Boron Nitride Nanoparticles Research Articles

Hydrothermal synthesis of chiral carbon dots.

Nanocolloidsthat are cumulatively referred to as nanocarbons, attracted significant attention during the last decade because of facile synthesis methods, water solubility, tunable photoluminescence, easy surface modification, and high biocompatibility. Among the latest development in this reserach area are chiral nanocarbons exemplified by chiral carbon dots (CDots). They are expected to have applications in sensing, catalysis, imaging, and nanomedicine. However, the current methods of CDots synthesis show often contradictory chemical/optical properties and structural information that required a systematic study with careful structural evaluation. Here, we investigate and optimize chiroptical activity and photoluminescence of L- and D-CDots obtained by hydrothermal carbonization of L- and D-cysteine, respectively. Nuclear magnetic resonance spectroscopy demonstrates that they are formed via gradual dehydrogenation and condensation reactions of the starting amino acid leading to particles with a wide spectrum of functional groups including aromatic cycles. We found that the chiroptical activity of CDots has an inverse correlation with the synthesis duration and temperature, whereas the photoluminescence intensity has a direct one, which is associated with degree of carbonization. Also, our studies show that the hydrothermal synthesis of cysteine in the presence of boric acid leads to the formation of CDots rather than boron nitride nanoparticles as was previously proposed in several reports. These results can be used to design chiral carbon-based nanoparticles with optimal chemical, chiroptical, and photoluminescent properties.

Synergistic effect of hybrid hydroxylated boron nitride and cellulose nanocrystals for enhancing the thermal, mechanical, and hydrophobic properties of composite film

AbstractHybrid composite films are largely preferred over neat films because of their superior thermal, mechanical, chemical, and hydrophobic properties. The hybrid composite film has a wide range of use, including space, defense, electronics, packaging, and engineering applications. Fabricating multifunctional hybrid composite films with biodegradable polymer and biodegradable filler such as cellulose nanocrystals has become popular in recent years as an alternative to conventional plastics. In this paper, hybrid hydroxylated boron nitride (BN) nanoparticles with CNC nano‐filer reinforced composite PVA films were fabricated. The obtained composite films were characterized for morphological, chemical, physical, thermal, and hydrophobic properties. The morphological analysis indicates that the hybrid nano‐filler was well dispersed in the poly(vinyl alcohol) (PVA) matrix. The reaction and hydrogen bond interactions between CNC and BN in composite films are confirmed by the Fourier transform infrared spectroscopy and x‐ray diffraction pattern. The contact angle method is used to confirm the enhancement of the hydrophobic property. The physical properties of the composite films and neat PVA film were analyzed by tensile test method using a universal testing machine. The thermal stability of the neat PVA film and the composite films were analyzed by the thermo‐gravimetric analysis method. The effect of hybridization of nanoparticles on the thermal, mechanical, and hydrophobic properties was studied. The hybrid composite film with enhanced properties allows it for multifunctional applications.

Thermally conductive and mechanically strengthened bio‐epoxy/boron nitride nanocomposites: The effects of particle size, shape, and combination

AbstractBio‐epoxy composites containing boron nitride (BN) particles with different size and shape (0D spherical micro‐ and nanoparticles, 1D nanotubes (T), and 2D nanosheets (S)) are prepared and revealed appropriate thermal conductivity, thermal stability, and mechanical properties. Systems containing one or two BN nanoparticles showed evenly dispersed structures because of applying high‐shear, ultrasonic, or combination of these methods. Microscopic analysis proved that high‐shear assisted ultrasonic technique ended up in an homogeneously dispersed BN nanoparticles in the epoxy matrix. The combination of platelet‐like and tubular nanoparticles synergistically enhanced both the thermal stability and thermal conductivity of epoxy. Differential scanning calorimetry (DSC) thermographs appeared a sharp peak demonstrating excessive thermal energy released because of network formation of BN conductive fillers. The bi‐oepoxy containing equal weight fractions of T and S (1:1 w/w ratio) showed the highest thermal conductivity and tensile strength values of 2.21 W/m.K and 80 MPa, respectively. In conclusion, properties of epoxy nanocomposites are affected by the filler network formation, such that conductive incorporation of 3 wt.% of BN platelet‐like and nanotubes increased thermal conductivity up to 1400% and mechanical properties up to 50% with respect to the neat epoxy.

