An overview of boron nitride based polymer nanocomposites (original) (raw)
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ACS Applied Nano Materials, 2019
A detailed study has been undertaken of the mechanisms of stress transfer in a nanocomposite consisting of hexagonal boron nitride (hBN) nanotubes (BNNTs) in a poly(vinyl alcohol) (PVA) matrix based upon the use of nonresonance Raman spectroscopy. The structure of the BNNTs was characterized by using transmission electron microscopy (TEM) where it was shown that the majority of the nanotubes had 2−5 walls with some having over 10 walls. The structure and mechanical properties of nanocomposites containing up to 1 wt % of both pristine and hydroxyl-functionalized nanotubes (OH-BNNTs) in PVA were investigated. The dispersion of the BNNTs in the nanocomposites was characterized by using a combination of transmission electron microscopy and Raman mapping. The mechanical properties of the nanocomposites were evaluated by tensile testing, and it was found that the Young's modulus, yield strength, and fracture stress all increased on the addition of the BNNTs. A further improvement in the mechanical properties was obtained for nanocomposites containing the OH-BNNTs. The variation of the Young's modulus of the nanocomposites with volume fraction of the BNNTs was evaluated by using the rule of mixtures, and it was shown that the effective Young's modulus (E eff) of the BNNTs approached 825 ± 100 GPa at low volume fractions. The value of E eff was found to decrease with increasing BNNT volume fraction as the result of nanotube bundling. By use of nondestructive Raman spectroscopy, stress transfer from the PVA matrix to the BNNTs was evaluated from stress-induced shifts of the hBN Raman G band, enabling the analysis of interfacial adhesion in the nanocomposites. Larger band shifts were obtained for the OH-BNNTs indicating a stronger interface between the BNNTs and the PVA matrix and a better dispersion. A value of 1.34 ± 0.72 was determined from the stress-induced Raman band shifts for the Gruneisen parameter of the BNNTs. In consideration of their efficient reinforcement of a polymer at very low additions and unique electrically insulating and thermally conductive properties, BNNTs are shown to have great potential to be used as nanofillers for composites in a number of applications.
Boron Nitride-Based Nanomaterials: Synthesis and Application in Rechargeable Batteries
Batteries
Conventional boron nitride material is a resistant refractory compound of boron and nitrogen with various crystalline forms. The hexagonal form, which corresponds to graphite, is used as a lubricant and an additive to cosmetic products because of its higher stability and softness. Recently, various nanostructured boron nitride materials, including nanosheets, nanotubes, nanoparticles, and nanocomposites with diverse new properties, have been achieved through the development of advanced synthesis techniques as well as a deeper understanding of the properties and related applications. As nanostructured boron nitride materials exhibit high chemical, thermal and mechanical stability, the incorporation of nanostructured boron nitride materials into the key components (electrolytes, separators, and electrodes) of electrochemical systems can alleviate various inherent problems. This review article systematically summarizes the integration of nanostructured boron nitride into electrolytes, ...
Journal of Materials Science, 2016
Functionalization of boron nitride nanosheets (BNNSs) has always been a challenge due to its chemical inertness and anti-oxidative properties. In a concentrated base environment, the B-N bonds on the surface of BNNSs were broken to produce a large number of B-OH and N-H functional groups. Afterwards, aniline carbocation produced by decomposition of the diazonium salt was utilized to achieve high grafting content of Ph-NH 2 groups onto the surface of BNNSs. Further, the amide reaction between amino and stearyl chloride verified the reactivity of Ph-NH 2 groups on the surface of BNNSs, with the result that BNNSs were abundantly decorated by aliphatic chains at 22.9 wt% grafting yield. The surface aliphatic chains of BNNSs strongly improved the interfacial adhesion between the High-density polyethylene (HDPE) matrix and the filler and provided an excellent dispersion of SC-BNNSs in the HDPE matrix. Therefore, HDPE/SC-BNNSs nanocomposites showed improved thermal stability, thermal conductivity, neutron shielding property and flexural modulus with no apparent reduction in tensile strength. When filler content exceeded 5 wt%, the HDPE/SC-BNNSs nanocomposites showed a higher thermal decomposition temperature than the composites with pristine BNNSs fillers. POLYM.
The controlled synthesis of boron nitride at the nanoscale with predefined and uniform nanostructures and architectures is in general a big challenge, and making full use of these materials in applications still requires great effort. In this article, recent progress on the synthesis of nanostructured and architectured boron nitride involving molecular and polymeric precursors which contain only boron, nitrogen and hydrogen are reviewed. The potential applications of these materials with controlled porosity and/or dimensions controlled at the nanoscale as zero, one, two and three dimensional materials are discussed. Finally, future prospects for boron nitride in terms of synthesis and applications are considered.
ACS applied materials & interfaces, 2016
This paper reports on the enhancement of the thermal transport properties of nanocomposite materials containing hexagonal boron nitride in poly (vinyl alcohol) through room-temperature atmospheric pressure direct-current microplasma processing. Results show that the microplasma treatment leads to exfoliation of the hexagonal boron nitride in isopropyl alcohol, reducing the number of stacks from >30 to a few or single layers. The thermal diffusivity of the resulting nanocomposites reaches 8.5 mm2 s-1, 50 times greater than blank poly (vinyl alcohol) and twice that of nanocomposites containing non-plasma treated boron nitride nanosheets. From TEM analysis, we observe much less aggregation of the nanosheets after plasma processing along with indications of an amorphous carbon interfacial layer which may contribute to stable dispersion of boron nitride nanosheets in the resulting plasma treated colloids.
Bulk quantity and physical properties of boron nitride nanocapsules with a narrow size distribution
Carbon, 2005
A new synthesis route for the formation of boron nitride (BN) nanocapsules by means of a substitution process using single wall carbon nanotubes as templates, with yields of >95% is presented. It is also shown that these BN nanocapsules can act as ideal reference samples for the determination of the relative sp 2 to sp 3 configuration in BN species, a value that is crucial for the physical properties of these nanostructures.
New synthetic route for nanocrystalline boron nitride powder
Materials Letters, 2011
Nanocrystalline hexagonal boron nitride powder (h-BN) was synthesized by sol-gel polycondensation of resorcinol and formaldehyde in the presence of boric acid followed by freeze drying. Pyrolysis and subsequent heat treatment of these cryogels resulted in formation of boron nitride powder. Characterization by nitrogen adsorption showed that precomposite cryogels and the BN powders were micro and mesoporous materials with high surface areas. Materials have been analyzed by means of X-ray diffraction, Raman scattering and electron microscopy methods.