Mechanical Properties Of Nanocomposites Research Articles

(Digital Presentation) Anelasticity, Mechanical Spectroscopy, Internal Friction in Radiation and Structural Functionalized Nanocomposites of Multiwalled Carbon Nanotubes and Polyamide, Polyvinylchloride, Polyethylene, SiO2

Experimental Methods Ultrasound (US) impulse-phase method using computerized “KERN-4” with frequencies f┴ ≈ 0,7 MHz and f║ ≈ 1 MHz was used [1,2]. The measured velocity error was equal to ΔV/V ≈ 1,5%. Results and Discussion The influencing of ultrasonic deformation εUS was researched on mechanical properties of nanocomposite. The important value is in position of formation in the polymeric matrix of molecular structures, as multiwalled carbon nanotubes serve as the centers of crystalline phase nanocomposite origin. Amplitude-dependent internal friction (ADIF) measurement can be used as the highly sensitive method of monitoring the nanoplastic deformation eND of nanocomposites. ADIF measurement makes it possible to record the moment of dislocation segments LC separation from stoppers. Internal friction (IF) is caused by various relaxation processes that are related to nanocomposites structure defectiveness. Even rather small strain can collect up in non-ideal nanocomposites, changing their anelastic and elastic characteristics. One of the ways to purposefully change the properties of multiwalled carbon nanotubes in order to use them in nanoelectronics is to introduce impurities of other elements. It was found that as the result of the structural defect annealing IF background Q0 -1 significantly decreases during measuring of IF temperature dependences Q-1(T), which indicates the improvement of nanocomposite structure. The samples were prepared by ultrasonic dispersion using digital ultrasonic (US) bath CE-6200A with power W = 70 W at frequency f ≈ 42 kHz [1,2]. Illustration of the window for processing data of quasilongitudinal elastic waves velocity measuring V║ = 3244 ± 10 m/sec m/sec in nanocomposite polyamide (PA-6) (NH(CH2)5CO)n + 0,1% multiwalled carbon nanotubes (MCNT) by by pulse-phase US method at frequency f║ ≈ 1 MHz after electron irradiation with dose De- ≈ 10 MRad with energy Ee- ≈ 2,0 MeV is represented in Fig. 1. Fig.1. Illustration of the window for processing data of quasilongitudinal elastic waves velocity measuring V║ = 3244 m/sec in nanocomposite polyamide (PA-6) (NH(CH2)5CO)n + 0,1% MCNT by pulse-phase US method at frequency f║ ≈ 1 MHz after electron irradiation with dose De- ≈ 10 MRad.Poisson coefficient μ and elastic modulus E completely characterize the elastic properties of polymer nanocomposite. Poisson coefficient μ - elastic value of ratio of relative transversal compression e^ to relative longitudinal lengthening e║ [1]. One oscillator produces 3 waves: 1 longitudinal and 2 transversal. Debye temperature θD was determined after the formula [2], where kB - Boltzmann constant, h - Plank constant, NA - Avogadro number, A - middle gram-molecular mass, V║ - quasilongitudinal US velocity, V┴ - quasitransversal US velocity.Complex elastic modulus of nanocomposite polyamide-6 (PA-6) (NH(CH2)5CO)n + % MCNT E* is equal to the sum of elastic dynamic modulus E’ = rV║ 2 and loss modulus E” = E’d [2], where δ - logarithmic decrement of US attenuation, ρ - nanocomposite density, V║ - longitudinal US elastic waves velocity, Q-1 - internal friction, where α - US attenuation coefficient, λ - US wavelength, f - US frequency. Internal friction is equal Q-1 = δ/π. The logarithmic decrement of attenuation δ of US oscillations with amplitude A = A0e- d x is equal: δ = ln(An+1/An). Conclusions The presence of the strong interaction for nanocomposite between polyamide-6 (NH(CH2)5CO)n and multiwalled carbon nanotubes was confirmed.The increase of the nanocomposite crystallinity degree at growth of multiwalled carbon nanotubes concentration filling with the nanotubes of matrix results in the decline of content of organized phase.The phenomenon of change of Poisson coefficient m, Debye temperature θD, dynamic elastic modulus E’ = rV║ 2, dynamic shear modulus G = rV^ 2 under the influence of radiative electronic e- radiation is caused by the appearance of primary radiation defects (RD). As the result of interdefect interactions primary RD form secondary RD. Acknowledgments This work has been supported by the Ministry of Education and Science of Ukraine: Grant of the Ministry of Education and Science of Ukraine for the prospective development of the scientific direction “Mathematical sciences and natural sciences” at Taras Shevchenko National University of Kyiv. References Onanko, A.P., Kuryliuk, V.V., Onanko, Y.A. et al. Features of inelastic and elastic characteristics of Si and SiO2/Si structures. Journal of Nano- and Electronic Physics13(5), 05017(5) (2021).Onanko, A.P., Kuryliuk, V.V., Onanko, Y.A. et al. Mechanical spectroscopy and internal friction in SiO2/Si. Journal of Nano- and Electronic Physics14(6), 06029(7) (2022). Figure 1

