Although several protective coatings have been used on bamboo, basic properties such as transparency and durability have too often been neglected so far. As an abundant natural resource, bamboo with enhanced flame retardancy and mildew resistance after surface treatment has a wider range of applications.

Researchers have now prepared a new organic-inorganic coating by thermal curing between vanillin-derived epoxy (VEP) and hyper-branched siloxane (HPSi). When the mass ratio of VEP and HPSi was 20:28, the obtained Schiff base hybrid coating exhibited visible light transmittance of over 90% and the highest pencil hardness of 9H.

The fabricated coating also showed remarkable solvent wipe resistance (Xylene and ethanol: 1,000 cycles) and continuous abrasion (cheesecloth test: 5,000 cycles). In addition, the hydrophobic and dense coating endowed the coated bamboo with excellent mildew resistance even in high humidity (97%).

Due to the high thermal stability, the coated bamboo presented a significantly enhanced flame resistance with a limiting oxygen index value of 29.1%. From a broader perspective, the Schiff base hybrid coating with excellent comprehensive performance and facile preparation process displays great potential for practical application for bamboo or other substrates.

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