Targeted photodynamic therapy of glioblastoma mediated by platelets with photo-controlled release property

Photodynamic therapy (PDT) has recently emerged as a promising, targeted treatment modality for glioblastoma (GBM) which is the most vicious type of brain tumor. Successful GBM-PDT hinges upon light activation of a photosensitizer accumulated in the tumor. However, inadequate tumor accumulation of photosensitizer severely limits the success of PDT of GBM. To tackle this difficulty, we herein propose a drug delivery strategy of “platelets with photo-controlled release property”. This strategy exploits platelets as carriers to deliver a photosensitizer which, in the current study, is a nano-composite (BNPD-Ce6) comprised of chlorine e6 (Ce6) loaded to boron nitride nanoparticles with a surface coating of polyglycerol and doxorubicin. To demonstrate the working mechanism and therapeutic advantage of this strategy, we loaded mouse platelets with BNPD-Ce6 to yield the nano-device BNPD-Ce6@Plt. In vitro experiments showed BNPD-Ce6@Plt to have a high loading capacity and efficiency. Laser irradiation (LI) at a wavelength of 808 nm induced ROS generation in BNPD-Ce6@Plt which displayed rapid activation, aggregation, and speedy discharge of BNPD-Ce6 into co-cultured GL261 mouse GBM cells which in turn, after LI, exhibited marked ROS generation, DNA damage, reduced viability, and cell death. In vivo animal experiments, mice that were intravenously injected with BNPD-Ce6@Plt exhibited rapid and extensive BNPD-Ce6 accumulation in both subcutaneous and intra-brain GL261 tumors shortly after LI of the tumors and the tumors displayed massive tissue necrosis after LI for a second time. Finally, a PDT regimen of two intravenous BNPD-Ce6@Plt injections each followed by multiple times of extracranial LI at the tumor site significantly inhibited the growth of intra-brain GL261 tumors and markedly increased the survival of the host animals. No apparent tissue damage was found in vital organs. Our findings make a compelling case for the notion that platelets are efficient carriers that can photo-controllably deliver nano-photosensitizers to achieve highly targeted and efficacious PDT of GBM. This work presents a novel approach to GBM-PDT with great translational potential.

Performance evaluation of thermally aged ATH and BN co‐doped silicone rubber nano‐micro composites for power cable applications

AbstractPower cables are intended to operate at high temperatures over a long period which may change the performance of silicone rubber insulation used in high voltage cable accessories. Therefore, in the current study, to enhance the properties of silicone rubber, alumina try‐hydrate (ATH) and boron nitride (BN) micro and nanoparticles were added to the silicone rubber matrix. The synthesized undoped silicone rubber, silicone rubber with 40 wt% micro ATH, 7 wt% nano BN, and 10 wt% micro ATH + 5 wt% nano BN composites were thermally aged for 600 h at 180ºC. The composite properties were analyzed through electrical, thermal, and physicochemical techniques. To assess the electrical characteristics, water droplet‐initiated corona discharge studies as per IEC 60112 were conducted and leakage current, corona inception voltage, and erosion resistance were evaluated. A deep learning technique also was employed for the prediction of erosion resistance of the samples. Further, to examine the surface texture and chemical changes on the surface of the material, 3‐D microscopy and Fourier transform infrared spectroscopy (FTIR) was adopted. Finally, thermal distribution analysis was performed for all the composites by infrared thermography. The results demonstrated the suitability of nano‐micro co‐doped composites over nanocomposites and micro composites for power cable applications.

Experimental and Theoretical Study of Sorption Capacity of Hexagonal Boron Nitride Nanoparticles: Implication for Wastewater Purification from Antibiotics.

