Fiber-reinforced composite articles and methods of making them
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Solution Overview
Problem
Thermoset plastics used in fiber-reinforced articles face challenges such as VOC emissions during curing, difficulty in repair or recycling, and high production costs due to complex processing, while thermoplastic resins struggle with infiltration and bonding to fibers, leading to increased complexity and cost in producing fiber-reinforced composite articles.
Innovation Solution
The development of prepregs comprising thermoplastic resin particles in a liquid medium, including polyamide and polyalkylene terephthalate polymers, which are applied to a fiber-containing substrate, treated to form a coated prepreg, allowing for improved bonding and reduced need for additional resin injection, enabling the production of thermoplastic fiber-reinforced articles like automotive and turbine blades with enhanced properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermoset plastics are used for fiber-reinforced articles, then ease of manufacture is improved, but harmful VOC emissions occur during curing and repair/recycling becomes difficult
Solution Approach 1:
The patent changes the fundamental chemical parameters of the resin system from thermoset to thermoplastic polymers. This parameter change eliminates the crosslinking chemistry that causes VOC emissions during curing, while maintaining ease of manufacture through the liquid medium delivery system and controlled solidification process
Solution Approach 2:
The patent utilizes phase transitions of thermoplastic polymers - delivering them in liquid form at elevated temperatures for easy infiltration, then allowing controlled solidification upon cooling. This phase transition approach eliminates the need for exothermic curing reactions that generate VOCs, while maintaining manufacturing simplicity
2Ease of manufacture
If thermoset plastics are used for fiber-reinforced articles, then ease of manufacture is improved, but repair and recycling becomes difficult
Solution Approach 1:
The patent changes the chemical structure from crosslinked thermoset networks to linear or branched thermoplastic chains. This parameter change fundamentally enables repairability through melting and rewelding, while maintaining ease of manufacture through the liquid delivery system
Solution Approach 2:
The patent introduces dynamic reversibility to the material system - thermoplastic polymers can transition between solid and liquid states multiple times through heating and cooling cycles. This dynamic property enables repeated repair and recycling operations, contrasting with the static, irreversible nature of thermoset crosslinking
3Strength
If thermoplastic resins are used to replace thermosets, then fracture toughness and recyclability are improved, but infiltration and bonding to fibers becomes difficult
Solution Approach 1:
The patent introduces a liquid medium as an intermediary carrier that delivers thermoplastic polymer particles to the fiber substrate. This intermediary system solves the infiltration problem by using fluidity to ensure complete wetting and penetration, while the polymer particles maintain their solid-state bonding properties for strong fiber-matrix adhesion
Solution Approach 2:
The patent segments the thermoplastic resin into discrete particles suspended in liquid medium. This segmentation allows the resin to be delivered in a fluid state for easy infiltration, then reassemble into bonded structures upon solidification, combining the benefits of liquid delivery with solid-state mechanical properties
4Adaptability or versatility
If thermoplastic resins are used to replace thermosets, then recyclability is improved, but infiltration and bonding to fibers becomes difficult
Solution Approach 1:
The liquid medium acts as an intermediary that enables complete and uniform delivery of thermoplastic particles to the fiber substrate. This ensures optimal infiltration that facilitates future recycling operations, while the particulate nature of the resin maintains strong bonding capabilities
Solution Approach 2:
The patent performs preliminary action by pre-dispersing and pre-delivering the thermoplastic polymer particles in liquid medium to the fiber substrate before final solidification. This preliminary distribution ensures uniform infiltration and bonding, creating a recyclable composite structure with optimal fiber-matrix interface
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
This method reduces production complexity and costs by ensuring better resin infiltration and bonding, allowing for the creation of high-quality thermoplastic fiber-reinforced articles with improved fracture toughness and recyclability, mitigating environmental impact by facilitating the recycling of thermoplastic parts.
Implementation Method 1
Uncured thermosets are often low viscosity liquids at room temperature and easily wet a fabric of fibers. Once they have migrated through the fabric and surrounded its fibers...
Implementation Method 2
Treatment steps may include removing the liquid medium, for example by evaporation
Implementation Method 3
They may also include heating the combination of substrate and resin particles, and in some instances melting them
Data Source
AI summary
Methods of making prepregs are described. The methods include the steps of forming a fiber-containing substrate, and contacting the fiber-containing substrate with a resin mixture. The resin mixture may include polymer particles mixed in a liquid medium, and the polymer particles may be coated on the fiber-containing substrate to form a coated substrate. The liquid medium may be removed from the coated substrate to form the prepreg. The prepregs may be used to make fiber-reinforced articles.