High Heat Epoxy Composition with Core-Shell Particles
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Solution Overview
Problem
Cured epoxy polymers are brittle and lack toughness, and attempts to increase toughness often result in high viscosities that hinder processibility, necessitating a need for epoxy resins with improved processibility and increased fracture toughness.
Innovation Solution
A curable high heat epoxy composition comprising 40-95 wt% high heat diepoxy compound, 1-40 wt% auxiliary polyepoxide, 0.01-12 wt% core-shell particles with an elastomer core and rigid shell, and a hardener, which can be cured to achieve a fracture toughness of greater than 250 J/m² and a glass transition temperature of 200-270°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If attempts are made to increase toughness of cured epoxy polymers, then fracture toughness is improved, but viscosity increases and processibility deteriorates
Solution Approach 1:
The patent employs a composite material system combining high heat diepoxy compounds (formulas I-X), auxiliary polyepoxide, core-shell particles with elastomer cores and rigid shells, and hardeners. This composite approach allows the elastomer core to provide toughness while the rigid shell maintains structural integrity and prevents excessive viscosity increase, resolving the contradiction between improving fracture toughness and maintaining processibility
Solution Approach 2:
The core-shell particles exhibit local quality differentiation where the elastomer core provides localized toughness and energy absorption during fracture, while the rigid shell maintains overall structural rigidity and controls viscosity. This localized functional differentiation allows the material to achieve high fracture toughness without sacrificing processibility
2Ease of manufacture
If conventional epoxy formulations are used, then processibility is maintained, but fracture toughness remains low and brittleness increases
Solution Approach 1:
The invention introduces core-shell particles with elastomer cores into the conventional epoxy formulation. The elastomer core acts as a stress concentrator and energy absorber during fracture, significantly improving toughness while the particle's small size and shell structure prevent excessive viscosity increase, maintaining processibility
Solution Approach 2:
The patent modifies the epoxy system by incorporating specific ratios of high heat diepoxy compounds (40-95 wt%), auxiliary polyepoxide (1-40 wt%), and core-shell particles (0.01-12 wt%). These parameter changes optimize the balance between toughness enhancement and viscosity control, allowing conventional processing methods to remain effective while achieving superior mechanical properties
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 composition achieves a significant increase in fracture toughness and maintains a low melt viscosity, enhancing the processibility and mechanical properties of the cured epoxy thermosets while maintaining desirable thermal resistance.
Implementation Method 1
a core-shell particle comprising an elastomer core and a rigid shell
Implementation Method 2
core-shell particle comprising an elastomer core and a rigid shell
Implementation Method 3
Epoxy thermosets are generally formed from a mixture of one or more multifunctional epoxide compounds, which react with a hardening agent
Implementation Method 4
This reaction allows for the growth of linear molecular weight of the polymer. The polymer thus formed can be cast into a specific shape and permanently hardened (cured)
Implementation Method 5
The curable composition can have a melt viscosity of less than 200 Pascal-seconds (Pa·s)
Implementation Method 6
a cured product derived from the composition can have a fracture toughness of greater than 250 Joules per square meter (J/m²)
Implementation Method 7
desirable thermal resistance
Data Source
AI summary
A curable high heat epoxy composition, comprising: 40 to 95 weight percent (wt%), preferably 50 to 90 wt%, more preferably 55 to 80 wt% of at least one high heat diepoxy compound of formulas (I) to (X), wherein R1, R2, R13, R14, Ra, Rb, Rg, p, q, c, and t are as provided herein; 1 to 40 weight percent, preferably 5 to 30 wt%, more preferably 8 to 20 wt%of an auxiliary polyepoxide; 0.01 to 12 wt%, preferably 0.1 to 10 wt%, more preferably 1 to 8 wt% of a core-shell particle comprising an elastomer core and a rigid shell; and a hardener.