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1

Synthesis and Characterization of ZnO/MnFe2O4 Nanocomposites for Degrading Cationic Dyes

Yuniar, Agustina Tuty Emilia, Faizal Muhammad, Hariani Poedji Loekitowati

Journal of Ecological Engineering

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2023

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Vol. 24, nr 4

252--263

EN

By breaking down harmful dye waste into harmless components under the right irradiation sources, photocatalysis is an unorthodox but promising technique that can reduce industrial wastewater pollution, particularly in the textile industry. Synthetic textile dyes called cationic dyes must be handled carefully because they are poisonous and challenging to breakdown. Photocatalytic oxidation is a useful technique for eliminating hazardous organic pigments. This investigation aims to synthesize and characterize ZnO/MnFe2O4 nanocomposites as well as investigate the effects of varying ZnO:MnFe2O4 ratios, pH levels, doses, and irradiation times on band gap reduction and photocatalytic applications tested with cationic dyes, specifically methylene blue, under the illumination of sunlight. the co-precipitation approach for the manufacture of nanocomposites with different mole ratios of ZnO:MnFe2O4 (1:0.1; 2:0.1; 3:0.1). The component comprising the nanocomposite is ZnO/MnFe2O4, according to the results of the characterisation using XRD, SEM-EDX, FTIR, and BET. UV-DRS measurements of the band gap revealed that as ZnO was reduced, the band gap of the nanocomposite likewise decreased, from 3.35 eV to 2.78 eV. The greatest degradation of 93.2% was achieved for the degradation of 50 mg/L methylene blue (MB) dye with a catalyst dosage of 20 mg at a ratio of 1:0.2 for 50 minutes of irradiation. Since the point of zero charges (pzc) was reached at a pH of 7.8, a photodegradation adsorption-friendly solution pH of 8 was created.

2

Mechanical and Thermal Properties of HDPE Thermoplastic with Oil Palm Boiler Ash Nano Filler

Bukit Nurdin, Sinulingga Karya, Abd Hakim S., Sirait Makmur, Bukit Bunga Fisikanta

Journal of Ecological Engineering

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2023

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Vol. 24, nr 9

355--363

EN

This study aims to determine the mechanical and thermal properties of high density polyethylene (HDPE) thermoplastic nanocomposite with oil palm boiler ash (OPBA) filler made by coprecipitation method and synthesized with PEG 6000 surfactant with OPBA-PEG 6000 filler variations. The filler composition used was HDPE/OPBA (100/0, 98/2, 96/4, 94/6, 92/8, 90/10) wt%. Nanocomposites were prepared using a Rheomixer HAAKE Polylab OS System at 150°C and 60 rpm for 10 minutes. Mechanical properties of HDPE with increased OPBA filler content is beyond a certain threshold, the tensile strength of the HDPE composite may start to decrease. This decrease can be attributed to several factors. Firstly, as the filler content increases, the HDPE matrix may become less effective in transferring stress, resulting in reduced load-bearing capacity. This is confirmed from the SEM results that the filler agglomerates and cracks occur in the composite. The composite material may exhibit a lower Young’s modulus compared to pure HDPE with low Young’s modulus tend to have high elongation at break which indicatie a flexible and ductile composite. The melting point of peaks 1 and 2 on 0% filler and other fillers did not change significantly even at certain compositions the melting point decreased after adding filler.

3

Characterization of Nanocomposite Mixture Polyvinyl Alcohol and Rice Husk Ash

Sirait Makmur, Sinulingga Karya, Siregar Nurdin

Journal of Ecological Engineering

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2023

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Vol. 24, nr 11

268–-273

EN

Rice husk ash (RHA) nanoparticles were prepared to be applied as a filler in the formation of Polyvinyl Alcohol (PVA) nanocomposites. The manufacture of rice husk ash nanoparticles involved the Ball Mill method and the coprecipitation method, while the manufacture of Polyvinyl Alcohol nanocomposite membranes and rice husk ash was carried out by the sol-gel method. The results of XRD analysis using Match software indicated that the crystal structure of rice husk ash is monoclinic with a particle size of 16.55 nm. The mechanical test results obtained the largest elastic modulus of 29.28 MPa in 3% rice husk ash mixture, the largest tensile test of 8.83 MPa in 1% rice husk ash mixture, and the largest elongation at break of 82.08% in 4% rice husk ash mixture. The addition of rice husk ash as a filler can improve the mechanical properties of PVA/rice husk ash nanocomposites.