The constant accumulation of antibiotics and their degradation products in wastewater as a result of human activity poses a serious threat to humanity and other living beings. To contribute to solving this important problem, hollow hexagonal boron nitride nanoparticles (BNNPs) with a spherical shape and smooth surface were synthesized, which were characterized as an efficient adsorbent for wastewater treatment from three types of antibiotics: ciprofloxacin (CIP), tetracycline (TC), and benzylpenicillin (BP). As follows from DFT calculations, the interaction of antibiotic molecules (AM) with the BN surface is neither purely physical nor purely chemical, and negative binding energy (BE) indicates that the adsorption process is spontaneous and endothermic. The calculated electron density redistributions at the AM/BN interfaces show that antibiotics interact with BN mainly through oxygen-containing groups. In addition, this interaction causes the BN surface to bend, which increases both the BE and the contact area. The removal efficiency of antibiotics (Re, %) depends on their initial concentration. At an initial concentration of 10 µg/mL, Re50 and Re100 were observed after 24 h and 14 days, respectively. With an increase in the initial concentration to 40 μg/mL, Re50 and Re100 were achieved after 5 and 28 days (with the exception of ciprofloxacin (~80% Re)). The maximum sorption capacity of BNNPs (qe) was determined to be 297.3 mg/g (TC), 254.8 mg/g (BP), and 238.2 mg/g (CIP), which is significantly superior to many other systems. Tetracycline is adsorbed much faster than the other two antibiotics, which is confirmed by both theoretical and experimental data. Based on the results of the DFT analysis, a simple and efficient sorbent regeneration strategy was proposed, which ensures complete removal of antibiotics after 14 (BP), 21 (TC), and 10 (CIP) days. Thus, the obtained results clearly show that BNNPs are promising sorbents for various classes of antibiotics, including aminoglycosides, tetracyclines, and β-lactams.

Low-energy repeated impact response of nanoparticle reinforced carbon fiber epoxy composite pipes

Fiber reinforced composite pipes, which are generally used to transport petroleum, natural gas, chemical liquids, and gases can be subjected to single or repeated low-energy impact loads under service conditions. Composites are materials that are highly sensitive to impact. For this reason, when they are exposed to low-energy impact, damages occur on the material that is difficult to prevent. The composite structure is reinforced by using nanoparticles in order to reduce these damages on the material and therefore increase the impact resistance of fiber reinforced composite pipes. In this study, filament wound carbon fiber epoxy composite pipes were reinforced with multi-walled carbon nanotubes (MWCNTs) and boron nitride nanoparticles (BNNPs). In order to examine the repeated impact response of the produced neat and reinforced pipes, repeated impact tests were carried out at different energy levels (10, 15 and 20 J). Damage mechanisms due to repeated impact were investigated. As a consequence of the experiments, it was concluded that the nanoparticle reinforcement increased the energy absorption capacity of the composite materials and significantly reduced the damage to the materials.

Electromagnetic Wave Absorbing, Thermal-Conductive Flexible Membrane with Shape-Modulated FeCo Nanobelts.

Electromagnetic wave (EMW)-absorbing materials, manufactured with composites of magnetic particles, are essential for maintaining a high complex permeability and modulated permittivity for impedance matching. However, commonly available EMW-absorbing materials are unsatisfactory owing to their low complex permeability in the high-frequency band. Herein, we report a thin, flexible EMW-absorbing membrane comprising shape-modulated FeCo nanobelts/boron nitride nanoparticles, which enables enhanced complex permeability in the S, C, and X bands (2-12 GHz). The boron nitride nanoparticles that are introduced to the FeCo nanobelts demonstrate control of the complex permittivity, leading to an effective impedance matching close to 1, consequently resulting in a high reflection loss value of -42.2 dB at 12.0 GHz with only 1.6 mm thickness. In addition, the incorporation of boron nitride nanoparticles improves the thermal conductivity for the heat dissipation of the absorbed electromagnetic wave energy. Overall, the comprehensive study of nanomaterial preparation and shape modulation technologies can lead to the fabrication of an excellent EMW-absorbing flexible composite membrane.

Photocontrol of Single-Photon Generation in Boron Nitride Nanoparticles: Implications for Quantum Photon Sources, Sub-Diffraction Nanoscopy, and Bioimaging

Photocontrol of Single-Photon Generation in Boron Nitride Nanoparticles: Implications for Quantum Photon Sources, Sub-Diffraction Nanoscopy, and Bioimaging

Ameliorative Effects by Hexagonal Boron Nitride Nanoparticles against Beta Amyloid Induced Neurotoxicity.

