Fiber-reinforced composites made with multi-part thermoplastic polymers
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Solution Overview
Problem
Fiber-reinforced composite parts made from thermoset plastics are prone to cracking and shattering, while thermoplastic composites have limited mechanical strength due to high melt viscosity, making them challenging to process and repair, and reactive thermoplastic resins face issues like moisture sensitivity and exothermic polymerization.
Innovation Solution
The method involves using a pre-impregnated fiber-containing material with an already-polymerized thermoplastic polymer and introducing reactants for a second reactive thermoplastic resin to the mold, allowing for polymerization and forming a multi-component polymerized thermoplastic resin matrix, which reduces the need for controlling polymerization conditions and manages thermal energy effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermoset polymers are used to make fiber-reinforced composites, then strength and corrosion resistance are improved, but repairability deteriorates and the material becomes prone to cracking and shattering
Solution Approach 1:
The patent changes the chemical parameter of the polymer matrix from thermoset to thermoplastic, which fundamentally alters the material's behavior. Thermoplastics can be melted and reformed, enabling repair of cracks and fractures, while still achieving high strength through optimized fiber reinforcement and processing methods
Solution Approach 2:
The patent uses fiber-reinforced thermoplastic composite materials, combining the high strength of fibers (carbon, glass, or aramid) with the repairability and toughness of thermoplastic matrices. This composite structure maintains strength while adding repair capability
2Ease of repair
If conventional thermoplastic polymer melts are used, then repairability and recyclability are improved, but melt viscosity increases making processing difficult
Solution Approach 1:
The patent changes the temperature parameter during processing, heating the thermoplastic polymer above its melting point to reduce viscosity. This allows the polymer to flow and impregnate fibers effectively during molding, then cools to solidify the composite structure
Solution Approach 2:
The patent uses periodic heating and cooling cycles during processing. The polymer is heated to melt and flow into the mold around fibers, then cooled to solidify and form the final composite part, enabling repeated processing cycles
3Ease of manufacture
If reactive thermoplastic resins are used, then viscosity problems are solved, but moisture sensitivity and exothermic polymerization issues arise
Solution Approach 1:
The patent uses an intermediary substance (such as a coupling agent or surface treatment on fibers) to mediate between the reactive thermoplastic resin and the fiber reinforcement. This intermediary layer protects the fiber surface from moisture-related issues while allowing effective bonding to the polymer matrix
Solution Approach 2:
The patent extracts or removes the problematic moisture-sensitive components from the system, or uses moisture-cure resistant formulations of the reactive thermoplastic resins that are not affected by ambient moisture during processing
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 approach enhances the repairability and recyclability of fiber-reinforced composite articles by reducing the challenges associated with thermoplastic resin processing, such as viscosity and exothermic reactions, and allows for the use of reactive thermoplastic resins that were previously difficult to work with, improving the mechanical properties and processing feasibility of the composites.
Implementation Method 1
reactants for a second reactive thermoplastic resin may be supplied to fill interstitial spaces left by the pre-impregnated material as well as other empty regions of the mold. The mold may then be heated to a polymerization temperature for the second reactive thermoplastic resin to permit the reactants to polymerize and form the fiber-reinforced composite article
Implementation Method 2
The mold may then be heated to a polymerization temperature for the second reactive thermoplastic resin to permit the reactants to polymerize
Data Source
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AI summary
Methods of making fiber reinforced composite articles are described. The methods may include the step of providing a pre-impregnated fiber-containing thermoplastic material to a mold for the article. The pre-impregnated fiber-containing thermoplastic material may include: (i) a plurality of fibers, and (ii) a first thermoplastic polymer made from a first reactive thermoplastic resin. Reactants of a second reactive thermoplastic resin may be introduced to fill open spaces in the mold that are left by the pre-impregnated fiber-containing thermoplastic material. The second reactive thermoplastic resin may then be polymerized to form a second thermoplastic polymer. The final fiber reinforced composite article includes at least two spatially distinct regions of thermoplastic polymer.