Study of the structural properties and degradation of coated wood with polydopamine/hydroxyapatite/chitosan hybrid nanocomposite in seawater

Abstract

Increasing environmental concerns and increasing demands for reproducible natural resources have made wood a viable option for use in various industries, particularly the marine industry. In this study, the wood was treated with three coatings, and then its biodegradability in the marine environment was investigated. The first coating, inspired secreted substance from bivalve mollusks called dopamine was used, which has the ability to adhere to different surfaces. The second coating, hydroxyapatite crystals were formed by immersion of treated wood for 14 days in simulated body fluid (SBF) × 1.5 solutions. Extracted chitosan from shrimp waste was used for the third layer. The contact angle (CA) of the treated wood with polydopamine/hydroxyapatite/chitosan showed 130°. The results of FT-IR, XRD, and FE-SEM confirmed the layers on the surface of the wood. In the next step, control and treated woods were exposed to seawater for 6 months. The results showed that the control woods had more color variations than the treated woods with more swelling, more infestation of barnacles. The results of FT-IR and XRD showed that structures of lignin, cellulose, and hemicelluloses of the control wood were more demolished than those of treated wood after immersion in seawater.