Emulsion Polymerization of 1,1-Disubstituted Alkenes
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Solution Overview
Problem
The polymerization of 1,1-disubstituted alkene compounds using anionic polymerization is challenging due to difficulties in controlling the structure and properties of the resulting polymers, particularly in bulk polymerization, where high viscosity and temperature spikes occur, and emulsion polymerization is hindered by reactivity with water and surfactants, leading to issues like particle aggregation and undesirable by-products.
Innovation Solution
An emulsion polymerization process is developed involving agitation of a mixture with a carrier liquid and surfactant to form micelles, followed by anionic polymerization initiated with an activator, allowing for controlled polymerization of 1,1-disubstituted alkene monomers to achieve specific molecular weights and sequence distributions, and the use of an acid-containing compound to stabilize the emulsion and control reaction rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If bulk polymerization is used to polymerize 1,1-disubstituted alkene compounds, then high molecular weight polymer is produced, but the polymer exhibits high viscosity and difficult handling
Solution Approach 1:
The patent applies segmentation by dividing the bulk polymerization process into multiple controlled stages with sequential monomer additions. This allows the polymerization to proceed in manageable increments, controlling viscosity at each stage while building up molecular weight over time, thereby maintaining ease of handling throughout the process.
Solution Approach 2:
The patent employs dynamic control of polymerization conditions by adjusting temperature, addition rates, and catalyst concentrations during the process. This dynamic approach allows optimization of molecular weight growth while controlling viscosity increases, ensuring the polymer remains handleable throughout production.
2Productivity
If bulk polymerization is used to achieve high conversion, then polymer yield increases, but temperature spikes occur during the process
Solution Approach 1:
The patent implements periodic action through staged monomer addition and controlled reaction intervals. By adding monomers in stages and allowing controlled reaction periods between additions, the exothermic heat generation is distributed over time rather than occurring all at once, preventing temperature spikes while maintaining high overall yield.
Solution Approach 2:
The patent maintains continuous useful action through optimized reaction conditions and staged additions that keep the polymerization proceeding efficiently without interruption. This continuous controlled process achieves high conversion and yield while managing heat generation through sustained, controlled reaction rather than intermittent high-intensity reactions.
3Manufacturing precision
If emulsion polymerization is used to improve process control, then polymer structure control improves, but reactivity with water and surfactants causes particle aggregation and by-products
Solution Approach 1:
The patent uses an intermediary approach by selecting and optimizing specific surfactant types and concentrations that mediate between the hydrophobic monomer/polymer and the aqueous phase. This carefully chosen intermediary prevents direct harmful reactions while maintaining emulsion stability and preventing particle aggregation, allowing structure control benefits to be realized.
Solution Approach 2:
The patent applies parameter changes by optimizing pH, ionic strength, surfactant concentration, and temperature to minimize reactivity between the 1,1-disubstituted alkene and water/surfactant components. By carefully controlling these parameters, the system achieves good polymer structure control while suppressing harmful side reactions and aggregation.
4Productivity
If bulk polymerization is used for manufacturing large quantities, then production scale increases, but heat transport issues and shear heat generation occur
Solution Approach 1:
The patent applies segmentation to large-scale manufacturing by dividing the total monomer charge into multiple staged additions. This allows the reaction heat to be generated and removed in manageable increments rather than all at once, solving heat transport issues while maintaining high overall production throughput through efficient use of reactor capacity.
Solution Approach 2:
The patent employs dynamic control of large-scale polymerization by adjusting addition rates, agitation speeds, and temperature setpoints based on real-time reaction conditions. This dynamic optimization allows efficient heat management in large reactors while maintaining high productivity through maximized reactor utilization.
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 process enables the production of polymers with improved molecular weight control, reduced polydispersity, and controlled viscosity, facilitating the production of high-quality emulsions suitable for applications like paints and coatings, with the ability to scale up to larger reactors and higher throughput.
Implementation Method 1
reacting an activator with at least one of the first monomers in the micelle for initiating the anionic polymerization of the one or more first monomers
Implementation Method 2
agitating a mixture comprising: 25 weight percent or more of a carrier liquid, a surfactant, and one or more first monomers to form micelles of the one or more monomers in the carrier liquid
Data Source
Figure 1~2
Figure 3A~3B
Figure 4
AI summary
The present teachings show that it is possible to polymerize 1,1-disubstituted alkene compounds in an emulsion (for example using a water based carrier liquid), despite the possible reactions between the monomer and water. Polymerization of 1,1-disubstituted alkene compounds in an emulsion provides opportunities to better control the polymerization compared with bulk polymerization. The emulsion polymerization techniques can be employed for preparing homopolymers, copolymers (e.g., random copolymers), and block copolymers.