Contaminated Polymer Depolymerization with Trapping Agents
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Solution Overview
Problem
Existing depolymerization processes for recycling plastics, such as poly(methyl methacrylate) (PMMA), struggle to effectively reduce the concentration of contaminants like pigments, plasticizers, and degradation products, which can lead to contamination of the resulting monomers and pose environmental and health risks.
Innovation Solution
The introduction of one or more trapping agents during the depolymerization process, which interact with contaminants to immobilize or degrade them, allowing for their separation from the monomers. These trapping agents can include dolomite, diatomaceous earth, metal oxides, and supported peroxides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional depolymerization processes are used to recycle PMMA, then the process is simple and energy-efficient, but the concentration of contaminants (pigments, plasticizers, degradation products) in the resulting monomers remains high
Solution Approach 1:
The patent introduces trapping agents as intermediary substances that mediate between the contaminants and the depolymerization process. These agents (such as metal oxides, activated carbon, or molecular sieves) selectively capture contaminants like pigments, plasticizers, and degradation products, allowing the monomers to be recovered with high purity without requiring complex additional separation equipment
Solution Approach 2:
The patent modifies the depolymerization process by changing parameters such as temperature profiles, residence time, and the addition of trapping agents. By optimizing these parameters, the process achieves both high monomer purity and reasonable process complexity, resolving the contradiction between manufacturing precision and device complexity
2Productivity
If high temperature pyrolysis is used to depolymerize PMMA, then the depolymerization efficiency is high, but contaminants are released and contaminate the crude MMA
Solution Approach 1:
The patent converts the harmful effect of high temperature (which releases contaminants) into a beneficial process by introducing trapping agents that capture these contaminants. The high temperature continues to provide efficient depolymerization, while the trapping agents transform the harmful contaminant release into a controlled capture mechanism, ultimately improving monomer purity
Solution Approach 2:
Trapping agents serve as intermediaries between the high temperature pyrolysis process and the crude MMA product. These agents (such as metal oxides or activated carbon) intercept contaminants released during high-temperature depolymerization, preventing them from contaminating the monomer while allowing the efficient high-temperature process to continue
3Reliability
If polyethylene protection film is present with PMMA, then the plastic provides necessary protection, but polyethylene degrades at higher temperature and generates long chain oligomers that decrease the quality of recovered crude MMA
Solution Approach 1:
The patent extracts or removes the harmful polyethylene degradation products from the system by using trapping agents that selectively capture long chain oligomers and waxes. This allows the polyethylene protection film to fulfill its protective function while its degradation products are removed before they can contaminate the recovered MMA monomers
Solution Approach 2:
Trapping agents act as intermediaries that selectively interact with polyethylene degradation products (long chain oligomers and waxes) without interfering with the PMMA depolymerization. This mediation allows the protection film to remain functional while its harmful degradation products are captured and removed from the monomer recovery stream
4Adaptability or versatility
If EVA copolymer is used as PVC replacement, then the plastic provides necessary functionality, but EVA decomposes into acetic acid and hydrocarbon oligomers that generate corrosion and decrease monomer quality
Solution Approach 1:
The patent converts the harmful corrosion and contamination effects of EVA decomposition into a manageable process by using trapping agents to capture acetic acid and hydrocarbon oligomers. The EVA copolymer continues to provide its functional replacement capability, while its degradation products are transformed from harmful contaminants into captured substances that can be easily removed
Solution Approach 2:
Trapping agents serve as intermediaries that selectively capture EVA degradation products (acetic acid and hydrocarbon oligomers) without interfering with the functional performance of the EVA copolymer during depolymerization. This mediation allows EVA to fulfill its replacement function while its harmful decomposition products are intercepted and removed
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 use of trapping agents significantly reduces the concentration of contaminants in the resulting monomers, improving the quality of the recycled products, reducing environmental risks, and facilitating proper waste management.
Implementation Method 1
contacting at least one solid trapping agent with the contaminated polymers to be depolymerized... whereby the non-PET and non-PVC contaminants interact with the solid trapping agents
Implementation Method 2
depolymerizing the polymers leading to corresponding monomers
Data Source
AI summary
The present invention concerns an improved depolymerization process of contaminated polymers such as PMMA, comprising the separation of contaminants from the resulting monomers, by using appropriate agents for trapping the contaminants.