Triboelectric polymer with high charge density is the foundation to promote the wide range of applications of triboelectric nanogenerators. This work develops a method to produce triboelectric polymer based on repeated rheological forging. The fluorinated ethylene propylene film fabricated by repeated forging method not only has excellent mechanical properties and good transmittance, but also can maintain an ultrahigh tribo-charge density. Based on the film with a thickness of 30 μm, the output charge density from contact-separation nanogenerator reaches 352 μC·m−2. Then, the same film is applied for the nanogenerator with air-breakdown mode and a charge density of 510 μC·m−2 is further achieved. The repeated forging method can effectively regulate the composition of surface functional groups, the crystallinity, and the dielectric constants of the fluorinated ethylene propylene, leading to the superior capability of triboelectrification. Finally, we summarize the key parameters for elevating the electrification performance on the basis of molecular structure and related fabrication crafts, which can guide the further development of triboelectric polymers.
Cr/W multilayer nanocomposites were presented in the paper as potential candidate materials for the plasma facing components in fusion reactors. We used neutron reflectometry to measure the depth profile of helium in the multienergy He ions irradiated [Cr/W (50 nm)]3 multilayers. Results showed that He-rich layers with low neutron scattering potential energy form at the Cr/W interfaces, which is in great agreement with previous modeling results of other multilayers. This phenomenon provided a strong evidence for the He trapping effects of Cr/W interfaces and implied the possibility of using the Cr/W multilayer nanocomposites as great He-tolerant plasma facing materials.
Novel, flexible, lead-free X-ray-shielding composites were prepared with a high-functional methyl vinyl silicone rubber (VMQ) matrix with W and Bi 2 O 3 as filler materials. To verify the advanced properties of the lead-free material, composites with the same mass fraction of PbO were compared. With the X-ray energy ranging from 48 to 185 keV, the W/Bi 2 O 3 /VMQ composites exhibited higher X-ray-shielding properties. As the filler volume fraction decreased, the tensile strength, elongation, tear strength, and flexibility of the W/Bi 2 O 3 /VMQ composites increased. The Shore hardness of the W/Bi 2 O 3 /VMQ composites had a maximum value of 46.6 HA and was still very flexible. With decreasing filler volume fraction, the water-vapor transmission performances of the W/ Bi 2 O 3 /VMQ composites increased, and the W/Bi 2 O 3 /VMQ composites also showed better water-vapor permeability. The heat-transfer properties of the W/Bi 2 O 3 /VMQ composites increased with increasing W content, and when the W content exceeded 70 wt %, the thermal conductivity of the W/Bi 2 O 3 /VMQ material was about 70.45% higher than that of the PbO/VMQ composite. V C 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43012.
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