Multifunctional Flame-Retardant, Thermal Insulation, and Antimicrobial Wood-Based Composites

Abstract

Wood has been used in a variety of applications in our daily lives and military industry. Nevertheless, its flammability causes potential fire risks and hazards. Improving the flame retardancy of wood is a challenging task. Herein, a phytic acid-based flame retardant (referred to as AMPA) was synthesized based on supramolecular reactions between melamine and p-amino-benzene sulfonic acid followed by a reaction with phytic acid using deionized water as the solvent. A composite wood was prepared by removing lignin to tailor the unique mesoporous structure of the material, followed by coating AMPA on the surfaces of wood microchannels. The limiting oxygen index of wood has been improved to 52.5% with the addition of 5.6 wt % AMPA. The peak heat release rate for the prepared composite wood was reduced by 81% compared to that for delignified wood, which demonstrates the excellent flame-retardant performance of the prepared composite wood. Furthermore, AMPA and mesoporous structures endow antimicrobial and thermal insulation functions. Hence, this work provides a feasible method for preparing flame-retardant wood-based materials for diversified applications.

Fire‐retardant and high‐strength polymeric materials enabled by supramolecular aggregates

“…[88][89][90][91] Recently, PA has been widely utilized to react with amines and MEL to prepare P-N fire retardants based on ionic interactions. [92][93][94] For example, Zhang et al [95] synthesized a phytic acid-based fire-retardant coating (AMPA) based on ionic interactions between pamino-benzene sulfonic acid and MEL followed by a reaction with PA (Figure 12A). After coating 5.6 wt% AMPA on the surfaces via H-bonding, the thermal stability of sample woods is improved, with high char yields (40 wt%) at 800 • C (Figure 12B).…”

Synthesis and Applications of Supramolecular Flame Retardants: A Review

“…This is because during the self-assembly process, Mn 2+ was added to the MEL-PA supramolecular structure, which affected the strength of internal interaction forces and made the assembly skeleton expand outward. In addition, based on MEL and PA raw materials, other organic or inorganic compounds were selected for multi-component self-assembly, demonstrating the flexibility of supramolecular self-assembly ( Figure 5 c) [ 58 , 59 , 60 , 61 ]. Introduced components, such as sulfanilic acid [ 60 ] and amine-functionalized AL 2 O 3 [ 61 ], have multiple active sites and are capable of self-assembly with MEL-PA in the aqueous phase through multiple synergies such as ion attraction and hydrogen bonding.…”

Nb2CTx MXene/Delignified Wood–Supported Phase-Change Composites with Desirable Photothermal Conversion Efficiency and Enhanced Flame Retardancy for Solar–Thermal Energy Storage

“…MXenes are novel two-dimensional (2D) materials with the representative formula M n +1 X n T x (where M represents transition metals Ti, Nb, or Mo, X represents carbon or/and nitrogen, and T x denotes surface terminal −OH and −F) and have recently attracted intensive attention for solar–thermal conversion. − Notably, among photothermal conversion materials, monolayer Nb 2 C MXene is considered the most promising owing to its satisfactory characteristics, including nearly 100% solar–thermal conversion efficiency, thermal and electrical conductivity, and a wide range of absorption spectra. − Phytic acid (PA), an organophosphorus compound derived primarily from the roots of cereal legumes, has been exploited as an effective flame retardant in numerous polymers owing to its biocompatibility and high phosphorus content of up to 28 wt % . Synergistic phosphorus–nitrogen retardants have recently shown broad application prospects for wood flame retardance owing to their high flame retardancy, halogen-free characteristic, and low toxicity. , Incorporating melamine (MEL) as a nitrogen source with PA as a phosphorus source can generate a synergistic phosphorus–nitrogen retardant effect during combustion. − Therefore, impregnating n -docosane into PA/MEL-modified Nb 2 CT x MXene/DW enables the fabrication of form-stable PCM composites with excellent flame retardancy and desirable photothermal conversion efficiency. Moreover, PCM composites with good thermal storage and photothermal conversion capabilities are expected to be leveraged in the construction field.…”