Phosphorylated Lignin Flame Retardant via Phytic Acid Modification
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Solution Overview
Problem
Current flame retardant materials, such as halogenated and mineral-based compounds, pose environmental and health risks due to their persistence, bioaccumulation, and potential carcinogenicity. Additionally, they often require high quantities to achieve desired fire resistance characteristics.
Innovation Solution
The development of a method to modify lignin with phytic acid, a bio-based reagent containing six phosphorous molecules, to create a phosphorylated lignin composition with improved flame retardancy. This involves mixing lignin with phytic acid in water at specific ratios and pH levels, followed by recovery of the modified lignin composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halogenated flame retardants are used, then flame retardancy efficiency is improved, but environmental and health safety deteriorates due to persistence, bioaccumulation, and carcinogenicity
Solution Approach 1:
The patent changes the chemical composition parameters by replacing halogenated compounds with phosphorus-containing biobased compounds derived from lignin and phytic acid. This parameter change maintains flame retardancy through phosphorus-based mechanisms (char formation, radical quenching) while eliminating the harmful persistence, bioaccumulation, and carcinogenicity associated with halogenated flame retardants
Solution Approach 2:
The patent creates a composite flame retardant system by combining lignin (a biopolymer matrix) with phytic acid (a phosphorus-rich compound). This composite material integrates the structural benefits of lignin with the flame-retardant properties of phosphorus, achieving both effectiveness and environmental safety
2Reliability
If mineral flame retardants such as aluminum trihydroxide are used, then fire risk reduction is improved, but the quantity of material required increases significantly
Solution Approach 1:
The patent changes the efficiency parameter by using phosphorus-containing compounds that act at lower concentrations compared to mineral flame retardants. The phosphorus compounds promote char formation and release protective gases more efficiently, reducing the quantity needed to achieve the same fire resistance level
Solution Approach 2:
The patent uses biobased lignin as a carrier matrix that can be applied in coating solutions, replicating the protective function of mineral flame retardants but with higher efficiency per unit mass, thereby reducing the overall quantity required
3Reliability
If phytic acid is used as an additive to biomaterials, then flame retardancy is improved, but mechanical properties and processability deteriorate due to leaching
Solution Approach 1:
The patent merges phytic acid with lignin through covalent bonding to create a unified phosphorylated lignin molecule. This combination prevents leaching by integrating the flame-retardant phytic acid into the lignin structure, thereby maintaining both flame retardancy and mechanical integrity
Solution Approach 2:
The patent performs preliminary chemical modification by phosphorylating lignin before application. This pre-bonding of phytic acid to lignin ensures that the flame retardant properties are locked into the material structure in advance, preventing subsequent leaching that would compromise mechanical properties
4Ease of manufacture
If lignin is used in pristine form, then biodegradability and availability are improved, but flame retardancy efficiency deteriorates
Solution Approach 1:
The patent creates a composite structure by integrating phosphorus-containing phytic acid into the lignin matrix. This composite maintains the biodegradability and availability of lignin while adding the flame-retardant properties of phosphorus, achieving both ease of manufacture and fire resistance
Solution Approach 2:
The patent modifies the chemical parameters of lignin by introducing phosphorus groups through phosphorylation. This parameter change enhances flame retardancy efficiency while preserving the biopolymer's inherent biodegradability and availability characteristics
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 modified lignin composition exhibits enhanced thermal stability and flame retardancy, as demonstrated by increased limiting oxygen index values and reduced smoke density ratings. The phosphorylation process improves the char forming abilities of lignin, leading to a more effective flame retardant material.
Implementation Method 1
mixing a quantity of lignin with phytic acid in water at a ratio of about 1 part lignin per about 0.2 to about 0.6 parts phytic acid (mol/mol) at a pH of about 9 to about 12 for at least about 20 minutes at a temperature of about 20-80° C.
Implementation Method 2
the phosphor containing flame retardant can function via promoting carbonization, dehydrogenation, and physical protective layer properties
Implementation Method 3
the phosphor containing flame retardant can function via promoting carbonization, dehydrogenation, and physical protective layer properties
Data Source
AI summary
Kraft lignin was modified with phytic acid (C6H18O24P6 PHA), a bio-based reagent with high amount of phosphorus, in a facile solvent-free reaction at low temperature, to produce a novel reactive bio-based flame retardant. The thermochemical properties of the fabricated lignin derivative were comprehensively analyzed by advanced tools, such as 1H NMR, 31P NMR, HSQC-NMR, XPS, ICP-AES, TGA, and DSC. A smoke detector and limiting oxygen index investigated the flame retardancy behavior of modified lignin used for coating wood samples.