4

Experimental study of nano-composite materials on vibration responses

Mobark Haidal Faisal Helal, Fahdel Essam Z., Hussein Mustafa Turki, Mohamad Barhm

Diagnostyka

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2023

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Vol. 24, No. 3

art. no. 2023312

EN

This paper present of experimental and numerical study of nano Al2O3 cantilever beam for forced vibration, addressing an unexplored area in the existing literature. The proposed nano composite cantilever beam is modeled with hole and crack. The study is based on history loading calculation and composite morphology a global parameter, the transverse crack in nano composite cantilever beam was studied and analyzed experimentally using a four-channel dynamic signal acquisition (NI 9234) module for making high-accuracy measurements and its ideal for vibration applications. The relationship between the dispersion and interaction of the alumina nanoparticles within the cantilever beam and morphology of the solid, hole and crack composite has been identified. Furthermore, the influence of particles Al2O3 at different concentrations (0%, 1%, 3% and 4%) have been studied respectively. Supporting results proved that the crack and hole depth increases with increases of history loading. Nanoparticles dispersed within the specimen can increase energy dissipation during vibration, leading to improved damping characteristics. For future work, it is recommended to utilize statistical frequency domain input, such as Power Spectral Density (PSD), for assessing the structural response instead of employing time history loading.

5

Comparative performance assessment of nano-composite cathode of lmso-bscmf for low temperature solid oxide fuel cell applications

Subhashini P.V.C.K., Rajesh K.V.D.

Composites Theory and Practice

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2023

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R. 23, nr 4

235--238

EN

The development of novel cathode materials for low temperature solid oxide fuel cell (SOFC) applications is one of the significant research areas in materials engineering. In the current work, composite cathode materials were prepared by two different modes and the fuel cell performance was assessed using a gadolinium-doped ceria (GDC) electrolyte. Nanocomposite cathodes were fabricated using a lanthanum strontium manganite oxide (LSMO) powder of a 50-100 nm particle size and Ba0.5Sr0.5(Co0.2Mg0.8)0.2Fe0.8O3 (BSCMF) powder of a 1 μm particle size. The cathodes were prepared as layered composites and mixed composites. The electrochemical performance of the symmetric cells was investigated by electrochemical impedance spectroscopy (EIS) at the intermediate temperature of 700°C using air atmosphere. The cathode film coating on the electrolyte was sintered at three different temperatures (900, 950 and 1000°C) and the cell performance was assessed at 700°C. Lower polarization resistance (RP) values were recorded for the cell produced at 900°C. The RP of the nano-composite cathodes was measured as lower (2.72 Ω-cm2 for the layered composites and 1.76 Ω-cm2 for the mixed composites) compared with LSMO. Hence, the results demonstrate the potential of using an LSMO-BSCMF composite in the mixed mode as a cathode for low temperature SOFCs to achieve a lower polarization potential.

6

Leading-edge polymer/carbonaceous nano-reinforcement nanocomposites — opportunities for space sector

Kausar Ayesha, Ahmad Ishaq

Advances in Materials Science

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2023

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Vol. 23, nr 4(78)

99--122

EN

Carbonaceous or nanocarbon nano-reinforcement nanocomposites have been found as emergent candidates for aerospace industry. Consequently, the multifunctional nanocomposites have been fabricated using marvelous nanocarbon nanostructures like graphene, carbon nanotube, fullerene, carbon black, etc. Manufacturing techniques have also been engrossed for the formation of high performance engineering nanocomposites having fine strength, heat stability, flame resistance, and other space desired features. These practices include solution, in situ, and melt procedures, on top of specific space structural design techniques, for the formation of aerospace structures. The aerospace related material property enhancements using various carbonaceous nano-reinforcements depends upon the type of nanocarbon, dimensionality, as well as inherent features of these nanostructures (in addition to the choice of manufacturing methods). Furthermore, carbon nano-reinforcements have been filled, besides carbon fibers, in the epoxy matrices. Nanocarbon coated carbon fibers have been filled in epoxy resins to form the high performance nanomaterials for space structures. The engineering features of these materials have been experiential appropriate for the aerospace structures. Further research on these nanomaterials may be a key towards future opportunities in the aero systems. Additionally, the explorations on structure-property relationships of the carbonaceous nanocomposites have been found indispensable for the development of advanced aerospace structures.

