Pre-polymerized Resin Sizing for Composite Recycling
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Solution Overview
Problem
Fiber-reinforced thermoset composites pose health and safety risks due to volatile organic compounds (VOCs) emitted during curing, generate significant unrecyclable waste, and are difficult to repair or modify once cured, especially for larger articles.
Innovation Solution
Treating fibers with a sizing composition containing polymerization compounds and introducing them to a pre-polymerized composition to form a plastic matrix, allowing for the creation of fiber-reinforced composite articles with improved bonding and reduced production challenges, such as high flow viscosities of thermoplastics, through techniques like pultrusion and resin transfer molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uncured thermoset resins are used to make fiber-reinforced composites, then the manufacturing process is simple and inexpensive, but volatile organic compounds (VOCs) are emitted during curing which pose health and safety risks
Solution Approach 1:
The patent changes the chemical parameters of the resin system by using pre-polymerized thermoset resins with controlled gel content (20-90%) instead of uncured resins. This parameter change reduces VOC emissions during processing while maintaining the ease of manufacture through conventional molding techniques.
Solution Approach 2:
The patent utilizes the phase transition properties of pre-polymerized resins that have reached a specific gel point. These resins transition from liquid to semi-solid state during processing, allowing for easy impregnation of fibers before final curing, thus maintaining manufacturing simplicity while reducing harmful emissions.
2Strength
If thermoset polymers are used in fiber-reinforced composites, then the composites have good initial strength, but they cannot be welded or melted for repair or modification once cured
Solution Approach 1:
The patent introduces dynamic characteristics to traditionally static thermoset composites by incorporating uncured or partially cured resin regions that can be reactivated. This allows the composite to transition from a permanently cured state to a reprocessable state, enabling repair and modification while maintaining initial strength through the cured portions.
Solution Approach 2:
The patent applies preliminary action by incorporating polymerization compounds in the sizing composition that remain dormant during initial curing but can be activated later. This allows the composite to be repaired or modified by reactivating the dormant polymerization compounds without compromising the original cured structure.
3Reliability
If high flow viscosity thermoplastics are used to replace thermosets, then fracture toughness and chemical resistance improve, but the resin infiltration and processing become difficult
Solution Approach 1:
The patent changes the viscosity parameter of the resin system by using pre-polymerized thermoset resins with controlled gel content rather than high-viscosity thermoplastics. This maintains good fracture toughness through proper fiber-matrix bonding while achieving lower viscosity for easier resin infiltration and processing.
Solution Approach 2:
The patent uses an intermediary approach by employing sizing compositions containing polymerization compounds that facilitate controlled polymerization during resin infiltration. This intermediary mechanism allows the resin to flow easily during impregnation and then progressively cure to achieve the desired mechanical properties.
4Ease of manufacture
If fiber-reinforced thermoset composites are produced using conventional methods, then production cost is low, but significant unrecyclable waste is generated
Solution Approach 1:
The patent applies discarding and recovering principles by using pre-polymerized resins with controlled gel content that can be processed more efficiently. The reduced VOC emissions and improved process control lead to less waste material and easier recycling of scrap composites, reducing unrecyclable waste while maintaining cost-effectiveness.
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 enables the production of larger, more durable fiber-reinforced composite articles with enhanced fracture toughness and recyclability, reducing waste and VOC emissions, and allowing for repair and recycling of thermoplastic composites.
Implementation Method 1
the pre-polymerized composition polymerizes into a plastic around the fibers
Data Source
AI summary
Methods of making fiber reinforced composite articles are described. The methods may include treating fibers with a sizing composition that includes a polymerization compound, and introducing the treated fibers to a pre-polymerized composition. The combination of the treated fibers and pre-polymerized composition may then undergo a temperature adjustment to a polymerization temperature at which the pre-polymerized composition polymerizes into a plastic around the fibers to form the fiber-reinforced composite article. Techniques for introducing the treated fibers to the pre-polymerized composition may include pultrusion, filament winding, reactive injection molding (RIM), structural reactive injection molding (SRIM), resin transfer molding (RTM), vacuum-assisted resin transfer molding (VARTM), long fiber injection (LFI), sheet molding compound (SMC) molding, bulk molding compound (BMC) molding, a spray-up application, and/or a hand lay-up application, among other techniques.