Preparation of Hydrophilic and Fire-Resistant Phytic Acid/Chitosan/Polydopamine-Coated Expanded Polystyrene Particles by Using Coating Method

Abstract

Expanded polystyrene (EPS) particles are commonly used for thermal insulation in lightweight building materials due to their low density, low thermal conductivity, and affordability. However, shortcomings such as hydrophobicity and poor fire safety limit the application of EPS. Bio-based flame retardants have been developed for use in polymer composites due to their renewable, environmentally friendly, and non-toxic properties. In this study, to improve the hydrophilicity and fire resistance of EPS particles, phytic acid (PA)/chitosan (CS)–polydopamine (PDA)@EPS particles (PA/CS-PDA@EPS) with a bio-based coating were prepared by using a simple coating method based on PDA@EPS particles using PDA as an adhesive and PA and CS as bio-based flame retardants. The results showed that the modified EPS particles had good hydrophilicity, the residual carbon yield of the 10PA/3CS-PDA@EPS samples was increased to 24 wt%, and the maximum loss rate was reduced by 69% compared with unmodified EPS. In flammability tests, the 10PA/3CS-PDA@EPS samples also demonstrated low flame spread and some fire resistance. Furthermore, the modified EPS particles exhibited fire resistance even after multiple washings. The hydrophilic and fire-resistant modified EPS particles are anticipated to offer a novel approach to the advancement of EPS-based lightweight building materials.