Fabrication of superior flame-retardant phosphorylated chitosan biobased porous composites reinforced by superhydrophobic silicone interpenetrating crosslinking networks.

Chitosan-based porous materials have potential to develop into a new generation of high performance sustainable thermal insulation materials. In this study, hydrophobic and enhanced phosphorylated porous materials (PCSM) were constructed by the in-situ crosslinking of methytrimethoxylsilane (MTMS), and modified SiO nanoparticles (H-SiO) were further incorporated into the crosslinking networks to fabricate superhydrophobic and reinforced PCSM-H-SiO porous composites. The morphology of PCSM-H-SiO porous materials exhibited special micro-nanoscale "pearl string-like" rough and interpenetrating pore wall structure, which endowed them superhydrophobicity and self-cleaning ability. The water contact angles (WCAs) of PCSM-H-SiO porous composites achieved up to 150, and the compressive and specific moduli of PCSM2-H-SiO-2 porous composite significantly increased to 11.0 MPa and 89.6 m·s, 5.39 and 1.74 times higher than those of PCS porous material, respectively. The limited oxygen index (LOI) values of PCSM2-H-SiO-2 porous composite were above 80 %. The cone calorimeter test result demonstrated the peak heat release rate and total heat release rate values of PCSM-H-SiO-2 porous composite were lower than those of PCS porous material. The ultra-high flame-retardant PCSM-H-SiO-2 porous composite with superhydrophobicity and excellent compressive property is a promising biodegradable thermal-insulation material as replacement of petroleum-based material.