A Universal Strategy to Enhance the Compatibility between PE and Fillers for Functional PE-Based Composites/Foams Fabrication

Functional polyethylene (PE)-based composites/foams with well-mixed fillers are attracting wide attention. However, the poor compatibility between PE and most fillers usually leads to filler agglomeration and foam failure. Herein, different from the usually used filler surface modification strategy, which is of high cost and cumbersome, we report a cost-effective, simple, and general strategy to enhance the compatibility between the PE matrix and fillers by blending and cross-linking ethylene–vinyl acetate copolymer (EVA) and maleic anhydride-grafted PE (MAH- g -PE) with PE. The increased functional groups in the matrix macromolecular chains promote the interaction with fillers, even with limited groups such as carbon fibers. The strategy also enhances the overall disorder of the matrix, resulting in decreased crystallinity and enhanced foaming ability. To demonstrate the concept, we prepared the electromagnetic interference (EMI) shielding foam by incorporating carbon black, carbon fiber, and Fe 3 O 4 in tunable amounts, which shows a high performance of 82.54 dB/(g/cm 3 ), comparable with the best reported results in filler–matrix systems. Moreover, this strategy can be used for high-performance flame-retardant foam fabrication and the integrated molding of multifunctional PE foams with multilayer structures by hot-pressing, cross-linking, and chemical foaming. This work provides a practical strategy for functional PE-based composites and foams.