Carbon fiber bundle containing sizing agent and method for producing same
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Solution Overview
Problem
Carbon fibers with sizing agents face issues of thermal degradation, leading to loss of oxygen-containing functional groups and increased voids in composites, which affects their mechanical properties and handling during processing.
Innovation Solution
A carbon fiber bundle with a sizing agent composition that includes a high percentage of polyalkylene glycol structure and an acetylene structure, ensuring controlled thermal weight loss ratios to maintain surface functional groups and facilitate easy handling, even at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a sizing agent is applied to carbon fiber bundle to provide abrasion-resistant coating for easy handling, then handling ease is improved, but the sizing agent undergoes thermal degradation at high temperatures during prepreg formation
Solution Approach 1:
The patent modifies the chemical composition parameters of the sizing agent by incorporating polyalkylene glycol structures with specific molecular weights (200-600) and controlling the content of hydroxyl groups. This parameter optimization enables the sizing agent to maintain thermal stability up to 250°C while preserving its handling benefits, resolving the contradiction between ease of operation and thermal reliability.
2Manufacturing precision
If high temperature heat treatment is applied to remove sizing agent, then void volume is reduced, but oxygen-containing functional groups on carbon fiber surface are degraded
Solution Approach 1:
The patent introduces a thermally stable sizing agent composition containing polyalkylene glycol as an intermediary substance that can be selectively removed at controlled temperatures. This intermediary enables the removal process to occur at lower temperatures (250°C or below) compared to conventional sizing agents, thereby protecting the oxygen-containing functional groups on carbon fiber surfaces while still achieving void reduction through controlled degradation and removal.
3Object-generated harmful factors
If conventional sizing agent is used to prevent fuzzing, then fuzz accumulation is reduced, but gas generation increases leading to higher void volume
Solution Approach 1:
The patent changes the chemical structure parameters of the sizing agent by using polyalkylene glycol with specific molecular weight ranges (200-600) and controlling hydroxyl group content (0.5-2.0 mmol/g). These parameter modifications result in a sizing agent that produces significantly less gas during thermal degradation, thereby reducing void volume in the final composite while maintaining effective fuzz prevention capabilities.
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 solution allows for the production of carbon fiber-reinforced composites with reduced residual voids and preserved surface properties, enhancing mechanical properties and handling efficiency.
Implementation Method 1
If a sizing agent applied to carbon fibers is susceptible to thermal degradation, the sizing agent will decompose or volatilize when heated to high temperatures
Implementation Method 2
carbon fibers are oxidized by gas-phase oxidation, liquid-phase oxidation, or the like to introduce oxygen-containing functional groups, such as carboxyl and aldehyde groups, to the surface of the carbon fibers
Data Source
AI summary
A carbon fiber bundle containing a sizing agent particularly suitable for combination with a thermoplastic resin is provided, wherein the sizing agent has an appropriate level of bundling property for ease of handling and is susceptible to thermal degradation at temperatures low enough to maintain the surface properties of the carbon fibers, and wherein the residual amount of sizing agent can be reduced after the carbon fiber bundle is processed into an intermediate substrate, resulting in a reflection of the surface properties of the carbon fibers.