7

Preparation of Environmentally Friendly Adsorbent Using Oil Palm Boiler Ash, Bentonite and Titanium Dioxide Nanocomposite Materials

Bukit Nurdin, Ginting Eva Marlina, Frida Erna, Bukit Bunga Fisikanta

Journal of Ecological Engineering

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2022

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Vol. 23, nr 12

75--82

EN

Using the products derived from agricultural wastes as low-cost adsorbent materials to remove organic or inorganic contaminants would be ideal, as these materials are readily available in many countries. This study aimed to prepare environmentally friendly adsorbents made from nanocomposite OPBA / Bentonite / TiO2. The coprecipitation method was used in preparing OPBA, and CTAB surfactant was added in bentonite preparation. Meanwhile, the manufacture of TiO2 was carried out using the sol-gel method. Characterization was done by XRD, FTIR, SEM, and BET. The adsorbent spectra did not show a significant shift in absorption where the O-H bonds were becoming weaker due to the presence of TiO2 in the interlayer of bentonite. Another possibility is due to the influence of calcination and heating. The O-H groups of H2O are hydroxylated and dehydrated from within between layers. The formation of the composite OPBA/TiO2/Bentonite does not change the crystallinity of TiO2 significantly. This proves that there is no decrease in photocatalyst activity after the addition of OPBA and bentonite. The morphology of the whole sample has a flake-like structure that has pores. The addition of OPBA into Bentonite/TiO2 causes a decrease in the specific surface area of the sample.

8

Effect of Cooling Rate on Mechanical Properties of New Multicomponent Fe-Based Amorphous Alloy During Annealing Process

Rezaei-Shahreza Parisa, Redaei Hossein, Moosavi Parisa, Hasani Saeed, Seifoddini Amir, Jeż Bartłomiej, Nabiałek Marcin

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 1

251--254

EN

Fe-based bulk metallic glasses (BMGs) have been extensively investigated due to their ultrahigh strength and elastic moduli as well as desire magnetic properties. However, these BMGs have few applications in industrial productions because of their brittleness at room temperature. This study is focused on the effect of cooling rate on the mechanical properties (especially toughness) in the Fe41Co7Cr15Mo14Y2C15B6 BMG. For this aim, two samples with the mentioned composition were fabricated in a water-cooled copper mold with a diameter of 2 mm, and in a graphite mold with a diameter of 3 mm. The formation of crystalline phases of Fe23(B,C)6, α-Fe and Mo3Co3C based on XRD patterns was observed after the partial crystallization process. To determine the toughness of the as-cast and annealed samples, the indentation technique was used. These results revealed that the maximum hardness and toughness were depicted in the sample casted in the water-cooled copper mold and annealed up to 928°C. The reason of it can be attributed to the formation of crystalline clusters in the amorphous matrix of the samples casted in the graphite mold, so that this decrease in the cooling rate causes to changing the chemical composition of the amorphous matrix.

9

Research on dielectric parameters of epoxy resin based nanocomposites using the impedance spectroscopy method

Dąda Anna, Błaut Paweł

Przegląd Elektrotechniczny

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2021

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R. 97, nr 12

234--237

EN

Due to the modern requirements regarding the reliability of electrical devices operation, research on improving the parameters of materials and insulation systems, in particular high-voltage ones, used in the production, transmission and distribution of electricity is still valid. One of the research directions is the development and application of insulating materials modified with nanofillers. The paper presents the results of stability studies of selected dielectric properties of samples of insulation materials based on epoxy resin modified with titanium dioxide TiO2 nanopowders. Changes in parameters caused by different wt% nanofiller content and their long-term stability after 10,000 hours from manufacturing are compared and analyzed.

