Oligomeric Alkoxyamines for Stable Radical Polymerization
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Solution Overview
Problem
Alkoxyamines used in controlled radical polymerization exhibit low stability and compatibility issues with certain monomers and solvents, leading to incomplete conversion and degradation, which affects the reproducibility of copolymer synthesis.
Innovation Solution
The development of oligomeric alkoxyamines, formed by adding a reduced number of monomeric units to alkoxyamines, enhances stability and reactivity retention over time in the presence of monomers and solvents, maintaining their ability to initiate and control radical polymerization reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional alkoxyamines are used in controlled radical polymerization, then polymerization can be initiated and controlled, but stability deteriorates over time in the presence of monomers and solvents
Solution Approach 1:
The alkoxyamine molecule is segmented by incorporating monomeric units at specific positions (R1 and R2) within its structure. This segmentation allows the molecule to have both the initiating functionality and the stabilizing monomeric segments, resolving the contradiction between initiating capability and stability over time.
Solution Approach 2:
The invention creates a composite molecular structure combining alkoxyamine functionality with monomeric units. This composite structure integrates the initiating properties of alkoxyamines with the stabilizing characteristics of monomeric segments, achieving both polymerization initiation and long-term stability.
2Productivity
If alkoxyamines are left in the presence of monomers for extended periods, then polymerization can proceed, but degradation occurs affecting reproducibility
Solution Approach 1:
The alkoxyamine is pre-modified by incorporating monomeric units during synthesis before being used in polymerization. This preliminary action ensures that the alkoxyamine already possesses the stability features needed for extended storage and handling, preventing degradation that would affect reproducibility.
3Ease of operation
If alkoxyamines are stored in solvents, then handling and processing are facilitated, but kinetic character is lost over time
Solution Approach 1:
The alkoxyamine structure is modified locally by incorporating monomeric units at specific positions (R1 and R2). This local modification provides stability-enhancing features without compromising the kinetic character needed for radical initiation, allowing the molecule to maintain both ease of handling and reactive functionality.
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
Oligomeric alkoxyamines demonstrate improved stability and kinetic consistency, effectively limiting polymerization reactions and maintaining radical initiation capabilities, even in reactive environments, thereby improving the reproducibility and efficiency of polymer synthesis.
Implementation Method 1
Alkoxyamines are molecules which allow the controlled radical polymerization of monomers exhibiting double bonds (vinylic, styrenic, (meth)acrylic, etc.)
Data Source
AI summary
A new class of alkoxyamines, exhibiting improved stability on storage, especially in the presence of monomers and/or of solvent is described, particularly where the alkoxylamines are a new class of oligomeric alkoxyamines, which are obtained by addition of one or more monomeric entities to an alkoxyamine.