Epoxy Resin Composition Impact Strength
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Solution Overview
Problem
Epoxy resins exhibit low mechanical resistance, particularly to peel and impact stresses, due to their hard and brittle nature, which limits their effectiveness in applications requiring enhanced impact strength.
Innovation Solution
A polymeric composition combining epoxy resin with a reactive copolymer having a glass transition temperature of −20° C. or less and nanoparticles of 5 to 150 nm in size, forming rubber domains and interpenetrating networks that significantly improve mechanical properties such as fracture toughness and impact strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If epoxy resin is used to provide structural integrity and chemical resistance, then strength and chemical resistance are improved, but impact strength and mechanical resistance deteriorate due to brittleness
Solution Approach 1:
The patent applies composite materials by combining epoxy resin with a copolymer modifier (such as carboxyl-functional butadiene-acrylonitrile rubber) to create a modified epoxy resin composition. This composite structure allows the brittle epoxy matrix to incorporate flexible copolymer phases that absorb impact energy through deformation, thereby improving impact strength while maintaining the structural integrity and chemical resistance of the epoxy resin.
2Strength
If copolymer modification is applied to improve impact strength, then fracture toughness is improved, but the complexity of the composition increases
Solution Approach 1:
The patent applies parameter changes by carefully controlling the glass transition temperature (Tg) of the copolymer modifier, specifying it should be between -50°C and -20°C. This parameter optimization ensures the copolymer provides adequate flexibility and impact resistance at service temperatures while maintaining proper curing characteristics and composition manageability. The specific Tg range balances mechanical property enhancement with practical formulation considerations.
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 combination of copolymers and nanoparticles creates a synergistic effect, resulting in thermosets with improved mechanical properties like strength, heat distortion resistance, and chemical resistance, while maintaining other important characteristics unaffected.
Implementation Method 1
Within these rubber domains it is possible essentially for only van der Waals forces to act, for example, between the copolymer molecules
Implementation Method 2
The copolymer provided in accordance to the invention must possess reactive groups that are able to react with the epoxy groups of the epoxy resin and so bind the copolymer chemically into the epoxy resin
Implementation Method 3
a) at least one epoxy resin, b) at least one copolymer having groups that are reactive toward epoxy resins and having a glass transition temperature Tg of −20° C. or less, c) nanoparticles having an average particle size dmax as measured by means of small-angle neutron scattering (SANS) of 5 to 150 nm
Data Source
AI summary
The invention relates to a polymeric composition containing: a) at least one epoxy resin; b) at least one copolymer with groups, which react with epoxy resins, and with a glass transition temperature Tg of −20° C. or lower, c) nanoparticles having a mean particle size dmax ranging from 5 to 150 nm that is measured by means of a small-angle neutron scattering (SANS). The inventive composition enables the production of adhesives, composite materials, coatings and casting compounds exhibiting improved mechanical properties, particularly improve impact strength.