PAN Precursor Spinning with High-Purity DMSO Polymerization Control
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Solution Overview
Problem
The quality of polyacrylonitrile-based precursor fibers significantly affects the properties of carbon fibers, particularly mechanical strength, and existing manufacturing methods do not effectively ensure high purity, molecular weight, spinnability, crystallinity, and polymerization conversion degree, leading to inconsistent carbon fiber performance.
Innovation Solution
A manufacturing method involving the use of a first solvent with a high dimethyl sulfoxide content, controlled impurity levels, and specific polymerization conditions to produce a copolymerized polymer with targeted molecular weight, dispersibility index, and viscosity, followed by controlled spinning and condensing processes to form nascent carbon fibers, which are then processed through washing, oiling, drying, and calcination to achieve high mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional solvents with lower purity are used in polymerization, then manufacturing cost is reduced, but the polymerization conversion degree and molecular weight of the copolymerized polymer deteriorate
Solution Approach 1:
The patent applies parameter changes by strictly controlling the purity of dimethyl sulfoxide solvent to 99.9% or higher, and controlling impurity levels (methylsulfonylmethane ≤0.0004 wt%, dimethyl sulfide ≤0.0008 wt%). This parameter control ensures high polymerization conversion degree (90-100%) and optimal molecular weight (300,000-500,000 g/mole) of the copolymerized polymer, resolving the contradiction between manufacturing precision and ease of manufacture.
2Strength
If polyacrylonitrile-based precursor fibers with inconsistent quality are used, then manufacturing process is simplified, but the mechanical strength and physical properties of carbon fibers deteriorate
Solution Approach 1:
The patent controls multiple parameters including solvent purity (99.9% DMSO), impurity levels, polymerization conversion degree (90-100%), molecular weight (300,000-500,000 g/mole), and dispersibility index (1.5-3.0). These parameter controls ensure consistent quality of polyacrylonitrile-based precursor fibers, which directly improves the mechanical strength of carbon fibers while maintaining manageable process complexity through systematic control.
Solution Approach 2:
The patent implements feedback control by monitoring and controlling the dispersibility index (1.5-3.0) and molecular weight distribution of the copolymerized polymer during manufacturing. This feedback mechanism ensures that precursor fibers meet specified quality standards, which then translates to consistent mechanical strength in the final carbon fiber product.
3Ease of operation
If copolymerized polymer with inadequate molecular weight control is produced, then polymerization process is simplified, but the spinnability and structural stability of the fiber deteriorate
Solution Approach 1:
The patent applies parameter changes by controlling the molecular weight of copolymerized polymer to be between 300,000-500,000 g/mole and dispersibility index to be between 1.5-3.0. These parameter specifications optimize the spinnability of the polymer while ensuring structural stability of the resulting fiber, resolving the contradiction between ease of operation and device complexity.
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 results in carbon fibers with improved mechanical strength, spinnability, and structural stability, enabling wider application in industries requiring high-performance carbon fibers.
Implementation Method 1
a polymerization reaction is performed to form a copolymerized polymer
Implementation Method 2
A condensing step is performed on the filamentous copolymerized polymer by using a condensing bath to form a nascent carbon fiber
Data Source
AI summary
A manufacturing method for a carbon fiber includes the following steps. A first monomer and a second monomer are dissolved in a first solvent, and a polymerization reaction is performed to form a copolymerized polymer, in which the first monomer includes acrylonitrile, the second monomer has an unsaturated bond, the first solvent includes dimethyl sulfoxide, and based on 100 wt % of the first solvent, a content of the dimethyl sulfoxide is between 99.9 wt % and 100 wt %. A spinning step is performed on the copolymerized polymer.