PL

Współczesne wymagania dotyczące niezawodności pracy urządzeń elektrycznych powodują, że wciąż aktualnymi są badania dotyczące poprawy parametrów materiałów i układów izolacyjnych, w szczególności wysokonapięciowych, stosowanych w wytwarzaniu, przesyle i rozdziale energii elektrycznej. Jednym z kierunków badań jest opracowanie i zastosowanie materiałów izolacyjnych modyfikowanych nanowypełniaczami. Referat przedstawia wyniki badań stabilności wybranych właściwości dielektrycznych próbek materiałów izolacyjnych na bazie żywicy epoksydowej modyfikowanej nanoproszkami tlenku tytanu TiO2. Porównane są i analizowane zmiany parametrów powodowane różną zawartością wt% nanowypełniacza oraz ich stabilność długoczasowa po 10.000 godzin od wytworzenia.

10

A comprehensive Monte Carlo study to design a novel multi-nanoparticle loaded nanocomposites for augmentation of attenuation coefficient in the energy range of diagnostic X-rays

Sayyadi Elahe, Mesbahi Asghar, Zamiri Reza Eghdam, Nejad Farshad Seyyed

Polish Journal of Medical Physics and Engineering

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2021

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Vol. 27, Iss. 4

279--289

EN

Introduction: The present study aimed to investigate the radiation protection properties of silicon-based composites doped with nano-sized Bi2O3, PbO, Sm2O3, Gd2O3, WO3, and IrO2 particles. Radiation shielding properties of Sm2O3 and IrO2 nanoparticles were investigated for the first time in the current study. Material and methods: The MCNPX (2.7.0) Monte Carlo code was utilized to calculate the linear attenuation coefficients of single and multi-nano structured composites over the X-ray energy range of 10–140 keV. Homogenous distribution of spherical nanoparticles with a diameter of 100 nm in a silicon rubber matrix was simulated. The narrow beam geometry was used to calculate the photon flux after attenuation by designed nanocomposites. Results: Based on results obtained for single nanoparticle composites, three combinations of different nano-sized fillers Sm2O3+WO3+Bi2O3, Gd2O3+WO3+Bi2O3, and Sm2O3+WO3+PbO were selected, and their shielding properties were estimated. In the energy range of 20-60 keV Sm2O3 and Gd2O3 nanoparticles, in 70-100 keV energy range WO3 and for photons energy higher than 90 keV, PbO and Bi2O3 nanoparticles showed higher attenuation. Despite its higher density, IrO2 had lower attenuation compared to other nanocomposites. The results showed that the nanocomposite containing Sm2O3, WO3, and Bi2O3 nanoparticles provided better shielding among the studied samples. Conclusions: All studied multi-nanoparticle nanocomposites provided optimum shielding properties and almost 8% higher attenuation relative to single nano-based composites over a wide range of photon energy used in diagnostic radiology. Application of these new composites is recommended in radiation protection. Further experimental studies are suggested to validate our findings.

11

Carbon nanotubes-based sensor for ammonia gas detection – an overview

Nurazzi N. M., Demon Siti Zulaikha N., Halim Norhana A., Mohamad Syakir I., Abdullah Norli

Polimery

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2021

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T. 66, nr 3

175--186

EN

A sensitive, selective and reliable sensing techniques for ammonia (NH3) gas detection have been highly demanded since NH3 is both a commonly utilized gas in various industrial sectors, and considered as a toxic and caustic agent that can threat human health and environment at a certain level of concentrations. In this article, a brief on the fundamental working principles of sensor specifications of the analytes detection techniques relying has been reviewed. Furthermore, the mechanism of NH3 detection and recent progress in the development of advanced carbon nanotubes (CNTs)-based NH3 gas sensors, and their performance towards the hybridization with the conductive polymers was comprehensively reviewed and summarized. Finally, the future outlook for the development of highperformance NH3 sensors was presented in the conclusions part.

