The go-to supplies for constructing residence furnishings, décor and flooring are composite wooden merchandise that are available giant sheets. However the glues and resins holding collectively particleboard, fiberboard and plywood often comprise formaldehyde and will launch this possible carcinogen into the air. To develop a unhazardous adhesive, researchers reporting in ACS Utilized Supplies & Interfaces have mixed glucose and citric acid — sugar and an orange juice ingredient — into a powerful, water resistant wooden glue for plywood.
To make plywood, producers glue collectively skinny layers of wooden after which treatment the fabric underneath stress and warmth, creating giant, versatile panels. Some of the widespread adhesives is a urea-formaldehyde resin as a result of it is cheap and bonds strongly to wooden. Nevertheless, formaldehyde emissions from plywood with any such resin have raised well being and environmental issues. Earlier research have proven that options of sucrose, a two-unit sugar fabricated from glucose and fructose, and citric acid type a pure and water resistant wooden glue. However a zinc chloride catalyst is required to lower the vitality consumption for the plywood curing, which additionally reduces the adhesive’s power. So, Hong Lei and colleagues needed to see if pure glucose and citric acid might produce a powerful adhesive with a much less energy-intensive curing course of.
The researchers heated options of glucose and ranging quantities of citric acid right into a sticky liquid that they utilized onto poplar veneers. Then they stacked three veneers and pressed them right into a single sheet at 392 F for six minutes. The crew lower the sheets into smaller items for power exams and located that underneath pressures better than 101 psi, the plywood samples all broke alongside the wooden fibers and never on the glued seams. These outcomes fulfill the usual requirement for plywood in China. When the plywood samples had been soaked in sizzling or boiling water, solely those made with citric acid to glucose ratios above 0.6 had adhesive strengths that happy the usual requirement. The researchers attribute these outcomes to the rise in ester hyperlinks between citric acid and wooden, which elevated the wood-binding power and water-resistance. Citric acid-glucose adhesives maintain promise for the wooden merchandise business, the researchers say.
The authors acknowledge funding from the Nationwide Pure Science Basis of China, the Yunnan Provincial Pure Science Basis, the 111 undertaking and the French Nationwide Analysis Company (ANR).