Effect Of Boron Nitride Nanosheets Research Articles

Mechanical and thermal performances of styrene butadiene rubber nanocomposites with boron nitride nanosheets, carbon nanotubes, and the hybrid filler system

AbstractPreparation of rubber nanocomposites using two or more nanofillers with different geometries is a new and promising approach. In this work, the effects of boron nitride nanosheets (BNNS), carbon nanotubes (CNT) and their hybrid (BNNS‐CNT) on the performances of styrene butadiene rubber (SBR) nanocomposites are systematically studied. The mechanical properties of the nanocomposites are significantly enhanced by the nanofillers. The tensile strength of unfilled SBR is only 1.30 ± 0.18 MPa, which increases to 1.72 ± 0.24 MPa (BNNS), 4.09 ± 0.35 MPa (CNT), and 3.37 ± 0.29 MPa (BNNS‐CNT) at 4 phr, respectively. Similarly, the tear strength of unfilled SBR is 8.0 kN/m, which increases to 13.8 kN/m (BNNS), 16.1 kN/m (CNT) and 18.2 kN/m (BNNS‐CNT) at 4 phr, respectively. Moreover, the thermal behavior of the nanocomposites are analyzed. Compared with single nanofiller BNNS or CNT, BNNS‐CNT hybrid nanofiller not only effectively improves the mechanical properties of nanocomposites, but also imparts better thermal properties. It is proved that the thermal decomposition temperature of SBR/4phr BNNS‐CNT is increased by nearly 7°C compared with unfilled SBR.

The effect of boron nitride nanosheets on the mechanical and thermal properties of aluminum nitride ceramics

The boron nitride nanosheets (BNNSs)/aluminum nitride (AlN) composites were prepared by hot press sintering at 1600°C. The microstructure, mechanical properties, and thermal conductivity of the samples were measured, and the effect of adding BNNSs to AlN ceramics on the properties was studied. It is found that the addition of BNNSs can effectively improve the mechanical properties of AlN. When the additional amount is 1 wt%, the bending strength of the sample reaches the maximum value of 456.6 MPa, which is 23.1% higher than that of the AlN sample without BNNSs. The fracture toughness of the sample is 4.47 MPa m1/2, a 68.7% improvement over the sample without BNNSs. The composites obtained in the experiment have brilliant mechanical properties.

Thin-film composite polyamide membrane modified by embedding functionalized boron nitride nanosheets for reverse osmosis

Modifying polyamide membranes with nanomaterials has proven effective for enhancing water flux and salt rejection and membrane resistance against fouling and chlorine. In this study, we prepared a novel thin-film nanocomposite reverse osmosis membrane by embedding functionalized boron nitride nanosheets (FBNS) into the polyamide layer via in situ interfacial polymerization process. As a result of the incorporation of FBNS, the expansion of homogeneous leaf-like structure of the polyamide layer, as indicated by the increased surface roughness as well as the thinner and more hydrophilic active layer, enhances the water permeance of membrane by 25% to 4.0 LMH/bar while maintaining a high salt rejection of 96.4%. The FBNS incorporated nanocomposite membranes also demonstrate improved chlorine resistance and performance stability under various stress test conditions when comparing to the pristine membrane. The humic acid fouling test indicates that the modified membrane has a flux recovery of over 96% after one cleaning cycle. This work provides new insights into the effect of boron nitride nanosheets on membrane network structures and separation performance and provides a scalable membrane improvement strategy based on emerging 2D nanosheets.