Alzheimer’s disease (AD) is considered as the most common neurodegenerative disease. Extracellular amyloid beta (Aβ) deposition is a hallmark of AD. The options based on degradation and clearance of Aβ are preferred as promising therapeutic strategies for AD. Interestingly, recent findings indicate that boron nanoparticles not only act as a carrier but also play key roles in mediating biological effects. In the present study, the aim was to investigate the effects of different concentrations (0–500 mg/L) of hexagonal boron nitride nanoparticles (hBN-NPs) against neurotoxicity by beta amyloid (Aβ1-42) in differentiated human SH-SY5Y neuroblastoma cell cultures for the first time. The synthesized hBN-NPs were characterized by X-ray diffraction (XRD) measurements, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Aβ1-42-induced neurotoxicity and therapeutic potential by hBN-NPs were assessed on differentiated SH-SY5Y cells using MTT and LDH release assays. Levels of total antioxidant capacity (TAC) and total oxidant status (TOS), expression levels of genes associated with AD and cellular morphologies were examined. The exposure to Aβ1-42 significantly decreased the rates of viable cells which was accompanied by elevated TOS level. Aβ1-42 induced both apoptotic and necrotic cell death. Aβ exposure led to significant increases in expression levels of APOE, BACE 1, EGFR, NCTSN and TNF-α genes and significant decreases in expression levels of ADAM 10, APH1A, BDNF, PSEN1 and PSENEN genes (p < 0.05). All the Aβ1-42-induced neurotoxic insults were inhibited by the applications with hBN-NPs. hBN-NPs also suppressed the remarkable elevation in the signal for Aβ following exposure to Aβ1-42 for 48 h. Our results indicated that hBN-NPs could significantly prevent the neurotoxic damages by Aβ. Thus, hBN-NPs could be a novel and promising anti-AD agent for effective drug development, bio-nano imaging or drug delivery strategies.

Effect of mixing procedure of oleic acid and BN nanoparticles as additives on lubricant performance of PAO8

Nanoparticles can be added as anti-friction and anti-wear additives to lubricating oil to achieve better lubrication performance. In this study, we demonstrate that the mixing procedure of BN nanoparticles and oleic acid (OA) influences the lubricant performance of PAO8. Lower friction and wear can be realized when OA and BN nanoparticles are mixed simultaneously in PAO8 than those with pre-mixed BN nanoparticles and OA. The tribological performance of the prepared lubricant was ascribed to the synergistic effect of the migration of well-dispersed BN nanoparticles and the adsorption of free OA on the metal surface. These results suggest that attention should be paid to the potential effect of the mixing procedure of additives, which might affect the performance of lubricants.

Boron Nitride Nanoparticles Loaded with a Boron-Based Hybrid as a Promising Drug Carrier System for Alzheimer's Disease Treatment.

The search for an innovative and effective drug delivery system that can carry and release targeted drugs with enhanced activity to treat Alzheimer’s disease has received much attention in the last decade. In this study, we first designed a boron-based drug delivery system for effective treatment of AD by integrating the folic acid (FA) functional group into hexagonal boron nitride (hBN) nanoparticles (NPs) through an esterification reaction. The hBN-FA drug carrier system was assembled with a new drug candidate and a novel boron-based hybrid containing an antioxidant as BLA, to constitute a self-assembled AD nano transport system. We performed molecular characterization analyses by using UV-vis spectroscopy, Fourier transform infrared spectrophotometer (FTIR), scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy (EDS) and Zeta potential investigations. Second, we tested the anti-Alzheimer properties of the carrier system on a differentiated neuroblastoma (SHSY5-Y) cell line, which was exposed to beta-amyloid (1–42) peptides to stimulate an experimental in vitro AD model. Next, we performed cytotoxicity analyses of synthesized molecules on the human dermal fibroblast cell line (HDFa) and the experimental AD model. Cytotoxicity analyses showed that even higher concentrations of the carrier system did not enhance the toxicological outcome in HDFa cells. Drug loading analyses reported that uncoated hBN nano conjugate could not load the BLA, whereas the memantine loading capacity of hBN was 84.3%. On the other hand, memantine and the BLA loading capacity of the hBN-FA construct was found to be 95% and 97.5%, respectively. Finally, we investigated the neuroprotective properties of the nano carrier systems in the experimental AD model. According to the results, 25 µg/mL concentrations of hBN-FA+memantine (94% cell viability) and hBN-FA+BLA (99% cell viability) showed ameliorative properties against beta-amyloid (1–42) peptide toxicity (50% cell viability). These results were generated through the use of flow cytometry, acetylcholinesterase (AChE) and antioxidant assays. In conclusion, the developed drug carrier system for AD treatment showed promising potential for further investigations and enlightened neuroprotective capabilities of boron molecules to treat AD and other neurodegenerative diseases. On the other hand, enzyme activity, systematic toxicity analyses, and animal studies should be performed to understand neuroprotective properties of the designed carrier system comprehensively.