Failure investigation of woven scarf-repaired laminates reinforced with nanoparticles: Experimental and numerical investigations

This study explores the efficacy of multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) as nano-reinforcement for the epoxy adhesive layer in scarf joints and 3D scarf-repaired laminates subjected to tensile loading. Experimental characterization of pure epoxy and nanocomposite mechanical properties was validated using the Mori–Tanaka method (incorporating agglomeration effects). A 3D finite element model considering material non-linearity and strain-based damage was employed to investigate joint failure behaviour, validated for 0.5 vol% MWCNT and GNP concentrations. A subsequent parametric study explored the influence of scarf angle, nanoparticle concentration, and patch configuration on 3D repaired specimens. The results suggest a 2.86° scarf angle with a [(+45/−45)]4s patch configuration reinforced with 1 vol% MWCNTs and 0.5 vol% GNPs exhibits the highest tensile strength improvement.

Fabrication and characterization of PMMA denture base nanocomposite reinforced with hydroxyapatite and multi-walled carbon nanotubes

Polymethyl Methacrylate (PMMA) is still one of the most popular denture base materials in dentistry due to its superior mechanical properties. However, its long-term use can result in defects such as low flexural strength and brittleness, which can be addressed by strengthening its mechanical properties. In this study, the effect of adding non-modified and modified hydroxyapatite nanoparticles (HaP NPs) and multi-walled carbon nanotubes (MWCNTs) on the thermal and mechanical properties of PMMA denture base materials was investigated. First, the modified HaP (MHaP) NPs and modified MWCNTs (MMWCNTs) were prepared by a vinyltriethoxysilane (VTES) agent. Then, two-component PMMA-HaP/MHaP and PMMA-MWCNT/MMWCNT, and three-component PMMA-HaP/MHaP-MWCNT/MMWCNT composite samples were fabricated from commercial dental heat-curing acrylic resin (Acrosun) with different amounts of HaP/MHaP (3, 5, and 10 wt%) and MWCNT/MMWCNT (0.25, 0.5, and 1 wt%). The samples were investigated by Simultaneous Thermal Analysis (STA), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-Ray Spectroscopy (EDS), Dynamic Mechanical Analysis (DMA), and Three-point flexural test. It was observed that surface modification of NPs improved the interaction of NPs and polymer chains in the matrix and resulted in better mechanical properties of nanocomposites. In the sample containing 3 wt% MHaP and 0.25 wt% MMWCNT, the flexural strength and flexural modulus were increased by 45 % and 42 % compared to the control sample, respectively, and the glass transition temperature (Tg) based on the DMA test was 152.7 °C, which was higher than in the other samples. The results of MTT assay studies indicated that adding MHaP and MMWCNT enhanced cell viability. In the PMMA- 3 wt% MHaP- 0.25 wt% MMWCNT composite, the cell viability was increased to 153.75 ± 9.7 % and confirmed its biocompatibility properties.

