Plasma Surface Amorphization of PET for Enzymatic Depolymerization

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Solution Overview

Problem

Existing methods for recycling polyethylene terephthalate (PET) are inefficient, particularly in mechanical recycling due to contaminants and loss of molecular mass, and chemical recycling methods are costly and environmentally harsh, while enzymatic depolymerization requires PET to be weakly crystalline, which is challenging for contaminated PET components.

Innovation Solution

A method involving a plasma treatment with controlled atmospheric pressure and specific power conditions to amorphize PET surfaces, followed by enzymatic depolymerization, ensuring effective depolymerization without structural damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If mechanical recycling is used to create new PET objects from PET chips, then recycling efficiency is improved, but mechanical properties deteriorate due to contaminants and loss of molecular mass

Engineering Contradiction:
Improverecycling efficiencyVSAvoidmechanical properties
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The invention extracts and removes contaminants from PET components through the depolymerization process, separating the polymer chains into monomers that can be purified and repolymerized, thereby removing the harmful contaminants that degrade mechanical properties in mechanical recycling

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the chemical state of PET from polymer to monomer through depolymerization, then repolymerizes it to restore molecular mass and mechanical properties, transforming the material at the molecular level rather than just physically processing it

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If solvent-based chemical recycling is used to return PET to monomers, then material purity is improved, but environmental impact and cost increase due to harsh operating conditions

Engineering Contradiction:
Improvematerial purityVSAvoidenvironmental impact
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The invention changes the operating parameters from harsh solvent-based conditions to mild aqueous conditions with enzymes, achieving depolymerization at lower temperatures and pressures while maintaining material purity through biological catalysis rather than chemical solvents

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces mechanical/chemical force-based depolymerization with enzyme-catalyzed depolymerization, using biological catalysts to break down PET at mild conditions, thereby eliminating the need for harsh solvents and extreme operating conditions

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Object-affected harmful factors

If enzymatic depolymerization is used to depolymerize PET under mild conditions, then environmental impact is reduced, but effectiveness decreases when PET is highly crystalline

Engineering Contradiction:
Improveenvironmental impactVSAvoiddepolymerization effectiveness
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The invention performs a preliminary amorphization treatment on highly crystalline PET components before enzymatic depolymerization, transforming the crystalline structure into an amorphous state that is more accessible to enzymes, thereby enabling effective depolymerization of previously resistant materials

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention introduces an intermediary amorphization step that modifies the physical structure of crystalline PET to make it susceptible to enzymatic attack, acting as a bridge between the resistant crystalline state and the enzyme-accessible amorphous state

Inventive Principle:
Principle #24Intermediary (Mediator)

4Productivity

If twin-screw extruder is used for amorphization of PET, then amorphization efficiency is improved, but equipment cost and suitability for contaminated PET worsen

Engineering Contradiction:
Improveamorphization efficiencyVSAvoidequipment cost
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention replaces the mechanical extrusion system with a plasma treatment system for amorphization, using plasma energy to directly transform the crystalline structure without mechanical processing, thereby avoiding the need for expensive extruder equipment and its associated contamination issues

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 method achieves significant reduction in PET crystallinity to enable efficient enzymatic depolymerization, producing high-quality monomers with minimal environmental impact and equipment costs.

Implementation Method 1

the surface of the PET element is brought into contact with a plasma

Methodology Applied
Scientific EffectPlasma: Plasma

Implementation Method 2

an amorphization step in which the surface of the PET element is brought into contact with a plasma

Methodology Applied
Scientific EffectAmorphization:

Implementation Method 3

enzymatic depolymerization step

Methodology Applied
Scientific EffectEnzymatic depolymerization: Enzyme

Implementation Method 4

return the material to its monomers (terephthalic acid, ethylene glycol)

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Data Source

PatentEP4547743B1Process for the preparation of an element comprising polyethylene terephthalate for depolymerization
Publication Date: 2026.03.11 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)
  • EP4547743B1 patent drawingFigure 1~2

AI summary

The invention relates to a process for preparing a polyethylene terephthalate (PET) element, comprising at least one amorphization step in which the surface of the PET element is brought in contact with a plasma.