Glass Fibre Sizing Composition for Polyester Matrix Adhesion
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Solution Overview
Problem
Glass fibre reinforced composites with unsaturated polyester and vinylester matrices exhibit lower mechanical properties compared to those with epoxy matrices, despite similar sizings being used, limiting their structural applications.
Innovation Solution
A silane-based sizing composition for glass fibres comprising at least 15 wt.% dialkoxysilane and 20 wt.% unsaturated ester alkoxysilane, along with a film former and additives, which reduces crosslinking between silane chains, enhancing fibre-matrix adhesion and wetting, thereby improving mechanical properties across various polymeric matrices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional silane-based sizing compositions are used for glass fibres, then interfacial adhesion with epoxy matrix is enhanced, but mechanical properties in polyester and vinylester matrix composites remain substantially lower
Solution Approach 1:
The invention changes the chemical composition parameters of the silane-based sizing by incorporating specific ratios of dialkoxysilane (at least 15 wt.%) and unsaturated ester alkoxysilane (at least 20 wt.%), which fundamentally alters the sizing' performance across different matrix types, enabling comparable mechanical properties in polyester and vinylester composites as in epoxy composites
Solution Approach 2:
The invention creates a universal sizing composition that can be effectively used with multiple types of polymeric matrices (epoxy, polyester, vinylester) without requiring separate sizing formulations for each matrix type, thereby enhancing the adaptability and versatility of the sizing composition
2Reliability
If crosslinking of silane chains is increased to enhance fibre resistance to corrosion, then corrosion resistance is improved, but fibre dispersion and wetting by matrix are compromised
Solution Approach 1:
The invention optimizes the crosslinking density parameter by controlling the ratio and concentration of dialkoxysilane and unsaturated ester alkoxysilane in the sizing composition, achieving a balanced state where sufficient crosslinking provides corrosion resistance while maintaining adequate fibre dispersion and matrix wetting
Solution Approach 2:
The invention uses a composite silane system combining dialkoxysilane and unsaturated ester alkoxysilane with specific film formers and additives to create a multi-functional sizing layer that simultaneously provides corrosion resistance, maintains fibre dispersion, and ensures good matrix wetting
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 proposed sizing composition achieves mechanical properties in polyester and vinylester matrix composites comparable to or exceeding those in epoxy matrix composites, broadening their application spectrum and enhancing resistance to fatigue and corrosion.
Implementation Method 1
silanols obtained by hydrolysing of the alkoxysilanes of the sizing
Implementation Method 2
Si-O-Si covalent bonds can be formed between, on the one hand, the glass fibre surface and silanols
Implementation Method 3
between adjacent silanol groups, thus forming a crosslinked structure at the surface of the glass fibres
Implementation Method 4
Adhesion of the sizing with the matrix is enhanced by the organic function of the silane coupling agent
Data Source
Figure 1
Figure 2(a)~2(b)
AI summary
The present invention concerns a sizing composition for glass fibres comprising : (a) A silane based coupling agent mixture, (b) A film former, (c) Additives, Characterized in that, the silane based coupling agent mixture comprises (d) At least 1 5 wt.% of at least one dialkoxysilane, and (e) At least 20 wt.% of at least one unsaturated ester silane comprising an olefinic double bond activated by an ester function^, Wherein R can be -H, -CH3, -C2H5, wherein R' can be -H„ CH3, -CH2-COOR, wherein R" can be -H, -CH=CH2, -COOH, phenyl, CH3-CH=CH-,-COOR, and wherein m - 0 to 8, preferably 2 to 4, more preferably m = 3, and n = 0 to 2, preferably 0 or 1.