Sizing composition for reinforcing fibres and applications thereof
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Solution Overview
Problem
Existing methods for improving the adhesion between reinforcing fibers and organic matrices polymerized by light radiation or ionizing radiation, such as chain transfer mechanisms, are insufficient, leading to mediocre transverse mechanical properties in composite materials.
Innovation Solution
A sizing composition comprising a polybutadiene prepolymer with epoxy functions, a cross-linking agent with thiol functions, and a tertiary amine catalyst is applied to the fibers, forming a homogeneous elastomer film that enhances adhesion by catalyzing reactions and acting as chain transfer agents during polymerization, thereby improving the bond between fibers and the organic matrix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional sizing agents or surface treatments are used, then fiber handling and protection are improved, but adhesion to matrices polymerized by chain transfer mechanisms remains insufficient
Solution Approach 1:
The patent introduces a specific sizing composition containing thiol-functionalized silane compounds as intermediary substances between the fiber surface and the chain transfer polymerized matrix. The silane compounds with thiol groups (such as γ-methacryloxypropyltrimethoxysilane combined with mercaptan compounds) act as mediators that can participate in chain transfer polymerization, creating covalent bonds with the matrix while adhering to the fiber surface, thus resolving the adhesion insufficiency problem.
Solution Approach 2:
The patent modifies the chemical parameters of the sizing agent by incorporating specific functional groups (thiol and methacrylate groups) that are compatible with chain transfer polymerization mechanisms. This parameter change in the sizing composition's chemical structure enables it to actively participate in the polymerization process rather than merely providing passive coating, thereby improving adhesion reliability.
2Strength
If complex chemical or electrolytic oxidation treatments are applied to fiber surfaces, then functional groups for chemical reaction are created, but the adhesion to matrices polymerized by light or ionizing radiation remains insufficient
Solution Approach 1:
The patent changes the chemical parameters of the fiber surface treatment by applying thin film coatings containing thiol-functionalized silane compounds instead of traditional oxidation treatments. This parameter change shifts from creating oxygen-containing functional groups to introducing sulfur-containing thiol groups and polymerizable methacrylate groups, which are specifically compatible with chain transfer, light, and ionizing radiation polymerization mechanisms.
Solution Approach 2:
The patent creates a composite sizing structure combining silane compounds with thiol and methacrylate functional groups on the fiber surface. This composite chemical structure integrates both surface adhesion properties and chain transfer polymerization participation capability, enabling effective bonding with matrices polymerized by light or ionizing radiation.
3Ease of manufacture
If traditional sizing agents are used, then fiber protection and handling are achieved, but transverse mechanical properties of the composite material are mediocre
Solution Approach 1:
The patent introduces thiol-functionalized silane compounds as intermediary substances that actively participate in the polymerization process. These intermediaries form covalent bonds with the matrix through chain transfer mechanisms, creating strong interfacial adhesion that significantly improves transverse mechanical properties such as shear strength and interlaminar shear strength.
Solution Approach 2:
The patent creates a composite sizing system combining silane base structures with thiol and methacrylate functional groups. This composite chemical structure provides both protective coating functions and active participation in polymerization, resulting in enhanced interfacial bonding and improved transverse mechanical properties of the composite material.
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 solution significantly increases the adhesion between reinforcing fibers and the organic matrix, enhancing the transverse mechanical properties of composite materials, particularly when used with resins polymerized by chain transfer mechanisms.
Implementation Method 1
a catalyst comprising at least one tertiary amine function
Implementation Method 2
a cross-linking agent comprising at least two reactive functions, at least one of which is a thiol function
Implementation Method 3
adhesion between these fibres and an organic matrix forming with them a part made of a composite material and resulting from the chain transfer polymerization of a curable resin
Data Source
AI summary
A sizing composition for reinforcing fibres is provided which makes it possible to improve the adhesion of these fibres with respect to an organic matrix that forms, with them, a part made of a composite material and that results from the chain transfer polymerization of a curable resin. The sizing composition includes a polybutadiene prepolymer comprising at least two epoxide functions, a cross-linking agent comprising at least two reactive functions, at least one of which is a thiol function; and a catalyst comprising at least one tertiary amine function. The sizing composition may be used in the following fields of use: aeronautical, aerospace, railway, naval and motor vehicle industries, for example, for the production of structural, engine, passenger compartment or body work parts; arms industry, for example, for the production of parts incorporated into the composition of missiles or missile launch tubes; sports and leisure goods industry, for example, for the production of goods intended for water sports and board sports.