Perforated Prepregs for Composite Gas Removal
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Solution Overview
Problem
The consolidation of fiber-reinforced composites is hindered by trapped gases within prepregs, which are difficult to remove due to the matrix inhibiting gas movement, leading to porosity and reduced mechanical properties in the composite.
Innovation Solution
Perforated prepregs with dimensionally stable perforations are introduced to provide routes for gas escape, allowing for enhanced removal of trapped gases during consolidation, thereby reducing porosity and improving mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the matrix resin is used to surround and bind fibers in prepregs, then the structural integrity and cohesion of the composite is improved, but gas movement is inhibited and trapped gases cannot escape during consolidation
Solution Approach 1:
The patent introduces a porous PTFE coating on the prepreg surface that maintains structural integrity while providing gas permeability. The porous structure allows trapped gases to escape during consolidation without compromising the binding function of the matrix resin, thus resolving the contradiction between structural integrity and gas removal capability
Solution Approach 2:
The PTFE coating acts as an intermediary layer between the matrix resin and the external environment. It mediates the conflict by allowing gas molecules to pass through while maintaining the structural cohesion provided by the matrix, enabling gas removal without sacrificing structural integrity
2Object-generated harmful factors
If vacuum pressure is applied to remove trapped gases from prepregs, then gas removal is enhanced, but the process time is extended and complete removal is difficult to achieve
Solution Approach 1:
The porous PTFE coating is applied in advance to the prepreg surface before consolidation. This preliminary action creates pre-established gas escape pathways, so that when vacuum pressure is applied during consolidation, gases can escape rapidly through the pre-formed porous structure without requiring extended process time
Solution Approach 2:
The porous PTFE coating provides numerous micro-channels that facilitate rapid gas escape. When vacuum pressure is applied, gases can simultaneously escape through multiple pathways in the porous structure, dramatically reducing the time required for complete gas removal compared to conventional dense coatings
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 use of perforated prepregs results in composites with porosity less than 10 vol.%, significantly reducing voids and enhancing the mechanical properties of the composite structures.
Implementation Method 1
a porous coating comprising a porous PTFE material is present on at least a portion of the fibers
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3A
AI summary
Systems and methods for the fabrication of prepregs possessing enhanced ability for the removal of gases from within prepregs and prepreg layups prior to and/or during at least a portion of consolidation and cure process to form composite structures are disclosed. In certain embodiments, perforations of selected configurations may be introduced into the prepregs prior to, during, and after layup. The perforations provide routes for gases trapped within and between the perforated prepregs and prepreg lay-ups to escape during consolidation and cure process, reducing the residual porosity within the resulting composite. For example, composites having residual porosities less than 10 vol. %, on the basis of the volume of the composite, may be achieved in this manner.