Enhancing wood composite materials with formaldehyde-removing microcapsules featuring long-lasting, slow-release, and environmentally benign characteristics.

The long-term emission of free formaldehyde from plywood is a common problem, and the addition of formaldehyde capture agents typically reduces the plywood bonding performance. In this paper, melamine(ME)@sodium alginate (SA)/ethyl cellulose (EC) double-shell microcapsules (MEM) were prepared for the first time by the sol-gel method. The preparation process was optimized by response surface methodology via Box-Behnken design, and the results were highly reliable. MEM showed good spheroidizing properties, and its coating rate reached 71.97%. When 8% MEM was added to plywood, the emission of formaldehyde decreased by 47.67%. Moreover, the bonding strength reached 1.27 MPa, which was 8.32% higher than that of the control group. This performance met both the mainstream E0-grade formaldehyde emission standard as well as the national Class II plywood standard of China, solving the problem of formaldehyde pollution in the environment. Therefore, MEM addresses the trade-off between mitigating the harm to human health and avoiding a reduction in plywood performance when using formaldehyde scavengers. Compared with tea polyphenol@SA/EC(TPM) and sodium chlorite@SA/EC(CDM) with different core materials, MEM is a promising low-cost microcapsule agent. This research provides potential alternatives for improving indoor air quality, green building certification, and replacing traditional inefficient cleaning methods.