pH-Responsive Functional Monomer for Room Temperature Emulsion Polymerization
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Solution Overview
Problem
Conventional reactive emulsifiers, particularly cationic-type, face challenges in polymerization at room temperature due to complex synthesis conditions and poor reducing properties, requiring additional emulsion breakers for stabilization, which complicates the emulsion polymerization process.
Innovation Solution
Development of an H+/OH− responsive functional monomer that adjusts its role as an emulsifier, polymerizing monomer, reducing agent, or emulsion breaker based on pH, allowing for stable emulsion polymerization at room temperature without the need for additional breakers, using structures like 2-(tetradecyl ester) dimethylaminoacetamide maleate (TDMAMA) and 2-(tetradecyl ester) dimethylaminoacetamide itaconic acid (TDMAIA).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional cationic-type reactive emulsifiers are used, then emulsion stability is improved, but polymerization at room temperature becomes difficult and synthesis conditions become complex
Solution Approach 1:
The patent introduces a pH-responsive functional monomer that changes its properties based on pH conditions. At low pH, the monomer acts as a reactive emulsifier with good reducing properties, enabling room temperature polymerization. At high pH, it functions as a conventional emulsifier for stability. This parameter-based transformation resolves the contradiction between emulsion stability and polymerization ease.
Solution Approach 2:
The functional monomer is designed to perform multiple roles: it can act as a reactive emulsifier, a polymerizing monomer, and a reducing agent depending on the pH conditions. This multi-functionality eliminates the need for separate additives and simplifies the overall process while maintaining both emulsion stability and polymerization feasibility.
2Stability of the object's composition
If conventional emulsifiers are used, then emulsion stability is achieved, but additional emulsion breakers are required and the process becomes more complex
Solution Approach 1:
The pH-responsive functional monomer serves itself by automatically adjusting its function based on pH conditions. During polymerization, it provides both emulsion stability and reducing properties. After polymerization, by simply adjusting pH, it enables emulsion breaking without requiring additional breakers. This self-service capability reduces process complexity.
Solution Approach 2:
The patent combines the functions of emulsifier, polymerizing monomer, reducing agent, and emulsion breaker into a single pH-responsive functional monomer system. This merging of multiple functions into one component simplifies the overall process and eliminates the need for multiple separate additives.
3Use of energy by moving object
If room temperature polymerization is implemented, then energy consumption is reduced, but polymerization reaction becomes difficult with conventional emulsifiers
Solution Approach 1:
The functional monomer's reducing properties are activated at low pH conditions, which enables it to function as an effective reducing agent at room temperature. This parameter change (pH control) allows the polymerization reaction to proceed reliably at lower temperatures without requiring high energy input, thus resolving the contradiction between energy consumption and polymerization reliability.
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
Enables high molecular weight polymer production with a branched structure and improved emulsion stability, facilitating a simple and energy-efficient emulsion polymerization process with high conversion rates, and allowing for the regulation of emulsion polymerization through pH adjustments.
Implementation Method 1
regulates an H/OH content by introducing acid and alkali solutions, and regulates its different functions in the emulsifier, polymerizing monomer, reducing agent, emulsion breaker, etc. at different pH
Implementation Method 2
the polymerizable surfactant has excellent emulsifying properties when a pH of the polymerizable surfactant is weakly alkaline, and can also act as a reducing agent to participate in a redox initialization reaction
Implementation Method 3
the reactive emulsifier is bonded to the surface of emulsion particles in the form of covalent bonds and is not easily affected by the external force
Implementation Method 4
it is necessary to add an additional emulsion breaker when breaking the emulsion... the emulsion obtained after the polymerization reaction is very stable, and it is necessary to add an additional emulsion breaker when breaking the emulsion
Data Source
AI summary
The present disclosure discloses a method of a functional monomer in emulsion polymerization, belonging to the field of synthesis of functional monomers and methods of emulsion polymerization. The present disclosure obtains functional monomers TDMAMA and TDMAIA by synthesis, which may show different functions at different pH. By adjusting an H+/OH− content in an emulsion with an acid and alkali solution at a certain concentration, it is found that the functional monomers are both an emulsifier, a polymerizing monomer, and a reducing agent at a specific pH, at which the emulsion is stable, and may perform free-radical emulsion polymerization at room temperature, and high molecular weight polymer is obtained through a branched polymerization. When an H+ concentration is less than OH−, the emulsion is unstable and has flocculation, then the polymerization terminates, and emulsion breaking can be realized without adding an additional emulsion breaker.