Researchers Find New Glucose and Citric Acid Based Adhesive for Composite Woods and Veneers
Chinese chemists whose recent study revisited natural glucose and citric acid as the base for a bio-based, stronger, and more water-resistant adhesive for bonding three-layer wood composites used for home furniture, floors and decor, report that they met that goal by changing two ingredients used in similar but older adhesives developed during previous studies, and at the same time found a way to meet another goal of reducing the possibility of emissions during wood bonding processes, and lowering the need for energy-intensive curing processes. According to the chemists, the change they made in the ingredients was to base their new adhesive on pure glucose (sugar) and a single ingredient found in orange juice with the citric acid instead of using sucrose, a sugar made up of both glucose and fructose, with the citric acid in previous studies.
Solutions of glucose and varying amounts of citric acid were heated into a sticky liquid which was then applied to poplar veneers. Three veneers were then pressed into a single sheet at 392° F (200° C) for six minutes, before being cut into smaller pieces for a strength test. Results indicated that under pressures greater than 101 psi, while the plywood samples did break along the wood fibers, the seams made by the glucose and citric acid adhesive remained undamaged.
According to the study team, the test not only showed that the changed ingredients in the natural adhesive provided a strong bond, but also unlike the earlier sucrose adhesive, it did not require a zinc chloride catalyst to decrease the energy consumption during curing which also lowered the strength of the bond.
Source: SciTech Daily