Porous liquids assisted in-situ generated Co-LDH@MOF heterostructure with abundant defects for flame retardant and mechanical enhancement in polyurea composites

Preventing aggregation and inducing homogeneous dispersion of flame retardant nanofillers is critical to enhance the fire safety and mechanical properties of nanocomposites. Although chemical modifications are commonly used to improve the filler’s compatibility with the polymer chain, such methods are often cumbersome and limited. Herein, porous liquids (PLs) with flame retardant function were constructed in which porous defect-Co-LDH@ZIF-67 (d-LDH@ZIF) heterostructure particles were converted into liquid materials by electrostatic interaction with a large-volume solvent. This is also the first report of PLs in the field of flame retardant. Specifically, the d-LDH@ZIF heterostructure was designed by defect engineering and in situ growth strategy to compensate for the low catalytic activity and specific surface area of Co-LDH, and to serve as a rigid porous framework for PLs. Numerous cobalt/oxygen vacancies and lattice defects in the d-LDH@ZIF heterostructure have also been proven to confer higher flame retardancy relative to Co-LDH. d-LDH@ZIF porous liquids (PLs-d-L@Z) presents favorable liquid characteristics and achieves a monodisperse state in the polyurea matrix. The limiting oxygen index of polyurea composites blended with 20 wt% PLs-d-L@Z (3 wt% d-LDH@ZIF content) can be increased to 24.2 % and pass the V-0 rating in the UL-94 test. Moreover, the peak of heat release rate, total heat release, and total smoke production are reduced by around 40.4, 27.0, and 39.9 %, respectively, compared to neat polyurea. Emphatically, the PLs-modified polyurea composites exhibit significantly improved mechanical and impact resistance properties, as well as favorable chemical resistance. This strategy of liquefying solid flame retardant fillers will open an avenue to the design of functional nanomaterials for fire safety and other potential applications.

An experimental-analytical investigation of particle size effect on the mode I fracture behavior of polymer/graphene nanocomposites

Due to their outstanding specific mechanical and functional properties, the engineering use of polymer nanocomposites and their carbon composites is becoming increasingly pervasive. Current and potential applications include micro- and flexible electronics, energy storage devices, and the use as reinforcement for advanced carbon fiber composites for light-weighting of aerospace and mechanical structures, thereby reducing their fuel consumption and carbon footprint. While a large amount of data and models regarding the effect of the weight fraction of nanoplatelets on the mechanical properties of nanocomposites is currently available in the literature, an aspect often overlooked is the scaling of the fracture behavior and the related particle size effects. Not only is the lack of understanding of size effects in nanomaterials hindering the full exploitation of their properties, it is also a serious issue since the design of large nanocomposite structures or small-scale electronic components requires capturing the scaling of their mechanical properties and developing predictive capabilities. This paper aims at filling this knowledge gap by proposing a novel analytical and experimental approach to investigate particle size effects in nanocomposites at and leveraging the acquired knowledge to improve their fracture properties, from the nanoscale all the way to the macroscale. To this end, crack initiation fracture toughness data for graphene/epoxy nanocomposite are presented as a function of nanoparticle size and weight fraction and compared with model predictions using a novel analytical model based on enhanced crack-tip shielding effect due to the reduced nanoparticle size. Extensive fracture test data are presented for model calibration and model verification.