PL

Amoniak (NH3) to gaz powszechnie stosowany w różnych sektorach przemysłu, jest toksyczny i żrący, a powyżej określonego poziomu stężeń może zagrozić ludzkiemu zdrowiu i środowisku, dlatego ciągle trwają poszukiwania czułych, selektywnych i niezawodnych metod wykrywania gazów amoniakalnych. W niniejszym artykule dokonano przeglądu specyfikacji i podstawowych zasad działania czujników stosowanych w technikach wykrywania takich analitów. Szczegółowo przeanalizowano też mechanizm wykrywania i niedawny postęp w opracowywaniu zaawansowanych czujników do wykrywania gazu NH3 , opartych na nanorurkach węglowych (CNTs), a także ich modyfikacje obejmujące hybrydyzację z polimerami przewodzącymi. Przedstawiono również perspektywy rozwoju wysoko wydajnych czujników NH3.

12

Preparation and Characterization of ZnO-Zeolite Nanocomposite for Photocatalytic Degradation by Ultraviolet Light

Gayatri Rianyza, Agustina Tuty Emilia, Bahrin David, Moeksin Rosdiana, Gustini Gustini

Journal of Ecological Engineering

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2021

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Vol. 22, nr 2

178--186

EN

The increasing growth of the textile industry does not only provide benefits in the economic sector but also has the potential to damage the environment, because it generates the dye wastewater which is hard to eliminate. Procion red is one of the synthetic textile dyes that is toxic to the aquatic environment and it needs to be processed properly. The photocatalytic method of processing dye wastewater is the most effective, because it can remove the harmful pollutants in the dye wastewater. This study aimed to prepare and characterize the ZnO-Zeolite nanocomposites for photocatalytic applications tested with a 50 mg/L procion red dye sample. The nanocomposites consisted of the ZnO semiconductors and synthetic zeolite adsorbents prepared by using the sol-gel method. The dye degradation test was carried out under the irradiation conditions with ultraviolet (UV) lamp. Apart from the ZnO-Zeolite nanocomposite, testing was also carried out with the synthetic zeolite and ZnO. The results of SEM-EDX and XRD characterization proved that the nanocomposite forming components were ZnO and zeolite and could be seen from the resulting peaks. BET showed that the surface area value of the ZnO-Zeolite nanocomposite increased to 95.98 m2/g, the pore size of the ZnO-Zeolite nanocomposite was 4.42 nm, and the total pore volume was 0.08 cm3/g. The obtained average crystalline size of ZnO-Zeolite nanocomposite was 32.87 nm. The percentage of dye degradation using the ZnO-Zeolite nanocomposite for 120 minutes has reached 90.42%.

13

Influence of montmorillonite nanoparticles on thermal and mechanical properties of carbon-carbon hybrid composites based on phenolic-formaldehyde resin

Kateusz Filip, Korzec Tomasz, Zambrzycki Marcel, Cherniushok Oleksandr, Gubernat Maciej

Composites Theory and Practice

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2021

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R. 21, nr 3

96--101

EN

In this study, the effect of the addition of K-10 montmorillonite (MMT) nanoparticles on the mechanical and thermal properties of carbon-carbon composites were investigated. The composites were obtained using self-made prepregs with plain and twill 2/2, 600 g/m2 carbon fabric and phenolic-formaldehyde resin. The composites were obtained by the hot pressing technique, followed by carbonization in an inert argon atmosphere. Modified samples of the composites contained 5 wt.% MMT, homogenously dispersed in the ceramic carbon matrix. The mechanical properties, thermal conductivity and thermal capacity of the composites were determined. Raman spectroscopy and Fourier transform infrared spectroscopy were used to investigate the carbon matrix composition and structure. The results show that the addition of MMT nanoparticles increased Young’s modulus by 48%, Kirchoff’s modulus by 80.2%, but did not change the interlaminar shear strength nor the bending strength. The MMT influenced the carbon microstructure, changed the ID//IG Raman ratios, as well as the matrix composition. The addition of MMT also increased the low temperature regime of thermal conductivity and diffusivity of the samples.

