Exploring a method to fabricate robust and stable 3D conductive networks in polymers matrix is still the challenge in the research and development of electromagnetic interference (EMI) shielding materials. Here, a feasible approach is provided to produce high‐performance, silicone‐doped MXene EMI shielding composites. The trace amount of hydroxyethyl cellulose is deliberately applied as gels to construct the MXene aerogels with a stable and highly conductive network by the freeze‐drying method. For more desirable mechanical and waterproof properties, the silicone resin is introduced into the MXene aerogels on purpose. The best silicone‐doped MXene EMI shielding composites display a superior electrical conductivity of 3166.4 S m−1, and EMI shield effectiveness of 74.5 dB at the X‐band (8.2–12.4 GHz). It is worth noting that the introduction of silicone resins sharply improves the hydrophobicity of EMI shielding materials to a range of water contact angle of about 151.5°–155.0°. This is a promising method to make MXene‐based EMI shielding composites with self‐cleaning function.
Green and environment-friendly
high-efficiency flame retardants
(FRs) are crucial to polymer FR modification. Here, a green FR 2-((bis(2-hydroxyethyl)amino)methyl)-5,5-dimethyl-1,3,2-dioxaphosphinane
2-oxide (HAMPP) was synthesized. The HAMPP was incorporated with a
cyclic phosphorus structure, which will readily carbonize to inhibit
or prevent further combustion. Moreover, the HAMPP contains dihydroxy
reactive groups that can be used as a monomer in the polymerization
reaction to obtain the main chain containing phosphorus polymer. Research
studies on FRs were based on flexible polyurethane foam (PU-HAMPPs).
The limiting oxygen index value of PU foam with 10% HAMPP could reach
23.7%, passing a UL-94 V-0 rating together. With the addition of HAMPP,
the peak heat release rate of PU foam decreased significantly, the
decomposition temperature increased, the heat release capacity reduced
by 31%, and the char yield increased by 42%. The chemical composition
and morphology of the char residual have been studied and analyzed
thoroughly. We find that HAMPP forms a molten viscous protective layer
uniformly on the material surface and releases some incombustible
gases. These indicated that the FR exploited both condensed-phase
and gas-phase flame retardancy mechanisms. Besides, the addition of
FRs improved the mechanical properties.
In this work, hexagonal boron nitride (h-BN) nanocrystals as functional additives in a phosphor-in-glass film are shown to substantially increase the luminous performance driven by a blue laser. Microstructural and spectroscopic studies reveal that h-BN particles distributed over the whole glass matrix build in situ a local heat conductive path which effectively accelerates heat dissipation and so greatly relieves the “thermal run-away effect”. The developed composite material with fine thermal manipulation may be a promising phosphor color converter for high-power-density laser-driven lighting.
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