Preparation and characterization of bamboo based nanocellulose by ball milling and used as a filler for preparation of nanocomposite

In this research, bamboo-based nanocellulose was prepared and characterized using high-speed ball milling to reduce initial bamboo powder particle size for potential use in nanocomposites. FTIR analysis revealed structural modifications, including increased cellulose content and decreased lignin content post-treatment. XRD analysis indicated a shift from cellulose I to cellulose II, suggesting altered crystallinity and hydrogen-bonding networks. SEM analysis revealed distinct morphological changes between untreated and NaOH-treated bamboo fibers, with the latter exhibiting surface modifications indicative of effective treatment. Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM) images demonstrated a reduction in particle size to approximately 80 nm, with reduced aggregation and individualized nanofibrils. Tensile tests of bamboo nanoparticle-epoxy biocomposites with varying weight percentages (0.5 %, 1 %, 1.5 %, and 2 %) of nanoparticles showed enhanced tensile strength up to 1.5 % loading (83.92 ± 1.74 MPa), but a decrease at 2 % loading (70.24 ± 1.80 MPa), indicating increased strain-to-failure. SEM and TEM images illustrated a homogeneous distribution at 1.5 wt%, but increased agglomeration at higher contents, impacting microstructure. This study underscores bamboo-derived nanocellulose's potential for tailored applications and improved mechanical properties in nanocomposites, highlighting the critical role of filler content in material performance and microstructure.

Emerging Mo-doped MgAl-LDH lamellar/carbon nanotubes as 3D sustainable nanohybrid for designing a durable smart anti-corrosion composite

This paper focused on the utilization of 3D hybrid nanocomposites composed of layered double hydroxides (L) containing sodium molybdate (SM), which are chemically bonded with functionalized multi-walled carbon nanotubes (FCN), as nanocarriers for smart corrosion prevention. The SM molecules were loaded into the L, and L/FCN nanocarriers by an anion exchange process, and then the 3 synthesized nanoparticles (L, SM-L, and SM-L/FCN) were characterized. Based on the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PD) tests' outcomes, the maximum corrosion prevention efficiency (about 90.88 %) belongs to the SM-L/FCN nano reservoir containing saline extract. Additionally, for the epoxy phase, the EIS results (on the intact and scratched specimens) revealed a significant diminish in the chloride and water penetration into the epoxy coating during 63 days of immersion for intact and 24 h for scratched states. EIS results indicated the enhancement of the charge transfer resistance (Rct) of the scratched coatings, from 17.42 kΩ.cm2 for the EP sample to 72.47 kΩ.cm2 for the SM-L/FCN/EP one in long immersion times, revealing the self-repairing behavior of the designed coating. The results of intact coating revealed that the Log (|Z|0.01 Hz) value reached 10.63 in long immersion time indicating a decreased occurrence of coating disbondment attributed to the electrolyte infiltration and corrosion of the underlying metal substratum. According to the pull-off and cathodic disbonding tests results, there was an enhancement in adhesion (51.5 % decrease in loss of adhesion strength, & a 52 % decline in diameter of cathodic disbondment), and a strong interaction between the interface of epoxy and substratum. According to the mechanical tests (tensile and DMTA) results the incorporation of L and FCN nanoparticles into the SM-L/FCN sample enhanced the nanocomposite's mechanical properties. The tensile test showed an increase in ultimate tensile strength (σUTS) and elongation at break (Ɛb) of 130.61 % and 107.59 %, respectively, compared to the pure epoxy (EP) sample. Additionally, the dynamic mechanical thermal analysis (DMTA) test indicated a 144 % increase in crosslinking density for the SM L/FCN sample compared to the neat epoxy.

Mechanical and fracture behaviour of pristine and defective single/bi-crystal graphene/Ti nanocomposites using molecular dynamics simulations

Metal matrix nanocomposites (MMNCs) are emerging as lightweight but strong propositions with high specific strength and elastic modulus for specific design applications. In the present paper, single-crystal (GrNSs) and bi-crystalline graphene nanosheets (5|7GrNSs) were reinforced into titanium (Ti) matrices to investigate the mechanical and fracture characteristics of Ti-based MMNCs i.e. TiGrNCs and 5|7TiGrNCs, using molecular dynamics (MD). Based on our findings it can be observed that the use of GrNSs helps improve the strength of Ti in a significant manner. The results further demonstrate that the presence of grain boundaries (GBs) did not exert a significant impact on the mechanical properties of nanocomposites (NCs). Moreover, the presence of vacancies and grain boundaries did not deteriorate the mechanical properties of NCs in a deleterious manner. These outcomes will help in the development of NCs that are both lightweight and structurally stronger for the automotive, marine, and aerospace industries.