14

Synteza nowych nanokompozytów chitozan/modyfikowany zeolit i ich wpływ na właściwości mechaniczne zapraw cementowych

Karakuş Selcan, Karapınar Işıl Sanrı, Pehlivan Ahmet Onur, Özsoy Özbay Ayşe Elif, Yazgan Utku

Cement Wapno Beton

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2021

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R. 26, nr 6

531--544

PL

W pracy przedstawiono nowy nanokompozyt zawierający biodegradowalny chitozan [CS] i modyfikowany zeolit [mZeo] jako eko-nanododatek do cementu oraz oceniono jego wpływ na właściwości mechaniczne zapraw cementowych. Proponowany nanokompozyt otrzymano dzięki synergicznej metodzie sonikacji mikrofalowej, a morfologię powierzchni i skład chemiczny nanokompozytów mZeo i CS/mZeo określono za pomocą SEM, FTIR, XRF i BET. Zbadano wytrzymałość na ściskanie i zginanie zapraw cementowych zawierających mZeo i CS/mZeo w ilości 0, 0,2, 0,5, 1 i 2 % masy cementu. Wyniki badań doświadczalnych wykazały poprawę wytrzymałości zapraw zawierających proponowany nanokompozyt. W niniejszej pracy po raz pierwszy podjęto próbę zastosowania zeolitu w nanoskali w kompozytach cementowych, a uzyskane dotychczas wyniki są bardzo obiecujące. Stwierdza się zatem, że proponowany nanokompozyt ma duży potencjał do zastosowania jako alternatywny eko-nanododatek do kompozytów cementowych.

EN

In this paper, a novel nanocomposite containing biodegradable chitosan [CS] and modified zeolite [mZeo] was introduced as a cement eco-nano additive and its effects on the mechanical properties of cement mortars were evaluated. The proposed nanocomposite was prepared by using a synergistic sonication-microwave method. The surface morphology and chemical compositions of mZeo and CS/mZeo nanocomposites were determined using SEM, FTIR, XRF, and BET. Compressive and flexural strength of cement mortars containing mZeo and CS/mZeo in ratios of 0%, 0.2%, 0.5%, 1% and 2% by mass, were investigated. Experimental results showed a significant improvement in the mechanical properties of mortars containing the proposed nanocomposite. The use of nanoscale zeolite in cementitious composites was attempted for the first time within this study and the results so far have been very promising. Therefore, it is concluded that the proposed nanocomposite has great potential to be used as an alternative eco-nano additive, for cementitious composites.

15

Characteristic of low-density polyethylene reinforcement with nano/micro particles of carbon black: a comparative study

Sabr O.H., Al-Mutairi N.H., Layla A.Y.

Archives of Materials Science and Engineering

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2021

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Vol. 110, nr 2

49--58

EN

Purpose: Low density polyethylene is commonly used polymer in the industry because of its unique structure and excellent overall performance. LDPE, is relatively low mechanical properties and thermal stability can sometimes limit its application in industry. Therefore, the development of particulate reinforced polymer composites is one of the highly promising methodologies in the area of next generation engineering products. Design/methodology/approach: Nano and Micro composite from low density polyethylene LDPE reinforced with different weight fraction of carbon black particles (CB) (2, 4 and 8)% prepared by first dispersion Nano and Micro carbon black particles CB in solvent and then mixing manually with low density polyethylene LDPE pellet and blended by twin-screw extruder, the current research study the mechanical properties (tensile strength, elastic modulus,and hardness), FTIR, DSC,and thermal conductivity of prepared nano and micro composites using two methodes and the morphological properties of nano-micro composites. Findings: The tensile strength of the LDPE/CB nano and micro composites improved at 2% and 4%, respectively, and decreasing at 8%, addition of carbon black nanoparticles led to increase the tensile strength of pure low-density polyethylene from 13.536 MPa to 19.71 MPa, and then dropping to 11.03 MPa at 8% percent,while the elastic modulus of LDPE/ CB nano and miro composites shows an improvement with all percentages of CB. The results show that the mechanical properties were improved by the addition carbon black nanoparticles more than addition micro- carbon black . FTIR show that physical interaction between LDPE and carbon black. The thermal conductivity improvement from 0.33 w/m.k for pur LDPE to 0.62234 w/m.k at 2% CB microparticle content and the reduced to 0.18645 w/m.k and 0.34063 w/m.k at (4 and 8)% micro-CB respectively , The thermal conductivity of LDPE-CB nano-composites is low in general than that the LDPE-CB microcomposite. DSC result show improvement in crystallization temperature Tc, melting temperature and degree of crystallization with addition nano and micro carbon black. Morever, SEM images revealed to uniform distribution and good bonding between LDPE and CB at low percentages and the precence of some agglomeration at high CB content. Research limitations/implications: This research studied the characteristics of both nano and micro composite materials prepared by two steps: mixing CB particles with solvent and then prepared by twin extruder which can be used packaging material, but the main limitation was the uniform distribution of nano and micro CB particles within the LDPE matrix. In a further study, prepare a blend from LDPE with other materials and improve the degradation of the blend that used in packaging application. Originality/value: LDPE with nanocomposites are of great interest because of their thermal stability, increased mechanical strength, stiffness, and low gas permeability, among other properties that have made them ideal for applications in the packaging and automotive industries. LDPE reinforcements nano-sized carbon black can have better mechanical and thermal properties than micron, resulting in less material being needed for a given application at a lower cost.

