Epoxy Resin Composition for Composite Materials
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Solution Overview
Problem
Current epoxy resin compositions used in fiber-reinforced composite materials face challenges in maintaining high mechanical strength at low temperatures and are prone to void formation due to volatile content, which affects adhesion and strength, especially when cured at high temperatures.
Innovation Solution
An epoxy resin composition comprising a bifunctional or monofunctional epoxy resin with specific glycidyl groups and a tri-functional epoxy resin, combined with a curing agent, which reduces volatile content and enhances heat resistance and mechanical strength, suitable for producing carbon fiber reinforced composite materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a high glass transition temperature resin composition is used to achieve high heat resistance, then heat resistance is improved, but volatile matter content increases causing void formation and decreased strength
Solution Approach 1:
The invention changes the chemical composition parameters of the epoxy resin system by combining specific types of epoxy resins (cyclic, aliphatic, aromatic) in controlled ratios with curing agents, thereby achieving high Tg without excessive volatile matter content. This parameter optimization resolves the contradiction between heat resistance and strength.
Solution Approach 2:
The invention creates a composite epoxy resin system by combining multiple epoxy resin types (cyclic, aliphatic, aromatic) with curing agents in specific proportions. This composite approach allows the system to achieve both high heat resistance and low volatile matter content, thereby maintaining strength while improving thermal properties.
2Strength
If high strength reinforcement fiber is used to increase fiber strength, then fiber strand strength is improved, but the rate of contribution to tensile strength decreases
Solution Approach 1:
The epoxy resin composition acts as an intermediary between the reinforcement fiber and the external load. By optimizing the resin's mechanical properties and interfacial adhesion characteristics, the system enables high-strength fibers to contribute more effectively to the composite's tensile strength, resolving the contradiction between fiber strength and tensile strength contribution.
3Reliability
If curing is performed at high temperature of 180°C or more to achieve complete curing, then curing completeness is improved, but thermal stress increases preventing high strength development
Solution Approach 1:
The invention changes the curing parameters by selecting curing agents and resin compositions that enable effective curing at lower temperatures (below 180°C). This parameter adjustment reduces thermal stress while maintaining curing completeness, thereby resolving the contradiction between curing completeness and thermal stress.
4Reliability
If high fiber volume fraction is used to increase strength, then fiber content is improved, but processability deteriorates
Solution Approach 1:
The invention optimizes the viscosity and flow characteristics of the epoxy resin composition through selective component combination and ratio control. This parameter optimization allows the resin to adequately impregnate high fiber volume fractions while maintaining processability, thereby resolving the contradiction between strength and ease of manufacture.
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 proposed epoxy resin composition results in fiber-reinforced composite materials with high heat resistance and mechanical strength at low temperatures, reducing void formation and improving adhesion, making them suitable for structural applications such as aircraft components and sports equipment.
Implementation Method 1
the curing of a prepreg, i.e. a sheet-like intermediate material produced by impregnating reinforcement fiber with uncured matrix resin
Implementation Method 2
these resin compositions commonly contain much volatile constituents that volatilize when exposed to a high temperature during curing or molding processes
Data Source
AI summary
Disclosed is a fiber-reinforced composite material that is high in heat resistance and strength while being low in the content of volatile matter that volatilizes during curing. Also disclosed are an epoxy resin composition for production thereof, and a prepreg produced from the epoxy resin composition. Specifically the invention provides an epoxy resin composition comprising: [A] an epoxy resin comprising two or more ring structures each consisting of four or more members, and at least one amine type or ether type glycidyl group directly connected to the ring structures, [B] a tri-or more-functional epoxy resin, and [C] a curing agent, and also provides a prepreg produced by impregnating reinforcing fiber with the epoxy resin composition and a fiber-reinforced composite material produced by curing the prepreg.