The Influence of Carbon Nanotubes on the Physical and Chemical Properties of Nanocomposites Based on Unsaturated Polyester Resin

The new actual scientific direction is in the development of different nanocomposites and the study of their medical–biological, physicochemical, and physicomechanical properties. One way to expand the functionality of nanocomposites and nanomaterials is to introduce carbon nanostructures into the polymer matrix. This study presents the properties of unsaturated polyester resins (Estromal, LERG S.A.) based on PET recyclate with multi-walled carbon nanotubes (MWCNTs): their mechanical and thermomechanical characteristics, resistance to ultraviolet radiation (UV-vis), and chemical resistance properties. The properties of the obtained materials were characterized using physical–chemical research methods. The changes in the properties of the composites for MWCNT content of 0.1, 0.3, and 0.5 wt % were determined. The results showed positive influences on the thermomechanical and mechanical properties of nanocomposites without significant deterioration of their gloss. Too much CNT added to the resin leads to heterogeneity of the composite structure.

Investigation of nanocomposite system with long-chain phosphorus-containing intercalator-modified montmorillonite nanosheets

The biodegradable polyester polybutylene adipate-co-terephthalate (PBAT) is a synthetic material that can melt and ignite easily when exposed to fire. Herein, we synthesized a long-chain phosphorus-containing intercalator by grafting 9,10-dihydro-9-oxa-10-phos-phaphenanthrene10-oxide (DOPO) onto long-chain quaternary ammonium salts (BHMDAC). Then inserted it into the sodium-based montmorillonite (MMT) nanosheets at the ratio of 25.9 wt% to obtain organic modified nanosheets. Subsequently, they were mixed into the PBAT matrix, and a series of performance such as microscopic dispersion, thermal stability, flame retardancy, mechanism and mechanical properties of nanocomposite were investigated. Compared with PBAT (1138.42 kW/m2), PBAT/MMT-(DOPO-BHMDAC) 5 wt% exhibited the lowest peak heat release rate value (508.04 kW/m2), which was reduced by 55.37 %. After adding 1 wt% MMT/DOPO-BHMDAC, the tensile strength of the sample increased from 25.1 MPa to 32.0 MPa, and the elongation at break increased to 826 %. This work provides a new perspective for future research on high-performance degradable polyester materials.

The Effect of Hybrid B4C and Si3N4 Nanoparticles on the Mechanical and Physical Properties of Copper Nanocomposites

This study investigated the effects of reinforcing pure copper with hybrid B4C and Si3N4 nanoparticles on the mechanical and physical properties of the nanocomposite matrix. The composite matrix was prepared using the powder metallurgy (PM) method, allowing uniform nanoparticle dispersion within the copper matrix. The PM method was a practical approach for achieving a homogeneous and good dispersion of the reinforcing particles in the matrix while controlling the porosity and improving the microstructure of the fabricated composite matrix. The addition of B4C and Si3N4 are both very hard and dense materials. When added to a material, they can fill voids and reduce porosity. This can lead to significant improvements in the material’s mechanical properties. The study found that adding hybrid B4C and Si3N4 nanoparticles enhanced the microhardness and mechanical properties of the nanocomposites. The improvements in the mechanical and physical properties of such composites containing 5% B4C were 21.6% and 18.4% higher than the copper base alloy. The findings suggest that including ceramic particles is a viable strategy for enhancing the mechanical characteristics of copper in its pure form. For example, adding 5% B4C particles to copper resulted in a 23% increase in Young’s modulus of the material while reducing electrical conductivity by 4.6%. On the other hand, the hybrid composite Cu/5%B4C + 2.5%Si3N4 showed a 32% improvement in Young’s modulus and 71% in the microhardness value compared to the base metal. This makes it a promising option for various engineering applications, such as high-performance electrical contacts and bearings.

