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

Enhancing the insulating properties of polypropylene by means of modification is essential for the application of polypropylene materials. Herein, we utilized an aqueous-phase suspension crosslinking method to form slight-crosslinked structures within the amorphous region of polypropylene, achieved by regulating the DVB content crosslinked onto the polypropylene matrix. The breakdown strength of PP-c-DVB at room temperature reached 533.45 kV/mm, marking a remarkable 66% increase compared to pure PP (320.53 kV/mm). Both experimental results and DFT simulation calculation data confirm that the introduced DVB act as deep traps, restricting carrier transport and consequently enhancing the breakdown strength of polypropylene. Simultaneously, the slightly cross-linked structure of PP retains its excellent thermoplastic recyclability property even after undergoing three-times hot pressing process. This work provides a novel strategy to improve the insulation property of polypropylene-based material.