Friction Properties of the Heat-Treated Electroless Ni Coatings Embedded with c-BN Nanoparticles

The nickel (Ni) coatings without and with embedded (5–7 vol. %) cubic boron nitride (c-BN) nanoparticles (10 nm in diameter) were deposited on carbon steel substrate by an electroless plating process. Coatings were tested in as-deposited and heat-treated (heating at 300 °C for 6 h) conditions. Coating structure characterisation was performed, as well as hardness and roughness measurements. Friction properties were tested in dry and in water (seawater) lubricated contact conditions, with bronze as a counter-body material. Both static and kinetic coefficients of friction were measured for two different surface texture preparations (initial and working). The first surface texture simulated the running-in condition, and the second surface texture represented the steady-state conditions. The enhancement of the abrasive and erosive wear resistance of heat-treated electroless Ni coatings with embedded c-BN nanoparticles was already proved in our previous studies. This study aims to investigate those influences on friction properties of electroless Ni coatings in different sliding conditions. The results show that the coefficients of friction did not differ too much between the coatings and that the surface roughness and presence of seawater had a much stronger influence.

Superb storage and energy saving separation of hydrocarbon gases in boron nitride nanosheets via a mechanochemical process

Light hydrocarbon olefin and paraffin gas mixtures are produced during natural gas or petrochemical processing. The petrochemical industry separates hydrocarbon gas mixtures by using an energy-intensive cryogenic distillation process, which accounts for 15% of global energy consumption [1]. The development of a new energy-saving separation process is needed to reduce the energy consumption. In this research, we develop a green and low energy mechanochemical separation process in which boron nitride (BN) powders were ball milled at room temperature in the atmosphere of an alkyne or olefin and paraffin mixture gas. BN selectively adsorbs a much greater quantity of alkyne and olefin gas over paraffin gases, and thus the paraffin gas is purified after the ball milling process. The adsorbed olefin gas can be recovered from the BN via a low-temperature heating process. The mechanochemical process produces extremely high uptake capacities of alkyne and olefin gases in the BN (708 cm3/g for acetylene (C2H2) and 1048 cm3/g for ethylene (C2H4)) respectively. To the best of our knowledge, assisted by ball milling, BN nanosheets have achieved the highest uptake capacities for alkyne/olefin gases, which are superior to all other materials reported so far. Chemical analysis reveals that large amounts of olefin gases were quasi-chemically adsorbed on the in-situ formed BN nanosheets via C–N bond formation, whereas small amount of paraffin gases was physically adsorbed on BN nanoparticles. This scalable mechanochemical process has great potential as an industrial separation method and can realize substantial energy savings.

Improvement of structural, thermal and mechanical properties of epoxy composites and bonded joints exposed to water environment by incorporating boron nanoparticles

