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The rapid advancement of digitization and informatization has highlighted the significance of polymer-based electromagnetic interference (EMI) shielding composites. However, there has been a notable scarcity of efforts to enhance EMI shielding performance and mechanical properties in the backdrop of conductive polymer composites (CPCs). Herein, we present a novel approach utilizing bio-inspired polydopamine (PDA) chemically modified hollow glass microspheres (HGM), referred to as PDA@HGM, in conjunction with carbon nanostructures (CNS), to fabricate functional ultrahigh molecular weight polyethylene (UHMWPE) composites. These composites are synthesized using a mechanical mixing and hot-pressing method. Experimental outcomes provide insights into the influence rules of PDA@HGM incorporation on mechanical properties, electrical conductivity and EMI shielding performance of composites. It is determined that the PDA@HGM inclusion is observed to enhance EMI shielding performance of the composites by decreasing reflection and increasing absorption loss. Profited from the biomimetic interfacial reinforcement provided by the PDA, the total EMI shielding effectiveness (EMI SE) of PDA@HGM5 composite can be increased by 27 % with the highest value of 49.8 dB (12.4 GHz). Moreover, this obtained composite demonstrates an acceptable tensile strength, which can reach up to 32.31 MPa and outperforms to other unmodified HGM composites. This investigation further incorporates a comprehensive analysis, encompassing XPS, FT-IR, TGA, EDS, and FE-SEM, to systematically reveal the underlying mechanisms of HGM and PDA@HGM incorporation on EMI SE. Overall, these enhanced PDA@HGM composites demonstrate significant promise for the development of the high-performance lightweight CPCs.

To address the practical application challenges of conductive polymer composites (CPCs) in portable electronics equipment, such as their low thermal conductivity (TC) and poor electromagnetic interference (EMI) shielding effectiveness (EMI SE), it is crucial to improve their TC, electrical conductivity(σ), and EMI SE of CPCs. In this work, we present a conducting composite made of ultrahigh molecular weight polyethylene (UHMWPE) and carbon nanostructures (CNS) with a unique segregated structure. This structure is achieved through a simple high-speed mechanical mixing and compression molding process. Microscopy characteristics demonstrated that both the matrix and segregated conductive network were in-situ oriented along the compress direction of UHMWPE granules under the static hot-pressing field. CNS are compacted together at the interface between UHMWPE granules to form an oriented and interconnected conductive pathways at low CNS loading levels. The resultant UHMWPE/CNS composites with 10 wt% CNS content exhibits excellent EMI shielding performance, with EMI SE of 60.7 dB (at X-band), high conductivity of 2.42 S/cm, and acceptable thermal conductivity of 0.7217 (W/m K). High EMI shielding performance and absorption dominant mechanism are beneficial from the unique segregated structure, and individual CNS coated UHMWPE granule are similar to an electromagnetic cage. Additionally, the ultimate tensile strength of the composite remains high at 37.6 MPa even at 10.0 wt% CNS loading, and it shows effective thermal stability. These properties are attributed to the strong interfacial bonding between CNS and UHMWPE. These materials have potential applications in efficient thermal management and EMI shielding for high-performance intelligent electrical devices.

Good interfacial adhesion is one of the key factors to ensure the excellent performance of composite materials. However, the interfacial effect of fiber-polymer composites remain incompletely understood. Herein, a self-designed mold was used to prepare UHMWPE (Ultra-high molecular weight polyethylene)-fiber/LDPE (Low density polyethylene)-matrix (LU) and PET (polyethylene terephthalate)-fiber/LDPE-matrix composite materials (LP). The interfacial bonding effect was explored by the interfacial shear strength (IFSS), and the interfacial structure and failure mechanism during the fiber pull-out process were analyzed by the combination of experiment and finite element simulation. The results show that the IFSS of LU (3.59 MPa) is 3 times greater than that of LP (1.18 MPa), giving rise to a higher tensile strength. Moreover, Raman mapping and DSC results suggest that UHMWPE-fiber act as nucleation sites to improve the orientation and crystallization of LDPE molecular chains, generating an obvious interfacial transition zone between UHMWPE-fiber and LDPE, while no obvious interfacial transition zone is found between PET-fiber and LDPE. These findings will be expected to give some guidelines for the design and manufacturing high-performance fiber-polymer composites.