Catalytic High-Speed Reactive Extrusion for Polyethylene Mechanochemical Upcycling.

Area of Science:

• Polymer Chemistry
• Materials Science
• Chemical Engineering

Background:

• Polyethylene (PE) recycling faces challenges in efficiently breaking down polymer chains.
• Developing sustainable and energy-efficient recycling methods is crucial for polyolefin waste management.

Purpose of the Study:

• To explore a mechanochemical strategy for PE recycling using ultrahigh-speed twin-screw extrusion (TSE).
• To investigate the synergistic effects of high shear rates and catalyst incorporation on PE structural transformations.
• To establish TSE as a process intensification approach for PE depolymerization.

Main Methods:

• Utilized ultrahigh-speed twin-screw extrusion (TSE) to apply specific mechanical energy (SME).
• Investigated linear and branched PE, with and without additives.
• Characterized structural, molecular, and rheological changes using FTIR, GPC, and rheology.
• Analyzed thermal properties using Thermogravimetric Analysis (TGA).

Main Results:

• Catalyst incorporation enhanced PE chain scission, producing low molecular weight byproducts.
• TSE with catalysts significantly reduced PE decomposition temperature.
• Mechanical energy input improved polymer-catalyst contact and reduced activation barriers.

Conclusions:

• TSE is an effective process intensification approach for controlling PE depolymerization.
• This mechanochemical strategy can serve as a preconditioning step for chemical recycling.
• The approach offers a pathway to lower thermal energy requirements for recycling, promoting sustainable polyolefin waste management.