This research aims to investigate the effects of hexagonal boron nitride (h-BN) and hexagonal boron carbide (h-B 4 C) nanoparticles on the epoxy composites and single lap joints against hydrothermal ageing and resultant degradations of mechanical, thermal and structural properties. The undoped, h-BN and h-B 4 C nanoparticles doped epoxy composites and single lap joints were fabricated and then exposed to distilled water for 20, 40, and 60 days. Water absorption, FT-IR, SEM, DSC, DMA and tensile tests were performed to characterize the epoxy composites after hydrothermal ageing. In addition, a tensile test was performed to determine the failure load of the single-lap joints bonded with undoped, h-BN and h-B 4 C doped epoxies. It was seen from the experimental results that the ageing time and the doping of boron nanoparticles into the epoxy resin changed the rates of degradation. The degradation in the mechanical and thermal properties of h-BN and h-B 4 C nanoparticles doped epoxy composites occurred to a lower extent than undoped epoxy. After 60 days of the hydrothermal ageing, the storage modulus and the tensile strength of undoped epoxy composites decreased by approximately 30% and 29%, while these degradation rates were determined as 16% and 18% in the h-BN doped epoxy composites, respectively. Similarly, the degradation of thermal and mechanical properties of h-B 4 C nanoparticle doped composites is lower than that of undoped composites. Additionally, it was observed that the joints bonded with h-BN and h-B 4 C doped epoxies exhibited better mechanical performance after the hydrothermal ageing. The failure load of the undoped, h-BN and h-B 4 C doped epoxy joints was decreased by 34%, 19% and 20% at the end of 60 days of ageing, respectively. The results of this research work are thought to benefit the wide and safe application of epoxy resin systems in engineering applications.

Mechanical Characterization of Graphene-Hexagonal Boron Nitride-Based Kevlar-Carbon Hybrid Fabric Nanocomposites.

Polymer nanocomposites have been gaining attention in recent years. The addition of a low content of nanomaterials into the matrix improves mechanical, wear, thermal, electrical, and flame-retardant properties. The present work aimed to investigate the effect of graphene and hexagonal boron nitride nanoparticles on Kevlar and hybrid fiber-reinforced composites (FRP). Composites are fabricated with different filler concentrations of 0, 0.1, 0.3, and 0.5 wt.% by using a hand layup process. Characterizations like tensile, flexural, hardness, and impact strength were evaluated separately, heat deflection and viscosity properties of the epoxy composites. The dynamic viscosity findings indicated that a higher concentration of filler material resulted in nano-particle agglomeration. Graphene filler showed superior properties when compared to hexagonal boron nitride filler. Graphene showed optimum mechanical properties at 0.3 wt.%, whereas the hBN filler showed optimum properties at 0.5 wt.%. As compared to Kevlar composites, hybrid (carbon–Kevlar) composites significantly improved properties. As compared to graphene-filled composites, hexagonal boron nitride-filled composites increased scratch resistance. Digimat simulations were performed to validate experimental results, and it was observed that hybrid fabric composites exhibited better results when compared to Kevlar composites. The error percentage of all composites are within 10%, and it was concluded that hybrid–graphene fiber composites exhibited superior properties compared to Kevlar composites.

Effect of cubic and hexagonal boron nitride additions on the microstructure and properties of bulk MgB2 superconductors

MgB2 is a promising material for intermediate temperature applications where conventional low temperature superconductors cannot be used, especially if the range of magnetic fields over which is has acceptable current carrying performance can be expanded. However, its applicability is limited by poor properties at elevated magnetic fields. Carbon-based dopants can be used to dramatically improve the high-field performance of MgB2, but at the cost of a reduction in the superconducting transition temperature (T c) that limits the operation temperature to 20 K or below. Here we report an enhancement of superconducting performance of MgB2 with the addition of cubic and hexagonal boron nitride (BN), without any significant reduction in T c. Ex-situ bulk samples of MgB2 with two forms of BN addition were manufactured by the field assisted sintering technique after high energy ball milling of powder mixtures. We find that hexagonal BN (hBN) nanoparticles mixed homogenously with MgB2 powder react much more easily to produce Mg–N–B impurities than larger cubic BN (cBN) particles (∼10 µm) under the same processing conditions. The addition of 1 wt% hBN or 5 wt% cBN combined with 6 h of milling has been demonstrated to improve the critical current density (J c) of MgB2 over the entire magnetic field range. It is proposed that the nano-sized Mg–N–B impurities, that typically reside at MgB2 grain boundaries, increase pinning strength by introducing additional flux pinning centres. In addition, excess Mg may benefit the low-field performance by improving the connectivity. This work shows the significance of microstructural characterization on inhomogeneous superconducting materials to analyse their performance.

