Due to the increasing pressure of environmental protection and the depletion of oil resources, Eucommia ulmoides gum (EUG) as a natural renewable and degradable biopolymer has attracted more and more attention. In this work, multilayer carbon nanotube film (CNF)/EUG composite films were fabricated through the infiltration and hot-pressing process. By taking advantage of the elasticity of EUG and the specific strength of CNF, composite films exhibited much more improved mechanical strength (maximum tensile stress up to 108.4 MPa) compared with pristine EUG and CNF alone. In addition, composite films prepared with five CNF layers and five infiltration cycles of EUG solution with a thickness of 181 μm can achieve the highest total shielding effectiveness value of 88 dB in 15.6 GHz. Moreover, the folded composite film can recover quickly to the fixed permanent shape when exposed to infrared light, demonstrating fascinating infrared-triggered shape memory behavior. This work provides a facile and general method to fabricate CNF/EUG composite films and is beneficial for pushing forward the practical application of EUG materials.
Yan Wang,Jinhui Liu,Lin Xia,Mei Shen,Liping Wei,Zhenxiang Xin,Jinkuk Kim
Novel, fully biobased shape memory thermoplastic vulcanizates (TPVs) were prepared using two sustainable biopolymers, poly(lactic acid) (PLA), and modified naturalEucommia ulmoidesgum (EUG-g-GMA), via a dynamic vulcanization technique. Simultaneously, in situ compatibilization was achieved in the TPVs to improve interfacial adhesion and the crosslinked modifiedEucommia ulmoidesgum (EUG) was in “netlike” continuous state in the PLA matrix to form “sea-sea” phase structure. The promoted interface and co-continuous structure played critical roles in enhancing shape memory capacity and toughness of the TPVs. The TPV with 40 wt % modified EUG displayed the highest toughness with an impact strength of 54.8 kJ/m2and the most excellent shape memory performances with a shape fixity ratio (Rf) of 99.83% and a shape recovery ratio (Rr) of 93.74%. The prepared shape memory TPVs would open up great potential applications in biobased shape memory materials for smart medical devices.
Conventional electromagnetic interference (EMI) shielding materials remain heavily mold-dependent. This constrains design freedom, limiting structural customizability and manufacturing flexibility for modern electronics. This study successfully fabricated multifunctional polylactic acid/ Eucommia ulmoides gum/silver-coated carbon fiber (PLA/EUG/CF@Ag) composites via fused deposition modeling (FDM) three-dimensional (3D) printing. Uniform dispersion and aligned orientation of CF@Ag within the polymer matrix were achieved through ball milling and twin-screw extrusion, constructing efficient conductive and thermal networks. A gradient porous structure based on triply periodic minimal surfaces (TPMS) was designed and printed, which significantly enhanced electromagnetic wave absorption and heat dissipation. With a CF@Ag loading of 25 wt%, the composite exhibited a total electromagnetic interference shielding effectiveness (EMI SE) of 36 dB in the X-band (8.2–12.4 GHz). Compared to solid board structures, the gradient structure improved heat dissipation efficiency by 230% while simultaneously reducing the electromagnetic wave reflection coefficient from 0.90 to 0.68, demonstrating superior reflection-reduced shielding. This work provides a novel strategy for developing lightweight, customizable, and multifunctional electromagnetic interference shielding materials with promising applications in electronic packaging and aerospace.
危险品化学品经营许可证（带存储）