Rapidly Self-Healable and Melt-Extrudable Polyethylene Reprocessable Network Enabled with Dialkylamino Disulfide...

Area of Science:

• Polymer Chemistry
• Materials Science
• Sustainable Polymers

Background:

• Conventional polymers often lack efficient reprocessing and self-healing capabilities.
• Developing adaptable polymer networks is crucial for sustainable materials development.
• Catalyst-free methods offer greener alternatives for polymer modification.

Purpose of the Study:

• To synthesize and characterize polyethylene covalent adaptable networks (PE CANs) from low-density polyethylene (LDPE).
• To investigate the impact of crosslinker structure (disulfide vs. oligosulfide bridges) on PE CAN properties.
• To evaluate the reprocessing, melt-extrudability, and self-healing performance of the synthesized PE CANs.

Main Methods:

• Catalyst-free, radical-based reactive processing of LDPE with BiTEMPS methacrylate (BTMA) crosslinkers.
• Synthesis of two types of PE CANs: S₂ PE CAN (disulfide bridges) and S<0xE2><0x82><0x99> PE CAN (oligosulfide bridges).
• Characterization of crosslink density, stress relaxation, reprocessing time, melt-extrudability, and self-healing efficiency.

Main Results:

• Both S₂ PE CAN and S<0xE2><0x82><0x99> PE CAN exhibited identical crosslink densities.
• S₂ PE CAN showed significantly faster stress relaxation and shorter compression-molding reprocessing times (5 min vs. 30 min).
• Both PE CANs were melt-extrudable with full crosslink density recovery and demonstrated self-healing properties.

Conclusions:

• The structure of the disulfide crosslinker critically influences the dynamic properties and reprocessing efficiency of PE CANs.
• PE CANs offer a promising platform for creating recyclable and self-healing polyethylene materials.
• Catalyst-free synthesis provides a viable route to advanced polymer networks with tunable properties.