Effect of UV irradiation on epoxy adhesives and adhesively bonded joints reinforced with BN and B4C nanoparticles

The effect of environmental conditions on epoxy polymers restricts their usage in outdoor applications. Although many studies of epoxy adhesive and adhesively bonded joints under different environmental conditions such as saltwater, acid environment, and high temperature have been carried out, the effect of ultraviolet (UV) irradiation has not been examined to date in detail. The primary focus of this research is to improve the usage limitations and reduce the degradation due to UV irradiation by incorporating boron nanoparticles into epoxy resin. Epoxy adhesives were reinforced with 2% by weight functionalized boron nitride (BN) and carbide (B4C) nanoparticles in accordance with this purpose. Bulk adhesives and adhesively bonded aluminium joint specimens were produced with unreinforced and boron nanoparticles reinforced adhesives. Subsequently, produced specimens (bulk adhesives and adhesively bonded joints) were subjected to 480, 960, and 1440 h of continuous UV irradiation chamber and characterized to specify the effects of boron nanoparticles on the degradation. The changes and degradations caused by UV irradiation on bulk epoxy adhesives were determined by FT-IR, SEM, DSC, DMA, and tensile test techniques. Similarly, the static tensile test was applied to determine the effect of UV irradiation on adhesively bonded joints. When the experimental results obtained from the research were examined, it was observed that the bulk adhesives and adhesively bonded joints degraded under UV irradiation depending on the UV exposure time. However, the degradation rate was decreased by the nanoparticle reinforcement to the epoxy adhesive. The glass transition temperature values of the adhesives increased depending on the exposure time in line with the temperature effect of the environment. Accordingly, while the elasticity modulus and storage modulus of the adhesives increased, their tensile strengths showed a decreasing trend depending on the exposure time to UV irradiation. Similarly, the adhesively bonded joints showed a decrease in failure load at the end of 480, 960, and 1440 h due to the thermal effect rather than UV rays. The degradation behaviour observed in mechanical properties was obtained at higher rates in unreinforced specimens.

A novel temperature-responsive mixed matrix ultrafiltration membrane based on boron nitride nanomaterial

A novel mixed matrix membrane was prepared by blending polysulfone with two-dimensional boron nitride followed by its hydroxyl functionalization. Prepared nanocomposite membranes were characterized for the surface morphology, surface roughness, zeta potential and hydrophilicity. Uniform dispersion of boron nitride nanoparticles in polysulfone matrix and consequent changes in membrane properties were confirmed by scanning electron microscope images, atomic force microscope images, zeta potential, contact angle analysis, and X-Ray photoelectron spectroscopy. Differential scanning calorimetry (DSC) technique was used to determine the glass transition temperature (Tg) of the modified membrane and the results revealed the presence of BN in the membrane matrix. The highest water flux of 329.52 Liters per sqm per hour (LMH) was obtained in case of PS/BN (1%) as compared to 151.87 LMH of virgin membrane and Albumin rejection also increased by nanocomposites membranes up to certain concentration of Boron nitride. A unique behavior of temperature responsiveness of nanocomposite membrane was observed, where a steep increment in permeate flux by 205% at higher temperature was noted as compared to the virgin Polysulfone membrane where only 103% increase was recorded for the same temperature range. Moreover, the water uptake capacity of nanocomposite membranes were measured to understand the changes with nanomaterial incorporation. The membrane showed a good promise for high-temperature separation applications.

The paramagnetic approach of the color-changing of nano h-BN particle under the neutron irradiation

Paramagnetic centers and their character in the nanocrystalline h-BN particles were investigated before and after neutron irradiation . Color changing in a neutron irradiated h-BN nanoparticles was analyzed by new formed EPR signal. Electron Paramagnetic Resonance (EPR) analysis was performed at room temperature in the range of 500 ÷ 5500 G with 3300 G central line. The 0.3270–0.3370 T region, where more paramagnetic centers are observed, was additionally considered. New paramagnetic centers formed by the neutron flux in h-BN nanoparticles have been explained by EPR spectra . • After neutron irradiation light-pink color-changing of BN nanoparticles is symmetrically observed EPR signal. • Stable signals were detected in accordance with the parameters g X = 2.003252, ΔB X ∼22G and g Y = 2.003252, ΔB Y ∼110G. • The transition from B 2 N 4 to B 3 N 3 structure is pssible with thermal processing.