Application of Vietnamese Nano Graphene as SBR Rubber Reinforcement for Abrasion Resistance Conveyors

Graphene has been extensively considered as an ideal additive to improve the mechanical properties of many composite materials, including rubbers, because of its novel strength, high surface area, and remarkable thermal and electron conductivity. Styrene Butadiene Rubber (SBR) is considered a good material for abrasion resistance conveyors in industries. However, the mechanical properties of SBR still need to be improved. This study shows the enhancement of Vietnamese nano graphene (GNPs) on mechanical properties of SBR rubber such as tensile strength, tear strength, abrasion resistance, and adhesion strength. The distribution of the Dioctyl Phthalate (DOP)-modified GNPs in the SBR matrix was investigated using scanning electron spectroscopy. Results show a significant increase in SBR/GNPs nanocomposite mechanical properties with the presence of GNPs (tensile strength, and tear strength increased by 29.67% and 31.89% respectively in comparison with SBR rubber without GNPs, and abrasion weight loss was decreased by 30.84% in comparison with SBR and adhesion strength with polyester fabric was 3 times higher than that of SBR). The evaluation of GNPs content in SBR/GNPs nanocomposite material was carried out. Results show that 0.5 phr of GNPs content in SBR/GNPs nanocomposite material was the optimal GNPs content with good mechanical properties, high abrasion resistance, and good adhesion with polyester fabric.

Effects of Orientation and Dispersion on Electrical Conductivity and Mechanical Properties of Carbon Nanotube/Polypropylene Composite.

The orientation and dispersion of nanoparticles can greatly influence the conductivity and mechanical properties of nanocomposites. In this study, the Polypropylene/ Carbon Nanotubes (PP/CNTs) nanocomposites were produced using three different molding methods, i.e., compression molding (CM), conventional injection molding (IM), and interval injection molding (IntM). Various CNTs content and shear conditions give CNTs different dispersion and orientation states. Then, three electrical percolation thresholds (4 wt.% CM, 6 wt.% IM, and 9 wt.% IntM) were obtained by various CNTs dispersion and orientations. Agglomerate dispersion (Adis), agglomerate orientation (Aori), and molecular orientation (Mori) are used to quantify the CNTs dispersion and orientation degree. IntM uses high shear to break the agglomerates and promote the Aori, Mori, and Adis. Large Aori and Mori can create a path along the flow direction, which lead to an electrical anisotropy of nearly six orders of magnitude in the flow and transverse direction. On the other hand, when CM and IM samples already build the conductive network, IntM can triple the Adis and destroy the network. Moreover, mechanical properties are also been discussed, such as the increase in tensile strength with Aori and Mori but showing independence with Adis. This paper proves that the high dispersion of CNTs agglomerate goes against forming a conductivity network. At the same time, the increased orientation of CNTs causes the electric current to flow only in the orientation direction. It helps to prepare PP/CNTs nanocomposites on demand by understanding the influence of CNTs dispersion and orientation on mechanical and electrical properties.

Enriching the microstructure of AZ91D alloy by nano MoO3 composites

In the present study, a vacuum-assisted stir-casting process was made to synthesize nano-molybdenum trioxide-strengthened magnesium alloy composites of varying weight proportions. Morphological analysis was used to study the uniform distribution of ceramic reinforcing particles in the synthesized magnesium nanocomposites. ASTM standards were used to examine the mechanical properties of the intermixture. It was observed that the nano-MoO3 ceramics were uniformly distributed within the matrix alloy, no residual porosity was observed, and the grain size of the intermixture was observed as 59.82 + /0.001 nm and due to enhanced grain refinement and interfacial reaction between the intermixtures, the mechanical properties of nanocomposites, such as tensile, compression, flexural and impact strengths, significantly increased over the as-cast magnesium alloy. The corrosion resistance was improved due to the reduced size of the Mg17Al12 phase and the more uniform dissemination of ceramic strengthening particulates. Further, the improved load-bearing capacity and transfer layer enriched the wear resistance of magnesium alloy nanocomposites for all weight proportions.

