Prepreg Composite Interlayer Toughness via Polyamide Particles
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Solution Overview
Problem
Fiber-reinforced composite materials face challenges in achieving stable mode I and mode II interlayer fracture toughness, especially when subjected to complex shapes and varying production conditions, due to insufficient interfacial properties between reinforcement fibers and matrix resins, leading to inadequate compressive strength and toughness.
Innovation Solution
A prepreg composition including a reinforced fiber substrate, an epoxy resin composition, and polyamide or spherical polyamide particles with thermosetting polyimide particles, where the polyamide particles have a melting point of 140° C to 175° C, and the thermosetting polyimide particles are strategically distributed to enhance interlayer fracture toughness, regardless of curing temperature or temperature increase rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cured thermosetting resin composition is used as matrix resin, then cost, productivity, and heat resistance are improved, but toughness of interlayer region becomes insufficient
Solution Approach 1:
The patent combines cured thermosetting resin composition with thermoplastic resin particles to create a composite matrix resin system. The thermoplastic resin particles (5-50 μm diameter) are dispersed in the thermosetting resin matrix, creating a dual-phase material that leverages the heat resistance of the thermosetting resin while adding the toughness of thermoplastic resin to improve interlayer fracture toughness.
2Ease of manufacture
If reinforced fiber fraction in interlayer region is small, then manufacturing is easier, but stress concentration occurs and compressive strength after impact deteriorates
Solution Approach 1:
The patent applies local quality by specifically enhancing the interlayer region with thermoplastic resin particles while maintaining the overall laminated structure. The particles are concentrated in the interlayer regions where fiber fraction is naturally lower, providing localized toughness enhancement exactly where stress concentration and interlayer fracture are most likely to occur, without compromising the ease of laminating process.
3Adaptability or versatility
If fiber-reinforced composite material has complex three-dimensional curved surface shape, then adaptability is improved, but peeling-off stress in off-plate direction increases and interlayer fracture toughness becomes critical
Solution Approach 1:
The patent changes the physical and chemical parameters of the matrix resin system by incorporating thermoplastic resin particles with specific properties (5-50 μm diameter, melting point 100-200°C). This parameter modification enables the material to maintain structural integrity under the peeling-off stresses generated by complex three-dimensional curved surface geometries, improving mode I and mode II interlayer fracture toughness.
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 solution provides fiber-reinforced composite materials with improved mode I and mode II interlayer fracture toughness, ensuring enhanced compressive strength and resistance to impact, even under complex geometries and varying production conditions.
Implementation Method 1
the component (C) includes polyamide particles and thermosetting polyimide particles... the polyamide particles have a melting point of 140° C to 175° C
Implementation Method 2
the component (C) includes polyamide particles and thermosetting polyimide particles... performing heat molding, and curing the thermosetting resin composition
Data Source
AI summary
A prepreg including: a component (A); a component (B); and a component (C), in which the component (A) is a reinforced fiber substrate, the component (B) is an epoxy resin composition, the component (C) is a component (c1) or a component (c2), the component (c1) includes polyamide particles and thermosetting polyimide particles, and the component (c2) includes spherical polyamide particles having a melting point of 140° C. to 175° C.