16

Creep Behaviors at 275°C for Aluminum-Matrix Nano-composite under Different Stress Levels

Azadi M., Behmanesh A., Aroo H.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 3

81--89

EN

Aluminum alloys, due to appropriate strength to weight ratio, are widely used in various industries, including automotive engines. This type of structures, due to high-temperature operations, are affected by the creep phenomenon; thus, the limited lifetime is expected for them. Therefore, in designing these types of parts, it is necessary to have sufficient information about the creep behavior and the material strength. One way to improve the properties is to add nanoparticles and fabricate a metal-based nano-composite. In the present research, failure mechanisms and creep properties of piston aluminum alloys were experimentally studied. In experiments, working conditions of combustion engine pistons were simulated. The material was composed of the aluminum matrix, which was reinforced by silicon oxide nanoparticles. The stir-casting method was used to produce the nano-composite by aluminum alloys and 1 wt.% of nanoparticles. The extraordinary model included the relationships between the stress and the temperature on the strain rate and the creep lifetime, as well as various theories such as the regression model. For this purpose, the creep test was performed on the standard sample at different stress levels and a specific temperature of 275 oC. By plotting strain-time and strain rate-time curves, it was found that the creep lifetime decreased by increasing stress levels from 75 MPa to 125 MPa. Moreover, by comparing the creep test results of nanoparticle-reinforced alloys and nanoparticle-free alloys, 40% fall was observed in the reinforced material lifetime under 75 MPa. An increase in the strain rate was also seen under the mentioned stress. It is noteworthy that under 125 MPa, the creep lifetime and the strain rate of the reinforced alloy increased and decreased, respectively, compared to the piston alloy. Finally, by analyzing output data by the Minitab software, the sensitivity of the results to input parameters was investigated.

17

Experimental study of nanocomposite hybrid adhesive-rivet joints

Nabibi Nabard, Ramezani Shadi

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 3

337--365

EN

The wide range of rivets usage goes back to the processes of manufacturing and repairing an aircraft fuselage. When it comes to structural joints, adhesive bonding is said to have some merits which overshadow other joining methods, such as bolting, riveting, and welding. Today, the applications of structural adhesives do not end in aerospace, but they also are ideal for the automotive industry, where the need is to join plates of dissimilar adhesives to produce lightweight car bodies. The hybrid joints also are one of the methods of joining different parts of the machine in a durable way in which some benefits such as the significant tensile strength, the dissipated energy, and higher reliability during long-term working stand out. In this research, the effect of rivets layout on strength and failure of nanocomposite rivet and hybrid adhesive-rivet joints through two experimental and numerical methods was evaluated. Also, using the artificial neural networks method, force–displacement curves for specimens were obtained. The results of the experimental tests and the finite element analysis showed that as the number of rivets increased in the joint of the nanocomposite components, the strength of the joint increased. The layout of the rivets has a significant effect on the strength of the rivet joint. According to the performed experiments for achieving the efficient strength in the hybrid joints for the nanocomposite plates, since the strength of the adhesive is very effective, adhesive selection and the appropriate number of rivets are the key factors. The fracture modes in the internal plates of nanocomposite joints (adhesive, rivet, and adhesive-rivet joints) were observed as follows: net-tension, bearing, shear-out, crack propagation, tearing, and shear in adhesive layers. Besides, the numerical model of the work is done using ABAQUS software. The results of software simulation in the numerical model are compatible with the experimental method’s findings. However, the agreement between the results of experimental and neural network methods is higher. Owing to the results of experiments, the polypropylene nanocomposite as well as the appropriate jointing method can be put forward in the structures of the automotive industry.

