Epoxy Resin Composition Toughening with Segmented Poly(aryl ether sulfone)
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Solution Overview
Problem
High molecular weight functionalized poly(aryl ether sulfone)s toughened epoxy resin compositions exhibit high viscosity, making it difficult to process and cure, limiting their use in applications requiring high strength, damage tolerance, and toughness, such as aerospace composites.
Innovation Solution
A composition comprising 30-90% epoxy compound, 0-60% curing agent, 0-15% accelerator, and 1-60% poly(aryl ether sulfone) polymers with specific amine functional groups, which combines two different poly(aryl ether sulfone) polymers to enhance processability without compromising mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high molecular weight functionalized poly(aryl ether sulfone)s are used to toughen epoxy resin, then strength, damage tolerance and toughness are improved, but viscosity increases making processing and curing difficult
Solution Approach 1:
The patent divides the single polymer component into two distinct poly(aryl ether sulfone) polymers with different molecular weights and functional group concentrations. The first polymer provides high strength and toughness, while the second polymer maintains lower viscosity for easier processing. This segmentation allows each component to fulfill specific functions that collectively resolve the contradiction between strength enhancement and processability.
Solution Approach 2:
The patent changes the parameters of the poly(aryl ether sulfone) polymers by selecting specific molecular weights and functional group concentrations. The first polymer has higher molecular weight and functional group concentration for strength, while the second polymer has lower molecular weight and functional group concentration for viscosity control. This parameter optimization resolves the contradiction by tuning the physical and chemical properties of the polymers.
2Strength
If high molecular weight functionalized poly(aryl ether sulfone)s are used to improve damage tolerance and toughness, then fracture toughness is improved, but resin viscosity increases affecting wetting of carbon fiber matrix
Solution Approach 1:
The patent segments the polymer system into two components where the second poly(aryl ether sulfone) polymer with lower molecular weight and functional group concentration specifically addresses the wetting issue. This lower viscosity component can more effectively penetrate and wet the carbon fiber matrix during processing, while the first polymer maintains the fracture toughness requirements.
Solution Approach 2:
The second poly(aryl ether sulfone) polymer acts as an intermediary that facilitates the wetting process between the epoxy resin and carbon fiber matrix. Its lower viscosity and molecular weight enable it to serve as a flow medium that improves resin infiltration and fiber wetting, while the first polymer provides the structural integrity and fracture toughness.
3Reliability
If high molecular weight functionalized poly(aryl ether sulfone)s are used to achieve high temperature performance and solvent resistance, then thermal and chemical resistance are improved, but curability characteristics deteriorate
Solution Approach 1:
The patent segments the curing function between two polymers: the first high molecular weight polymer provides thermal performance and structural stability, while the second lower molecular weight polymer with fewer functional groups enables better curability characteristics. This segmentation allows the curing process to proceed more effectively without compromising the high temperature performance provided by the first polymer.
Data Source
AI summary
An epoxy resin composition [composition (C)] comprising: (i) from 30 to 90% by weight of at least one epoxy compound [compound E], based on the total weight of the composition (C); (ii) from 0 to 60% by weight of at least one curing agent [agent C], based on the total weight of the composition (C); (iii) from 0 to 15% by weight of at least one accelerator, based on the total weight of the composition (C); (iv) from 1 to 60% by weight of at least one poly(aryl ether sulfone) (I) [PAES (I-1)], based on the total weight of the composition (C) and wherein said PAES (I-1) polymer comprises amine functional groups in an amount equal to or more than 200 μeq/g; (v) from 1 to 60% by weight of at least one poly(aryl ether sulfone) (I) [PAES (I-2)], based on the total weight of the composition (C), and wherein said PAES (I-2) polymer is different from the PAES (I-1) polymer.