2-component system and compared to a urea-formaldehyde 2-component system, which showed a comparatively low strength of the resulting resin. Different hardeners were tested, and AlCl3 showed an 80% increase in bond strength for the resin compared to NH4Cl. Infrared and nuclear magnetic resonance analyses were performed to ensure formation of the desired aminal bond network, which showed that the hardener was essential for proper curing of the resin. Finally, a urea-glycolaldehyde-formaldehyde resin was tested that further indicated major differences between the reactivity of formaldehyde and glycolaldehyde.

Formation mechanism of wood rotary welding interface by various additives

“…The main thermal cleavage products of group CA were Glycolaldehyde is also a major product of the rapid pyrolysis of cellulose (Piskorz et al 198 6); the main source of glycolaldehyde dimers in the CA group may be the decomposition of 1,6-a nhydro β-D-glucopyranose with the polymerization of glycolaldehyde monomers, and the production of glycolaldehyde dimers during the welding process may have increased the adhesion of the woo d fusion system to form a biobased adhesive (GA) containing glycolaldehyde; Formaldehyde is curr ently used in a variety of adhesives for wood construction materials, which releases a certain amou nt of free formaldehyde, and with the use of GA, the release of free formaldehyde decreases due t o the reduction of the vapor pressure of GA (Sandahl et al 2022), which also avoids to a certain extent the pollution of the environment from the rotary welding of wood to produce adhesive sub stances in daily use. The formation mechanism of the wood rotary welding interface was found by SEM, FTIR, X RD, and Py-GC/MS tests:…”

Underwater Bonding with a Biobased Adhesive from Tannic Acid and Zein Protein

“…Once the in vivo and biomedical realm is left behind, there is an entire world of other applications requiring metals, plastics, wood, and inorganic substrates that need adhesives to work in the presence of water. − Food, oral, and cosmetic applications are less restrictive when it comes to purity of starting materials. Food-grade polymers can often be used for making wet adhesives .…”