Plastic Product Amorphization for Unsorted Enzymatic Depolymerization
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Solution Overview
Problem
Existing plastic recycling processes require extensive sorting and are inefficient for mixed polymer plastics, leading to high costs and non-competitive recycled products.
Innovation Solution
A process involving amorphization and depolymerization steps to degrade plastic products, specifically targeting semi-crystalline thermoplastic polyesters like PET and PLA, by heating above the melting temperature and cooling below the crystallization temperature, followed by biological depolymerization with enzymes such as cutinases and lipases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If plastic recycling processes use extensive sorting and conventional methods, then recycling accuracy is improved, but processing cost increases and productivity decreases
Solution Approach 1:
The invention changes the physical state parameter of the plastic from crystalline to amorphous by controlling cooling rates, which fundamentally alters the plastic's susceptibility to enzymatic degradation. This parameter change enables direct processing of mixed plastics without sorting, as the amorphous state makes all plastics equally accessible to depolymerases, resolving the contradiction between recycling accuracy and processing efficiency
Solution Approach 2:
The invention introduces an intermediary step (amorphization) between plastic collection and depolymerization. This intermediary process converts all mixed plastics into a uniform amorphous state that serves as a common substrate for depolymerases, eliminating the need for prior sorting while maintaining effective degradation, thus improving both recycling accuracy and productivity
2Manufacturing precision
If plastic recycling processes require extensive sorting, then polymer purity is improved, but device complexity and processing cost increase
Solution Approach 1:
The invention extracts the crystalline structure from the plastic through rapid cooling to create an amorphous state. This extraction of crystallinity removes the structural feature that necessitates sorting, as amorphous plastics of different types all present similar characteristics to depolymerases, thereby simplifying the processing system while maintaining effective recycling
Solution Approach 2:
The invention performs a preliminary amorphization action on all mixed plastics before depolymerization. This preliminary transformation creates a uniform starting material that eliminates the need for complex sorting systems, as the amorphous state standardizes the physical properties of diverse plastics, reducing device complexity while preserving polymer purity through selective enzymatic degradation
3Ease of manufacture
If conventional depolymerization is applied to crystalline plastics, then process simplicity is maintained, but degradation efficiency is insufficient
Solution Approach 1:
The invention applies a preliminary amorphization action before depolymerization to transform crystalline plastics into an amorphous state. This preliminary step dramatically enhances degradation efficiency by making the polymer chains accessible to depolymerases, while the overall process remains relatively simple, requiring only temperature and cooling rate control followed by standard enzymatic treatment
Solution Approach 2:
The invention exploits the phase transition from crystalline to amorphous state through controlled cooling. This phase transition fundamentally changes the plastic's molecular arrangement from ordered to disordered, making it highly susceptible to enzymatic attack. The phase transition approach maintains process simplicity while achieving high degradation efficiency, as it uses fundamental physical changes rather than complex chemical modifications
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
Achieves high-level degradation of plastic products without sorting, producing monomers and oligomers efficiently under industrial conditions, reducing environmental impact and recycling costs.
Implementation Method 1
submitting the plastic product to a temperature above the melting temperature (Tm) of said semi-crystalline thermoplastic polyester
Implementation Method 2
cooling the plastic product by submitting the plastic product to a temperature below the crystallization temperature (Tc) of said semi-crystalline thermoplastic polyester less than 1 min after the heating phase
Implementation Method 3
Depolymerizing said at least partially amorphized polyester of the plastic product by contacting the plastic product with a depolymerase able to depolymerize said at least partially amorphized polyester up to monomers and/or oligomer
Data Source
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Figure 3~4
AI summary
The present invention relates to processes for degrading plastic products and the uses thereof. The processes of the invention particularly comprise a step of amorphizing a plastic product prior to a step of depolymerization. The processes of the invention are particularly useful for degrading a plastic product comprising polyethylene terephthalate and/or polylactic acid. The invention also relates to a method of producing monomers and/or oligomers from a plastic product comprising at least one polyester, particularly polyethylene terephthalate and/or polylactic acid, comprising submitting the plastic product both to an amorphization step and to a depolymerization step.