DC breakdown characteristics of XLPE/BNNS nanocomposites considering BN nanosheet concentration, space charge and temperature

Breakdown failure in insulation material is one of the key problems that threaten the safe operation of high-voltage direct current cable. In this work, the effect of boron nitride nanosheets (BNNSs) concentration, space charge and temperature on DC breakdown strength have been explored. Cross-linked polyethylene (XLPE)/BNNS nanocomposites were prepared by the melt blending method, and the basic characteristics of nanoparticles and composite were characterised. The experimental results indicate that DC breakdown strength of nanocomposite can be effectively improved when a small amount of BN nanosheet is doped into the matrix. The breakdown strength of the sample reaches the maximum value of 407.52 kV/mm when BNNS content is 0.5 wt%, which is about 33% higher than that of pure XLPE. Further, the effect of space charge on the breakdown of nanocomposites has been studied by pre-injecting charges. For the samples with different BNNS contents, all the breakdown strength present ascending trend when the polarity of the applied voltage is the same as that of the pre-injected charges. Besides, it can be found that the breakdown strength of the XLPE/BNNSs composite decreases significantly at 50°C, which is due to more charge accumulation at 50°C. It reaches 2.06 × 10 −8 C which increases by about 2.2 times than the room temperature.

Effect of Boron Nitride Nanosheets on Properties of a Commercial Epoxy Molding Compound Used in Fan-Out Wafer-Level Packaging

In this article, the effect of incorporating boron nitride nanosheets (represented as BNNSs in this article) in a commercial epoxy molding compound (EMC) that has been used in the fan-out wafer-level packaging (FOWLP) is investigated. The BNNSs were produced by exfoliating hexagonal boron nitride (h-BN) in water and were incorporated in EMC without any surface modification. BNNS-reinforced EMCs were prepared by adding various concentrations of BNNSs in the pristine EMC, followed by thermal curing. The characterization of nanocomposite samples implies that the epoxy-hardener reaction is not significantly affected by the presence of BNNSs. Surprisingly, EMCs containing low concentrations of BNNSs showed better thermal stability and thermomechanical properties when compared to the pristine EMC. Meanwhile, a sample with the highest concentration of BNNSs performed poorly, which could be due to the BNNS agglomeration and filler/polymer phase separation. This method is a simple and inexpensive way to alter the mechanical properties of commercial EMCs. The tunability of material properties is foreseen to broaden the materials of choice for FOWLP, support product customization, and tackle the warpage issue in FOWLP from the material engineering perspective.

Effect of BN nanosheet concentration on space charge characteristics in XLPE/BNNS nanocomposites

Space charge accumulation in insulation material is one of the key factors that threaten the safe operation of high voltage direct current (HVDC) cable. Nanocomposites have been considered as the potential material to solve the problem of charge accumulation in HVDC cable. In the work, the effect of boron nitride nanosheets (BNNSs) concentration on space charge accumulation characteristics in XLPE/BNNS nanocomposite have been explored. The experimental results indicate that space charge in nanocomposite can be effectively suppressed when a small amount of BN nanosheet (<0.5 wt%) is doped into the matrix. It is mainly due to the introduction of deep traps at the interface between electrode and nanocomposite, and the ‘charge barrier effect’ has been formed to inhibit charge injection. The trap level of nanocomposite is 0.95 eV and the trap number is 2.43 × 1020 m−3 for the concentration of 0.1 wt%. While, the charge inhibition effect in the nanocomposite becomes weaken with the increase of the BNNS concentration. PEA experimental results show that the accumulated charges increase when the concentration is 1 wt%, the charge amount in the composite reaches 1.08 × 10−5 C, and the local electric field distortion rate is 9.5%. For high concentration (>2 wt%∼3 wt%), the calculated results indicate that more relatively shallow traps are introduced in the composite, resulting in few accumulated charges. The trap level is 0.62 eV and the trapped charge density is 5.76 × 1020 m−3 at 5 wt%, which will enhance the charge hopping probability between the adjacent trap centers.

