Vinylidene Fluoride Copolymer End Groups for Dissolution
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Solution Overview
Problem
Vinylidene fluoride copolymers exhibit poor dissolution properties in common organic solvents, requiring long dissolution times at low temperatures for uniform and stable solutions, which is a challenge in preparing electrodes and membranes.
Innovation Solution
A fluoropolymer comprising recurring units derived from vinylidene fluoride and 0.01% to 5% by moles of (meth)acrylic monomers with specific end groups, such as —CF2H and —CF2CH3, is developed, enhancing dissolution properties while maintaining thermal stability, and is manufactured through an aqueous emulsion polymerization process using fluorinated surfactants and perfluoropolyether oils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vinylidene fluoride copolymers comprising recurring units derived from (meth)acrylic monomers are used, then hydrophilic properties and adhesion towards metals are improved, but dissolution properties in common organic solvents deteriorate
Solution Approach 1:
The patent changes the chemical structure parameters of the copolymer by incorporating specific end groups (—CF2H and/or —CF2CH3) in controlled amounts (at least 30 mmoles per Kg of VDF recurring units). This parameter modification enables the copolymer to dissolve in common organic solvents while maintaining the hydrophilic properties and adhesion characteristics provided by the (meth)acrylic monomer units.
2Stability of the object's composition
If long dissolution times are used at low temperatures, then uniform and stable solutions are obtained, but productivity deteriorates
Solution Approach 1:
The patent incorporates specific end groups (—CF2H and/or —CF2CH3) into the copolymer structure during manufacturing as a preliminary action. These pre-incorporated end groups reduce the energy barriers to dissolution, allowing the copolymer to dissolve rapidly in common organic solvents without requiring extended dissolution times, thus maintaining both solution stability and high productivity.
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 polymer exhibits improved dissolution properties and retains good thermal stability, enabling efficient processing as binders for electrodes and membranes, with faster dissolution times and improved processing efficiency.
Implementation Method 1
enhancing dissolution properties in suitable organic solvents
Implementation Method 2
manufactured through an aqueous emulsion polymerization process
Data Source
AI summary
The present invention pertains to a fluoropolymer [polymer (F)] comprising:recurring units derived from vinylidene fluoride (VDF), andfrom 0.01% to 5% by moles of recurring units derived from at least one (meth)acrylic monomer [monomer (MA)] having formula (I) here below:wherein:R1, R2 and R3, equal to or different from each other, are independently selected from a hydrogen atom and a C1-C3 hydrocarbon group, andROH represents a hydrogen atom or a C1-C5 hydrocarbon moiety comprising at least one hydroxyl group,said polymer (F) comprising end groups having formula —CF2H and/or —CF2CH3 in an amount of at least 30 mmoles per Kg of vinylidene fluoride (VDF) recurring units.The invention also pertains to a process for the manufacture of said polymer (F) and to use of said polymer (F) as binders for the manufacture of electrodes or for the manufacture of membranes.