Polymer blend templated hierarchical porous composites with segregated structure and enhanced electromagnetic interference shielding performance

Abstract

Conductive network built by less conductive filler is vital for high‐performance conductive polymer composites. Herein, porous ultrahigh molecular weight polyethylene (UHMWPE)/poly(vinylidene fluoride) (PVDF) blends filled with multi‐walled carbon nanotubes (MWCNT) were fabricated, where poly(lactic acid) (PLA) and polymethyl methacrylate (PMMA) were served as sacrificial template. An interconnecting conductive network is formed based on the UHMWPE segregated structure and PVDF co‐continuous structure in porous UHMWPE/PVDF/MWCNT (UFC) composites. The UFC composites demonstrate a low electrical percolation threshold (0.25 wt%) due to the segregated/co‐continuous structure. Porous UFCs exhibit higher electromagnetic interference shielding effectiveness (EMI SE) than their compact counterparts. The blend‐templated porous structure enhances the EMI SE of composites because a well‐dispersed and densely packed MWCNT network is formed around the polymer particles, facilitating the multiple reflections of electromagnetic waves inside the composites. This effort provides a facile way for preparing high‐performance shielding materials by controlling the hierarchical structure and conductive filler distribution.Highlights Hierarchical porous structure was constructed by blend sacrificial templating method. Carbon fillers are exclusively distributed at blend interface, forming the segregated structure. Porous composites exhibit better shielding performances than their solid counterparts.

Enhanced Interface Bonding of Segregated Conductive Elastomeric Foams by Dynamic Cross-Linking Reshuffling: Toward Highly Sensitive Piezoresistive Sensors

“…Through the rational design of processing parameters, the conductive fillers are selectively distributed in the polymer phase interfaces, i.e., the polymer is segregated by the conductive fillers into micronano phase domains. As a result, a complete spatial interconnection network is constructed with a low filler content, which significantly improves the electrical conductivity of the composites. , Coating the fillers onto the surface of polymer granules and the following hot-press molding is a common method to fabricate CPCs with segregated structures, in which the polymer matrix is limited to thermoplastics with high melt viscosity, , whereas the irreversible cross-linking networks of thermosets hinders the diffusion of molecular chains and makes it difficult to construct segregated structural composites. ,, For example, ultrahigh molecular weight polyethylene was reported to be a suitable matrix because high viscosity hinders the penetration of conductive fillers into the micronano phase domains, which is conducive to the formation of a segregated structure. − …”

Effect of interfacial morphology on electromagnetic shielding performance of poly (l‐lactide)/polydimethylsiloxane/multi‐walled carbon nanotube composites with honeycomb like conductive networks

“…The EMI shielding effectiveness (EMI SE) of CPCs is mainly determined by their composition and structures 24–26 . Currently, adjusting the structure of CPCs to achieve excellent EMI SE, which is regarded as the simplest and most effective method to fabricate high‐efficiency EMI shielding materials, has become a hot research topic 27–29 .…”