Synergistic effect of BN and graphene nanosheets in 3D framework on the enhancement of thermal conductive properties of polymeric composites

In this work, we reported a synergistic effect of boron nitride nanosheets (BNNSs) with graphene in the 3D BNNSs/graphene framework (BGF) on the enhancement of thermal conductive properties of polyamide-6 (PA6) composites. The 3D BGF was self-assembled by embedding BNNSs into 3D graphene framework (GF). And the PA6 composites were obtained by in-situ polymerization of PA6 chains in the pores of the 3D framework. The thermal conductivity (TC) of PA6 composites with BGF (1.6 wt% BNNS/6.8 wt% graphene) was improved to 0.891 W·m−1·K−1. This value indicated that additional introduction of 1.6 wt% BNNSs could increase the TC up to 87.6% and 350% compared with the composites containing 6.8 wt% 3D GF (0.475 W·m−1·K−1) and neat PA6 (0.196 W·m−1·K−1), respectively. The high efficiency of BNNSs on the TC enhancement could be attributed to the factors including the unobstructed 3D thermal conductive paths constructed by BNNSs, and the morphology-promoted synergistic effect between BNNSs and graphene nanosheets.

Largely enhanced dielectric properties of carbon nanotubes/polyvinylidene fluoride binary nanocomposites by loading a few boron nitride nanosheets

The ternary nanocomposites of boron nitride nanosheets (BNNSs)/carbon nanotubes (CNTs)/polyvinylidene fluoride (PVDF) are fabricated via a combination of solution casting and extrusion-injection processes. The effects of BNNSs on the electrical conductivity, dielectric behavior, and microstructure changes of CNTs/PVDF binary nanocomposites are systematically investigated. A low percolation value (fc) for the CNTs/PVDF binary system is obtained due to the integration of solution and melting blending procedures. Two kinds of CNTs/PVDF binary systems with various CNTs contents (fCNTs) as the matrix are discussed. The results reveal that compared with CNTs/PVDF binary systems at the same fCNTs, the ternary BNNSs/CNTs/PVDF nanocomposites exhibit largely enhanced dielectric properties due to the improvement of the CNTs dispersion state and the conductive network. The dielectric constant of CNTs/PVDF binary nanocomposite with 6 vol. % CNTs (fCNTs &amp;lt; fc) shows a 79.59% enhancement from 49 to 88 after the incorporation of 3 vol. % BNNSs. For the other CNTs/PVDF system with 8 vol. % CNTs (fCNTs &amp;gt; fc), it displays a 43.32% improvement from 1325 to 1899 after the addition of 3 vol. % BNNSs. The presence of BNNSs facilitates the formation of the denser conductive network. Meanwhile, the ternary BNNSs/CNTs/PVDF systems exhibit a low dielectric loss. The adjustable dielectric properties could be obtained by employing the ternary systems due to the microstructure changes of nanocomposites.

Akermanite scaffolds reinforced with boron nitride nanosheets in bone tissue engineering.

Akermanite (AKM) is considered to be a promising bioactive material for bone tissue engineering due to the moderate biodegradability and excellent biocompatibility. However, the major disadvantage of AKM is the relatively inadequate fracture toughness, which hinders the further applications. In the study, boron nitride nanosheets (BNNSs) reinforced AKM scaffolds are fabricated by selective laser sintering. The effects of BNNSs on the mechanical properties and microstructure are investigated. The results show that the compressive strength and fracture toughness increase significantly with BNNSs increasing from 0.5 to 1.0 wt%. The remarkable improvement is ascribed to pull out and grain wrapping of BNNSs with AKM matrix. While, overlapping sheets is observed when more BNNSs are added, which results in the decline of mechanical properties. In addition, it is found that the composite scaffolds possess good apatite-formation ability when soaking in simulated body fluids, which have been confirmed by energy dispersed spectroscopy and flourier transform infrared spectroscopy. Moreover, MG63 osteoblast-like cells and human bone marrow stromal cells are seeded on the scaffolds. Scanning electron microscopy analysis confirms that both cells adhere and proliferate well, indicating favorable cytocompatibility. All the facts demonstrate the AKM scaffolds reinforced by BNNSs have potential applications for tissue engineering.