Ligand-Bearing Polymer Fragmentation for Controlled Oxidative Degradation
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Solution Overview
Problem
Existing oxidative degradation methods for polymers, especially in liquid media, are inefficient and can lead to premature degradation during use or result in microplastic formation due to fragile points in the polymer backbone, compromising stability and complete degradation.
Innovation Solution
Incorporating ligands of a reduced metal form, such as citrate or polycarboxylates, into polymer chains enhances oxidative degradation efficiency by increasing radical contact, allowing for fragmentation into smaller, biodegradable species using dioxygen as an oxidant, even in liquid media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If oxidative degradation is used to fragment polymer chains, then degradation efficiency is improved, but polymer stability during use deteriorates
Solution Approach 1:
The patent introduces fragile points (weak groups) into the polymer backbone in advance during synthesis. These fragile points are pre-positioned throughout the polymer structure and remain dormant during normal use. When oxidative degradation is subsequently applied, these pre-introduced fragile points serve as predetermined initiation sites for chain fragmentation, enabling efficient degradation without requiring spontaneous instability during the polymer's service life.
Solution Approach 2:
The patent creates localized weak points (fragile points) within the otherwise stable polymer backbone. These fragile points are specifically positioned at certain locations along the polymer chains and have different chemical properties compared to the rest of the polymer structure. This local differentiation allows the polymer to maintain overall stability during use while providing specific sites that are prone to oxidative degradation, thus achieving both stability and degradability.
2Productivity
If fragile points are introduced in the polymer backbone to enhance degradability, then oxidation efficiency is improved, but polymer stability deteriorates
Solution Approach 1:
The fragile points are introduced during the polymer synthesis process as a preliminary action. These weak groups are built into the polymer backbone structure in advance, allowing the polymer to be synthesized with predetermined degradation sites. During normal use, these pre-positioned fragile points remain stable, but when oxidation is applied, they immediately facilitate efficient degradation without requiring the polymer to be inherently unstable during use.
Solution Approach 2:
The fragile points act as intermediary elements within the polymer structure. These weak groups serve as mediators that connect the stable polymer backbone to the degradation process. They are integrated into the polymer structure and provide a controlled interface where oxidation can initiate chain fragmentation. The fragile points mediate between the stable polymer structure and the oxidative degradation process, enabling efficient oxidation without compromising overall polymer stability during use.
3Ease of operation
If oxidative degradation is applied to polymer in liquid medium, then degradation process is simplified, but degradation efficiency deteriorates
Solution Approach 1:
The patent introduces fragile points into the polymer backbone during synthesis as a preliminary action. These pre-positioned weak groups are distributed throughout the polymer structure and remain stable during normal use in liquid media. When oxidative degradation is subsequently applied, these pre-introduced fragile points serve as predetermined initiation sites that dramatically enhance degradation efficiency, overcoming the inherent inefficiency of oxidizing polymers in liquid media.
Solution Approach 2:
The patent creates localized fragile points within the polymer structure that provide specific sites for oxidative attack. These local weak points are distributed throughout the polymer chains and provide preferential sites for oxidation to initiate. This local differentiation creates regions of high vulnerability within the polymer structure, enabling efficient degradation even in liquid media where the polymer would otherwise be resistant to oxidation.
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 process effectively fragments high-molecular-weight polymers into easier-to-degrade species, reducing environmental impact by enabling biodegradation in natural environments with minimal stability loss during use.
Implementation Method 1
Redox reactions occur implying these two species, which lead to the formation of active radicals, such as hydroxyle radicals •OH, that induce a chain fragmentation
Implementation Method 2
oxidative degradation of a polymer chain contacted with a reduced form of a metal M and an oxidant of the reduced form of metal M, typically dioxygen
Implementation Method 3
Fenton reagent comprising H2O2 and FeSO4.7H2O
Implementation Method 4
the polymer chain comprises chemical groups acting as a ligand of said reduced form of metal M, said groups being covalently bound to the polymer
Data Source
AI summary
The instant invention concerns a process for fragmenting a polymer chain, comprising an oxidative degradation step wherein the polymer chain is contacted with a reduced form of a metal M and an oxidant suh as dioxygen, and wherein the polymer carries covalently bound chemical groups acting as a ligand of said reduced form of the metal M. The invention also relates to methods making use of this fragmentation process as a first step of a degradation process of the polymer especially usefull for avoiding the negative impact of a polymer to the environment. In this connection, the invention relates to the use of polymers carrying chemical groups acting as a ligand for a reduced form of a metal M, as a polymer biodegradable in an environment wherein the reduced form of a metal M is present.