18

Synthesis of PMMA-HoVO4 nanocomposites by emulsifier-free emulsion polymerization: radical effects

Bulbul B., Pekcaliskan E. Y., Beyaz S.

Materials Science Poland

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2020

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Vol. 38, No. 1

143--150

EN

Poly(methyl methacrylate)-holmium orthovanadate (PMMA-HoVO4) nanocomposites were synthesized using emulsifierfree emulsion polymerization system in two ways. In the first one, the HoVO4 nanoparticle dispersion was added to the emulsion system before or after polymerization start (in situ polymerization). In the other one, nanoparticle dispersion and polymeric latex were mixed together at room temperature (blending). Crystalline HoVO4 nanoparticles (about 60 nm) were synthesized by coprecipitation method. Three different composite latexes were synthesized by varying the potassium persulfate concentration and the time of HoVO4 nanoparticles addition. According to the dynamic light scattering analysis, the size of the polymer beads in the latexes is between 244.8 nm and 502.5 nm and the PDI values are in the range of 0.005 to 0.206. Infrared spectral analysis showed that HoVO4 caused some changes in the structure of the polymer. Luminescence measurements attempted to determine optical properties of the nanocomposites. The results have shown that HoVO4 nanoparticles do not protect their structure due to the reaction with persulfate radicals but that they enter the polymer beads and change the luminescence properties of the polymer forming a new material with different properties.

19

Synthesis and characterization of poly(p-phenylenediamine): TiO2 nanocomposites and investigation of conducting properties for optoelectronic application

Baruah S., Devi N., Puzari A.

Materials Science Poland

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2020

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Vol. 38, No. 2

296--304

EN

Poly(p-phenylenediamine) is a potential precursor for designing of new materials for optoelectronic application. Synthesis and characterization of poly(p-phenylenediamine) – TiO2 nanocomposites has been demonstrated. Structural change observed due to the formation of nanocomposites was correlated with concomitant change in conducting behavior of the parent polymer. Polymer nanocomposite was synthesized through an in-situ oxidative polymerization technique with simultaneous dispersion of TiO2 nanoparticles. TiO2 nanoparticles were synthesized via sol-gel process. Structural characterization was accomplished by using conventional spectroscopic and imaging techniques. I-V measurement of the nanocomposites revealed that the nearly nonconducting poly(p-phenylenediamine) after structural modification exhibits conductivity of 10-6 S/cm leading to formation of wide band gap semiconducting materials.

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Synthesis and characterization of oleic acid stabilized CdTe quantum dots and their properties as luminescence quencher of a pyridine pendented rod-coil homopolymer

Kaur Manpreet, Sahu Duryodhan

Materials Science Poland

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2020

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Vol. 38, No. 4

577--583

EN

We report a facile one-step non aqueous synthesis of oleic acid stabilized cadmium telluride (CdTe) quantum dots (QDs) with an average diameter of 3 nm to 4 nm by hot injection method. The synthesized oleic acid capped QDs observed by TEM were nearly spherical. The optical properties of QDs were characterized by UV-Vis absorption spectra and photoluminescence (PL) spectra. The structures of QDs and their surface passivation were further verified using transmission electron microscope (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The quenching effect of the CdTe QD was explored by addition of CdTe nanocrystals into a solution of rod-coil homopolymer (poly[10-(6-(9,9-diethyl-7-(pyridin-4-yl)-9H-fluoren-2-yl)naphthalen-2-yloxy) decyl methacrylate]) (PFNA) having pendent pyridine. The gradual addition of quantum dots to the solution of PFNA quenched the PL spectra of PFNA. This may be used to explore the coordination ability of pyridine containing homopolymer with CdTe quantum dots.