Extruded PAN Copolymer Fiber With Halogen-Free Flame Retardancy
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Solution Overview
Problem
Polyacrylonitrile (PAN) fibers have poor flame retardant properties and existing solutions, such as hydrazine hydrate treatment, are hazardous and environmentally toxic, while halogenated polymers pose health and environmental hazards, necessitating a safer and more effective method for enhancing flame resistance.
Innovation Solution
A process involving a copolymer of polyacrylonitrile with a halogen-free comonomer, incorporating metal ions like zinc or silicon, which are added during the extrusion of the copolymer melt to create a fiber with reduced crystallinity and enhanced flame retardancy, measured by a limiting oxygen index (LOI) of at least 40, without the use of toxic chemicals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halogenated polymers or flame retardant chemicals are used to improve flame resistance, then flame retardant properties are enhanced, but toxic off-gases are produced and environmental hazards increase
Solution Approach 1:
The invention changes the chemical composition parameters by using halogen-free comonomers (such as acrylic acid, methacrylic acid, or their esters) instead of traditional halogenated flame retardants. This substitution maintains flame resistance through alternative chemical mechanisms while eliminating toxic halogenated off-gases during combustion
Solution Approach 2:
The invention creates a composite polymer system by copolymerizing acrylonitrile with halogen-free comonomers. This composite structure integrates the flame-resistant properties of acrylonitrile with the safety benefits of halogen-free components, achieving both fire safety and environmental compatibility in a single material system
2Reliability
If hydrazine hydrate is used to treat PAN to improve flame resistance, then flame retardant properties are enhanced, but handling safety and environmental toxicity worsen
Solution Approach 1:
The invention incorporates flame-resistant halogen-free comonomers into the polymer chain during the initial polymerization process, eliminating the need for subsequent hazardous post-treatment with hydrazine hydrate. The flame resistance is built-in from the start, avoiding all handling risks associated with toxic chemicals
Solution Approach 2:
The invention completely removes hydrazine hydrate and other hazardous post-treatment chemicals from the manufacturing process. By achieving flame resistance through copolymerization alone, the process extracts and eliminates all steps involving toxic substances, improving worker safety and environmental performance
3Manufacturing precision
If wet-spinning process is used to produce PAN fibers, then fiber quality is achieved, but process complexity and cost increase
Solution Approach 1:
The invention changes the processing parameters by enabling melt extrusion through careful selection of halogen-free comonomers and control of molecular weight. This parameter change transforms the process from complex wet-spinning requiring solvent handling to simpler melt extrusion, reducing equipment complexity and operational costs while maintaining fiber quality
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 resulting fibers are non-combustible, exhibit reduced fume emission when exposed to flames, and possess antimicrobial properties, making them suitable for flame-resistant and antimicrobial applications without the hazards associated with traditional treatments.
Implementation Method 1
incorporating metal ions like zinc or silicon, which are added during the extrusion of the copolymer melt to create a fiber with reduced crystallinity and enhanced flame retardancy
Implementation Method 2
create a fiber with reduced crystallinity and enhanced flame retardancy
Implementation Method 3
A process involving a copolymer of polyacrylonitrile with a halogen-free comonomer, incorporating metal ions like zinc or silicon, which are added during the extrusion of the copolymer melt to create a fiber
Implementation Method 4
The resulting fibers are non-combustible, exhibit reduced fume emission when exposed to flames
Data Source
Figure 1~2
AI summary
The invention relates to a polymeric fibre derived from a copolymer of polyacrylonitrile and a comonomer. The fibre comprises a metal ion and/or silicon at from about 1 to about 15 wt%. A process for making the fibre is also described.