Fluorinated Core-Shell Polymer Particles Without Surfactants
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Solution Overview
Problem
The preparation of fluorinated core-shell particles with a high fluorinated polymer shell and non-fluorinated polymer core is challenging due to the need for surfactants and emulsifiers, which complicates the process, reduces fluorine content, and increases costs, while existing methods struggle to produce pure fluorinated particles with desired surface properties.
Innovation Solution
A process involving the synthesis of a non-fluorinated polymer core by aqueous emulsion polymerization, followed by the addition of fluorinated monomers to form a shell without surfactants or emulsifiers, allowing equilibration to ensure no polymerization occurs, and then reacting the shell monomers to create core-shell polymer particles with a high fluorinated polymer content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surfactants and emulsifiers are used in emulsion polymerization to incorporate fluorinated monomers, then the stability and incorporation of fluorinated monomers improve, but the process complexity increases and fluorine content decreases
Solution Approach 1:
The patent removes surfactants and emulsifiers from the polymerization system entirely, using only fluorinated monomers and non-fluorinated comonomers to achieve stable core-shell particles. This extraction of harmful additives resolves the contradiction by eliminating process complexity while maintaining particle stability through controlled polymerization and core-shell architecture.
Solution Approach 2:
The patent creates composite core-shell particles with fluorinated polymer shells and non-fluorinated polymer cores. This composite structure allows the fluorinated shell to provide surface stability and the non-fluorinated core to simplify the overall process by eliminating the need for surfactants, thus resolving the contradiction between stability and process complexity.
2Quantity of substance
If surfactants and emulsifiers are used in emulsion polymerization, then fluorinated monomer incorporation improves, but fluorine content in the final product decreases
Solution Approach 1:
By removing surfactants and emulsifiers from the system, the patent prevents dilution of fluorine content that would otherwise occur through additive incorporation. The fluorinated monomers are incorporated efficiently into the shell structure without being diluted by non-fluorinated additives, thus maintaining high fluorine content while achieving adequate incorporation.
Solution Approach 2:
The patent concentrates fluorinated monomers specifically in the outer shell layer of the particles, creating a localized high-fluorine region. This local quality approach ensures that fluorine is precisely where it is needed for surface properties, maximizing fluorine content in the final product while maintaining effective monomer incorporation.
3Ease of manufacture
If fluorinated particles are prepared using classical emulsion polymerization, miniemulsion polymerization, or microemulsion polymerization, then particle formation is achieved, but the isolation and purification of pure fluorinated particles becomes inefficient
Solution Approach 1:
The patent eliminates the need for complex emulsion systems by using a simplified polymerization approach that produces particles可直接 isolated through filtration. By removing the requirement for emulsifiers and stabilizers, the final product can be easily separated from the reaction medium without complex purification steps, thus resolving the contradiction between ease of manufacture and purification efficiency.
4Reliability
If fluorinated core-shell particles are prepared with high fluorinated polymer shell content, then surface properties improve, but the process becomes more difficult due to poor compatibility and hydrophobicity of fluorinated monomers
Solution Approach 1:
The patent performs preliminary action by first forming a non-fluorinated polymer core, which provides a compatible base structure. This core is then used as a template for subsequent fluorinated monomer polymerization in the shell. This preliminary core formation simplifies the overall process by providing a stable foundation that makes it easier to incorporate hydrophobic fluorinated monomers without requiring complex surfactant systems.
Solution Approach 2:
The patent creates a composite core-shell structure where the non-fluorinated core provides compatibility and ease of manufacture, while the fluorinated shell provides the desired surface properties. This composite approach resolves the contradiction by allowing high fluorinated polymer content in the shell for improved surface properties while the core maintains processability and compatibility.
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 method enables the efficient production of fluorinated core-shell particles with a high fluorinated polymer shell and non-fluorinated polymer core, improving surface properties and reducing costs, allowing for the formation of water-, oil-, and soil-repellent coatings with enhanced durability and chemical resistance.
Implementation Method 1
aqueous emulsion polymerization of non-fluorinated monomers forming the core polymer
Implementation Method 2
due to the poor compatibility and the hydrophobicity of the fluorinated monomers
Data Source
AI summary
Disclosed is a process for preparing fluorinated core-shell polymer particles in which the core is a non-fluorinated polymer and the shell is derived from at least 50% by weight of fluorinated monomers, by 1) synthesizing a core polymer latex by aqueous emulsion polymerization of non-fluorinated monomers forming the core polymer, 2) adding the shell-forming fluorinated monomers or mixtures of at least 50% by weight of fluorinated monomers with non-fluorinated monomers to the core polymer latex of step 1) and allowing for at least one hour of equilibration time in which essentially no polymerization of the shell monomers occurs, 3) reacting the shell-forming monomers in the mixture from step 2) to form the core-shell polymer particles, wherein the process steps 1) to 3) are carried out under mechanical stirring in the absence of surfactants, emulsifiers, emulsifying monomers and mixtures thereof.