Windmill Blade Toughening with Amphiphilic Block Copolymers
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Solution Overview
Problem
Existing methods for producing wind turbine propeller blades using epoxy resin matrices face challenges with high viscosity reactive liquid polymers and preformed particles, which require heating and additional reactive diluents, leading to processing issues and potential reduction in mechanical properties.
Innovation Solution
The use of amphiphilic block copolymers in the epoxy resin matrix, which maintains suitable viscosity at ambient temperature, reduces the need for reactive diluents, and slows down the curing process, allowing complete infusion of the resin into the fiber reinforcement without compromising mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If reactive liquid polymers are used as toughening agents for epoxy resin, then the fracture toughness of the composite is improved, but the viscosity of the resin composition increases significantly, requiring heating and additional reactive diluents for processing
Solution Approach 1:
The patent changes the chemical structure of the toughening agent by using preformed particles (core-shell rubbers, inorganic particles) instead of reactive liquid polymers. These particles provide toughness enhancement without the viscosity increase problem, allowing processing at ambient temperature without requiring additional reactive diluents or heating
Solution Approach 2:
The patent creates a composite toughening system by combining preformed particles with epoxy resin matrix. The preformed particles act as a composite reinforcement within the resin, providing mechanical toughness while maintaining processability. This composite approach allows simultaneous achievement of improved strength and ease of manufacture
2Strength
If preformed particles are used to toughen epoxy resin, then the fracture toughness is improved, but the particles may be filtered out during the infusion process by the fiber matrix, reducing toughness in parts of the composite
Solution Approach 1:
The patent introduces a dispersant as an intermediary substance that facilitates the uniform distribution of preformed particles within the epoxy resin matrix during infusion. The dispersant prevents particle aggregation and ensures consistent particle distribution throughout the composite, preventing filtration by the fiber matrix while maintaining toughness enhancement
Solution Approach 2:
The patent modifies the surface properties of preformed particles through coating or surface treatment to improve their compatibility with the epoxy resin matrix. This parameter change in particle surface characteristics prevents particle filtration during infusion while maintaining their toughness-enhancing function throughout the composite structure
3Ease of manufacture
If reactive diluents are added to reduce the viscosity of the resin composition, then the processing viscosity is improved, but the mechanical properties of the cured composite are reduced
Solution Approach 1:
The patent extracts and eliminates the need for reactive diluents from the resin composition by using preformed particles as toughening agents. The preformed particles provide the necessary toughness enhancement without requiring viscosity-reducing diluents, thereby maintaining mechanical properties while achieving ease of processing at ambient temperature
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 fracture toughness of wind turbine blades while maintaining the glass transition temperature and modulus, ensuring effective penetration of the resin into the fibers and preventing empty spaces, thus improving the structural integrity of the blades.
Implementation Method 1
the liquid toughening agents of the present invention... exhibit a viscosity at ambient temperature that makes them suitable for use in the production of large articles such as windmill blades
Implementation Method 2
the toughening agent will usually slow down the curing process and thus, prevent the viscosity of the composition which is being infused in the fiber reinforcement from increasing too rapidly
Implementation Method 3
the infusion process... the composition will not be able to completely penetrate the interstices of the fibers
Data Source
Figure 1
AI summary
A windmill blade which comprises reinforcing fibers in a toughened resin matrix. The resin matrix is made from a composition which comprises (a) one or more epoxy resins and/or one or more epoxy vinyl ester resins, (b) one or more reactive diluents, and (c) at least one amphiphilic block copolymer. The amphiphilic block copolymer comprises at least two different polyether blocks and is present in the composition in an amount of from about 0.5 % to about 10 % by volume, based on the total volume of the matrix composition.