Preparation of wood-based surface coatings with dual functions of flame retardancy and superhydrophobicity by sand-in method

Abstract

The natural defects of wood limit their use. In this study, an Al₂O₃@EP@PDMS composite coating was successfully prepared on the surface of the wood substrate using the sand-in method to obtain a bifunctional coating with both superhydrophobic and flame retardant properties. It was found that the coating uniformly covers the surface of the wood substrate and provides mechanical, chemical and flame retardant properties such as abrasion and corrosion resistance. The limiting oxygen index (LOI) of superhydrophobic coated wood (SH-Wood) was increased from 19.8 % to 28.2 % for untreated wood (Natural Wood). CONE calorimetry tests showed that SH-Wood had 33.8 % less total heat release, 49.5 % less peak heat release, and a 23.2 % reduction in total smoke production, compared to Natural Wood by 23.2 %. The water repellency of the coating is greatly improved, with a water contact angle of 157° and a sliding angle of 2.3°. What's more, SH-Wood was exposed to different corrosive liquids and high temperatures of 100 °C, as well as tested by abrasion, peeling and scratching, which confirmed the excellent durability of the coating on the wood surface. The results of the study provide new ideas for the preparation of wood surface coatings with dual functions of superhydrophobicity and flame retardancy.