Compatibilization of Immiscible PA6/PLA Nanocomposites Using Graphene Oxide and PTW Compatibilizer for High Thermal and Mechanical Applications

The aim of this work is synthesis a novel nanocomposite containing Polylactide (PLA) and polyamide 6 (PA6) reinforced with graphene oxide (GO) and poly ethylene-butyl acrylate-glycidyl methacrylate) (PTW) compatibilizer during solvent-based method. For this purpose, GO was added to the nanocomposite with 0.1, 0.3, 0.5, 0.7 and 1 phr. Morphology, rheology and mechanical properties of nanocomposites were studied with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and (DMTA) which showed rougher fracture surface due to the presence of compatibilizer and an increase in the amount of graphene oxide and better dispersion of graphene oxide. The results of experimental and theoretical studies of mechanical properties showed that increasing the concentration of graphene oxide in the presence of PTW improved the tensile strength, impact strength and tensile modulus in the PA6/PTW/PLA system. The study of rheological properties showed an increase in storage modulus and complex viscosity, which also confirmed the role of PTW compatibilizer in better GO dispersion. So, PA6/PTW/PLA is a good candidate for mechanical and high thermal applications.

Mechanical and Thermophysical Properties of Epoxy Nanocomposites with Titanium Dioxide Nanoparticles

The introduction of nanoparticles and their homogeneous distribution in the polymer matrix, as well as their size, can have a significant effect on the mechanical properties of composite materials. In this work, we studied the mechanical characteristics of TiO2/epoxy nanocomposites with different contents and sizes of nanoparticles. The preparation of nanocomposites was carried out by a stepwise curing (at 90 and 160 °C) of ED-20 dianic epoxy resin in the presence of an aromatic hardener with the addition of titanium (IV) dioxide nanoparticles preliminarily synthesized by the plasma-chemical method. Ultrasonic dispersion was used to achieve a uniform distribution of nanoparticles in the polymer matrix. The chemical and phase composition, the structure of the as-synthesized TiO2 nanoparticles, and the resulting epoxy nanocomposites were characterized by elemental analysis, X-ray diffraction, transmission and scanning electron microscopy, and infrared spectroscopy. The mechanical properties of the nanocomposites were determined by the static tensile test, and the impact toughness was determined by the Charpy method. The glass transition temperature and thermal stability of the TiO2/epoxy nanocomposites were studied by thermal analysis methods. The formation of an interfacial layer between the TiO2 nanoparticles and an epoxy matrix has been shown for the first time by spectral methods. It is shown that the mode of curing and ultrasonic dispersion used, as well as varying the content and dispersity of the TiO2 nanoparticles, make it possible to obtain epoxy nanocomposites with simultaneously improved deformation-strength characteristics and impact strength values.

ZnS nanoparticles-tailored electric, magnetic and mechanical properties of nanocomposites

Zinc sulfide nanoparticles are embedded in unsaturated polyester resins (UPR) to form nanocomposites through the hand layup method. It is observed that dielectric, magnetic and mechanical properties improved due to strong interaction between ZnS nanofillers and UPR matrix. The amorphous nature of prepared nanocomposites confirmed by x-ray diffraction. SEM images revealed that UPR based nanocomposites exhibited well dispersion of ZnS nanoparticles. ZnS nanofillers (2.5 wt % concentration) exhibited significant/improved values of dielectric constant 309, ac conductivity 2.71 × 10−4S/cm, coercivity 259Oe, magnetic saturation 0.117 emu/g, and magnetic remanence 2.9 × 10−3emu/g. Whereas, good tensile strength 6.56 MPa and Young's modulus 99.7 MPa is observed at 2 wt % concentration of ZnS nanofillers. This work suggests that the prepared semiconducting ZnS nanofillers in the UPR matrix has potential as an electro-magnetic material with remarkable properties.

