Cellulosic Flame-Retardant Treatment for Wash-Durable Fire Resistance
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Solution Overview
Problem
Current methods for enhancing the fire resistance of cellulosic materials in polymer composites are limited by the use of harmful halogen-based flame retardants and inefficient alternatives like boron and phosphorous compounds, which either harm the environment or require high concentrations, failing to adequately address flammability issues, especially when cellulose content is significant.
Innovation Solution
Treating cellulosic materials with an aqueous mixture of alkali metal or ammonium hydroxide and alkaline-earth or aluminum metal salts simultaneously, followed by drying, to create a self-extinguishing material with improved thermal stability and interfacial thermal resistance, and optionally further treating with layered nanoparticulate materials for enhanced fire resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halogen-based flame retardants are used to improve fire resistance of cellulosic materials, then fire resistance is enhanced, but environmental harm increases
Solution Approach 1:
The invention changes the chemical composition parameters by replacing halogen-based flame retardants with an aqueous mixture containing alkali metal hydroxide (such as sodium hydroxide or potassium hydroxide) and alkaline-earth metal salts (such as barium chloride, barium nitrate, or barium sulfate). This parameter substitution maintains fire resistance while eliminating the environmental harm associated with halogen compounds.
2Reliability
If boron compounds are used as flame retardants, then fire resistance is improved, but the flame retardant is washed off due to water solubility
Solution Approach 1:
The invention introduces alkali metal hydroxide as an intermediary substance that reacts with water-soluble flame retardants to form insoluble metal hydroxide precipitates. This intermediary reaction converts the soluble boron compounds into insoluble forms that remain firmly attached to the cellulosic material, preventing wash-off while maintaining fire resistance.
3Object-affected harmful factors
If phosphorous, graphite or alkaline-earth metallic compounds are used as flame retardants, then environmental harm is reduced, but fire resistance efficiency decreases requiring large amounts of additives
Solution Approach 1:
The invention creates a composite flame retardant system by combining alkali metal hydroxide with alkaline-earth metal salts in an aqueous mixture. This composite approach leverages the complementary properties of both components: the alkali metal hydroxide provides immediate fire protection and the alkaline-earth metal salts contribute to long-term stability. The synergistic interaction between these components achieves high fire resistance efficiency with reduced additive quantities compared to using either component alone.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process results in fire-resistant cellulosic materials with improved mechanical properties and reduced environmental impact, maintaining effectiveness even after washing, and enhances the fire resistance of polymer composites without significant negative effects on mechanical performance.
Implementation Method 1
treating a cellulosic material with an aqueous reaction mixture of an alkali metal or ammonium hydroxide and an alkaline earth or aluminum metal salt
Implementation Method 2
drying the treated cellulosic material
Data Source
AI summary
A new approach for improving fire resistance of cellulosic materials is provided, especially when the cellulosic material is to be used in polymer composites. Cellulosic material is treated with an aqueous mixture of alkali metal or ammonium hydroxide and alkaline earth or aluminum metal salt simultaneously with or within a short period of time of preparing the mixture. The treated cellulosic material becomes self-extinguishing and may also have improved thermal stability, improved interfacial thermal resistance, improved resistance to damage by oxidants and other chemical agents, improved resistance to biological agents and/or improved resistance to damage by ultra-violet light.