Mechanochemical Chitosan–Phytic Acid Complex for Epoxy Fire Protection

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Solution Overview

Problem

There is a lack of effective, non-toxic, and environmentally friendly flame retardants based on renewable resources for polymeric composites, particularly in sectors with high fire resistance requirements, and existing synthesis methods are energy-intensive and solvent-dependent.

Innovation Solution

A polyelectrolyte complex composed of chitosan and phytic acid, synthesized through mechanochemical methods, which involves mechanical energy to form a powdery solid with high phosphorus content, offering fireproof, antimicrobial, and antioxidant properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If halogenated flame retardants are used to achieve effective fire resistance, then flame retardancy is improved, but smoke toxicity and environmental harm increase

Engineering Contradiction:
Improvefire resistanceVSAvoidsmoke toxicity
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention changes the chemical composition parameters by using phosphorus-based compounds (ammonium polyphosphate, phosphoric acid) instead of halogenated compounds, maintaining flame retardancy while eliminating smoke toxicity. The polyelectrolyte complex achieves effective fire resistance through phosphorus-containing intumescent mechanisms that do not produce harmful smoke.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite polyelectrolyte complex structure combining chitosan with phosphorus-containing compounds. This composite material integrates the flame retardant properties of phosphorus compounds with the biodegradable, non-toxic characteristics of chitosan, achieving both fire resistance and environmental safety.

Inventive Principle:
Principle #40Composite materials

2Quantity of substance

If conventional synthesis methods are used to produce polyelectrolyte complexes, then product formation is achieved, but solvent consumption and energy use increase

Engineering Contradiction:
Improvepolyelectrolyte complex productionVSAvoidsolvent consumption
Core Design Contradiction:
Quantity of substanceVSLoss of substance

Solution Approach 1:

The invention extracts and eliminates the solvent component from the synthesis process by using mechanochemical methods. The polyelectrolyte complex is formed through solid-state reactions or reactions in minimal water, removing the need for large volumes of organic solvents that would require energy-intensive evaporation and disposal.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces thermal/chemical synthesis methods with mechanochemical synthesis. Mechanical energy (ball milling, extrusion) is used to activate the reaction between chitosan and phosphorus compounds, substituting the need for solvents and reducing energy consumption associated with heating and solvent recovery.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If traditional flame retardant additives are used in polymeric composites, then fire resistance is improved, but environmental sustainability deteriorates

Engineering Contradiction:
Improvefire resistanceVSAvoidenvironmental impact
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the material origin parameter from fossil-based to bio-based. Chitosan is derived from renewable crustacean shell waste, and the phosphorus compounds can be sourced from natural minerals or biological processes. This parameter change makes the flame retardant system environmentally sustainable while maintaining fire resistance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses biodegradable chitosan as the base material for the polyelectrolyte complex. Chitosan naturally degrades in the environment through microbial action, eliminating persistent environmental pollution. The flame retardant system is designed to be environmentally benign and non-persistent.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Object-generated harmful factors

If phosphorus-based flame retardants are used as halogen-free alternatives, then smoke toxicity is reduced, but flame retardant effectiveness may be compromised

Engineering Contradiction:
Improvesmoke toxicityVSAvoidflame retardancy
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The invention creates a composite polyelectrolyte complex where chitosan and phosphorus compounds work synergistically. The complex structure enhances the flame retardant effectiveness of phosphorus-based additives through intumescent mechanisms, maintaining or improving fire resistance compared to conventional phosphorus additives while preserving low smoke toxicity.

Inventive Principle:
Principle #40Composite materials

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 polyelectrolyte complex provides enhanced fire resistance, reduces environmental impact, and minimizes energy consumption and solvent use, while exhibiting synergistic effects with conventional flame retardants.

Implementation Method 1

wherein chitosan and phytic acid are bound by means of electrostatic forces

Methodology Applied
Scientific EffectElectrostatic forces: Electrostatics

Data Source

PatentEP4632040A1Polyelectrolyte complex made of chitosan and phytic acid, production method and use thereof
Publication Date: 2025.10.15 ASOCIACION DE INVESTIGACION DE MATERIALES PLASTICOS & CONEXAS
  • EP4632040A1 patent drawingFigure 1~2
  • EP4632040A1 patent drawingFigure 3~4
  • EP4632040A1 patent drawingFigure 5

AI summary

The present invention relates to a polyelectrolyte complex consisting of chitosan and phytic acid, the method for producing said polyelectrolyte complex using mechanochemical synthesis and its use as an antimicrobial and antioxidant bio-fire-retardant additive for epoxy resins. Furthermore, the present invention relates to a material comprising said polyelectrolyte complex and a polymer, preferably an epoxy resin, an article coated with said flame retardant and an article having said flame retardant embedded therein. Therefore, the present invention is framed within the fireproof plastics industry with high anti-fire demands such as the automotive industry, aeronautics, construction or the electrical-electronic sector.