Effect of milling time on microstructural and mechanical properties of nano-Al2O3P/6061Al composites prepared by transient liquid-phase sintering

In this study, 5 vol% Al2O3 nanoparticles reinforced 6061 Al matrix nanocomposite was prepared by mechanical alloying the corresponding powders followed by hot-pressing. The effect of the milling time on the morphology of powder as well as the microstructure and mechanical properties of resulting nanocomposites was studied. The result shows that the effect of the milling time on the mechanical properties of nanocomposites comes from its effect on the distribution of Al2O3 nanoparticles in Al matrix. The long milling time is required to uniformly disperse Al2O3 nanoparticles within Al grains, in order to obtain good mechanical properties. The nanocomposite made from the powder milled for 50 h exhibits a tensile strength of 602 MPa and an elongation to failure of 8.8%, which are higher than those ever reported for the similar materials. The higher mechanical properties are mainly attributed to Orowan strengthening, grain boundary strengthening, and high dislocation density.

Nanocomposite fabrics with high content of boron nitride nanotubes for tough and multifunctional composites

Herein, we apply a one-step filtration method to obtain boron nitride nanotube (BNNT)-based fabrics incorporating high content of BNNTs and an adhesive thermoplastic polyurethane (TPU). The adsorption behavior of TPU on BNNTs of different qualities and on functionalized BNNTs was evaluated in a two-solvent system and contrasted with carbon nanotubes, pointing to differences in surface interaction. BNNT quality affected not only the nanocomposite mechanical properties but also the trends as a function of increasing TPU content and the adhesion to substrates. Samples containing higher quality BNNT materials showed up to 12-fold improvement in Young’s modulus, while functionalization improved the tensile toughness. Thermal conductivity varied between 1.5 and 3 W m−1 K−1 depending primarily on the BNNT content and without a pronounced effect from the quality of BNNTs. The BNNT-TPU fabric offers a promising format to exploit BNNTs within tough, electrically insulating, thermally conductive materials for heat dissipation within packaging or adhesive materials in electronics.Graphical abstract

Effect of adsorption, hardener, and temperature on mechanical properties of epoxy nanocomposites with functionalized graphene: A molecular dynamics study

Investigating Epoxy/hardener ratio and adsorption rate in epoxy/graphene oxide nanocomposites is of great importance, since these values can affect on the mechanical properties of the nanocomposite. In this study, molecular dynamics simulation was used to investigate and compare the mechanical properties of epoxy/graphene and graphene oxide nanocomposites (EPON 828, EPON 862, Epoxy Novolac, and Cycloaliphatic Epoxy with GNs and GO). Also, the effect of different weight percentages of graphene oxide (0,1,3 and 5 wt %), different weight percentages of epoxy compared to hardener, adsorption rate, and different temperatures were studied. The results showed that increasing the weight percentage of graphene oxide in epoxy matrices improved the adsorption rate between Epoxy/GO and the strength of nanocomposites. In addition, the amount of Young's modulus slightly decreased with increasing the temperature. Besides, the highest amount of Young modulus was obtained by increasing the weight percentage of epoxy to hardener at 63:37 wt %. Moreover, by comparing the mechanical properties of epoxy nanocomposites at 5 wt % graphene oxide, the highest Young modulus were found to be related to Novolac/GO 4.27 Gpa and EPON 862/GO 4.24 Gpa. This study contributes to a more comprehensive understanding on the behavior of the mechanical properties of epoxy/graphene oxide nanocomposites.