Phosphite-Modified Cellulose Film for Flame Retardancy
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Solution Overview
Problem
Untreated microcrystalline cellulose has a high flammability, limiting its application in flame retardant requirements, and existing modification methods do not effectively enhance its flame retardancy.
Innovation Solution
A method involving the use of an ionic liquid cosolvent system to dissolve cellulose, followed by transesterification with dimethyl phosphite and a catalyst to introduce phosphite ester groups, and subsequent solvent evaporation to form a flame retardant cellulose ester film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If untreated microcrystalline cellulose is used, then the material is renewable and biodegradable, but the flame retardancy is poor with residual carbon rate only 0.37%
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of cellulose through phosphorylation, introducing phosphorus-containing groups that fundamentally alter the thermal decomposition behavior. This chemical modification transforms the residual carbon rate from 0.37% to 30.4-33.7%, resolving the contradiction between maintaining cellulose's renewable properties and achieving flame retardancy.
Solution Approach 2:
The patent creates a composite material system by combining cellulose with phosphorus-containing compounds through esterification reactions. The resulting cellulose phosphate ester integrates the renewable characteristics of cellulose with the flame retardant properties of phosphorus compounds, achieving both environmental friendliness and fire safety.
2Object-affected harmful factors
If conventional modification methods are used, then some functionalization is achieved, but flame retardancy is not effectively enhanced
Solution Approach 1:
The patent achieves effective flame retardancy by changing the chemical parameters through phosphorylation modification, introducing P-O-C bonds that fundamentally alter the material's thermal stability and fire resistance properties, overcoming the limitations of conventional modification approaches.
Solution Approach 2:
The patent uses an ionic liquid cosolvent system as an intermediary to facilitate the phosphorylation reaction. This intermediate medium enables efficient interaction between cellulose and phosphorus compounds, ensuring thorough modification and effective flame retardancy enhancement that conventional methods cannot achieve.
3Object-affected harmful factors
If cellulose is modified to improve flame retardancy, then functionalization is achieved, but the processing complexity increases
Solution Approach 1:
The patent employs an ionic liquid cosolvent system as a mediator that simplifies the modification process. This intermediate medium facilitates homogeneous reaction conditions, improves reagent penetration, and enables efficient phosphorylation, thereby reducing processing complexity while achieving effective flame retardancy.
Solution Approach 2:
The patent optimizes reaction parameters including temperature, time, and reagent ratios to achieve efficient modification. By carefully controlling these parameters, the patent reduces processing complexity while ensuring thorough phosphorylation and effective flame retardancy enhancement.
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 method significantly improves the flame retardancy of cellulose, achieving a residual carbon rate of 30.4-33.7% and producing a film that does not release toxic gases during thermal decomposition, suitable for applications like coatings and packaging films.
Implementation Method 1
obtaining a homogeneous cellulose solution by adding cellulose to an ionic liquid cosolvent system
Implementation Method 2
obtaining a cellulose phosphite ester solution by adding dimethyl phosphite and a catalyst to the homogeneous cellulose solution obtained in step (a) for performing a transesterification
Implementation Method 3
obtaining a cellulose phosphite ester solution by adding dimethyl phosphite and a catalyst to the homogeneous cellulose solution obtained in step (a) for performing a transesterification
Implementation Method 4
obtaining cellulose phosphite ester powder by regeneration solvent precipitation, washing, centrifugation, and drying of the cellulose phosphite ester solution obtained in step (b)
Implementation Method 5
obtaining the flame retardant cellulose ester film by evaporating solvent after dissolving the cellulose phosphite ester powder obtained in step (c) in dimethyl sulfoxide
Data Source
AI summary
Provided is a modified cellulose, a preparation method and application thereof. The modified cellulose includes a flame retardant cellulose ester film, and the preparation method includes: obtaining a homogeneous cellulose solution by adding a cellulose to an ionic liquid cosolvent system; obtaining a cellulose phosphite ester solution by adding dimethyl phosphite and a catalyst to the homogeneous cellulose solution for performing a transesterification; obtaining cellulose phosphite ester powder by regeneration solvent precipitation, washing, centrifugation, and drying of the cellulose phosphite ester solution; and obtaining the flame retardant cellulose ester film by evaporating solvent after dissolving the cellulose phosphite ester powder in dimethyl sulfoxide.