Slightly Crosslinked Structure Highly Improves Insulation Properties of Polypropylene with Good Recyclable...

Area of Science:

• Materials Science
• Polymer Chemistry
• Electrical Insulation

Background:

• Polypropylene (PP) materials require enhanced insulating properties for broader applications.
• Modification of PP is crucial for improving its dielectric performance.

Purpose of the Study:

• To enhance the insulating properties of polypropylene through a novel crosslinking method.
• To investigate the impact of divinylbenzene (DVB) crosslinking on PP's breakdown strength and recyclability.

Main Methods:

• Utilized an aqueous-phase suspension crosslinking method to introduce slight-crosslinked structures in PP.
• Regulated DVB content to control the crosslinking density within the amorphous region of the polypropylene matrix.
• Evaluated breakdown strength at room temperature and assessed thermoplastic recyclability after hot pressing.

Main Results:

• The breakdown strength of crosslinked PP (PP-c-DVB) reached 533.45 kV/mm, a 66% increase over pure PP (320.53 kV/mm).
• Density Functional Theory (DFT) simulations and experimental data confirmed DVB acts as deep traps, restricting carrier transport and enhancing breakdown strength.
• The slightly cross-linked PP maintained excellent thermoplastic recyclability even after three hot pressing cycles.

Conclusions:

• Aqueous-phase suspension crosslinking with DVB is an effective strategy to significantly improve polypropylene's electrical insulation properties.
• The DVB crosslinking mechanism enhances breakdown strength by trapping charge carriers without compromising thermoplastic recyclability.
• This research offers a promising pathway for developing high-performance, recyclable polypropylene-based insulating materials.