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1

Mechanical and thermal properties of rigid PVC and graphene nanocomposites obtained by melt-mixing

Wilczewski Sławomir, Skórczewska Katarzyna, Tomaszewska Jolanta, Lewandowski Krzysztof, Şentürk Ömer Faruk

Polimery

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2024

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Vol. 69, nr 2

86--91

EN

The effect of graphene (0.01, 0.1, 0.5 and 1 wt%) on the mechanical properties and thermal stability of rigid PVC was investigated. The morphology and thermal properties were analyzed by scanning electron microscopy (SEM) and thermogravimetric thermal analysis (TGA). Additionally, tensile properties, impact strength and hardness were determined. It was found that the addition of graphene can increase the impact strength and hardness and extend the thermal stability time of PVC.

PL

Zbadano wpływ grafenu (0,01; 0,1; 0,5 i 1% mas.) na właściwości mechaniczne i stabilność termiczną twardego PVC. Strukturę i właściwości termiczne analizowano za pomocą skaningowej mikroskopii elektronowej (SEM) i termograwimetrycznej analizy termicznej (TGA). Ponadto określono właściwości mechaniczne przy rozciąganiu, udarność i twardość. Stwierdzono, że dodatek grafenu może zwiększyć udarność i twardość oraz wydłużyć czas stabilności termicznej PVC.

2

Effect of TiC and BN nanoparticles on mechanical and microstructural characteristics of Al7085 hybrid nanocomposites

Garapati Prem Kumar, Dumpala Lingaraju, Rao Y Seetha Rama

Composites Theory and Practice

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2024

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R. 24, nr 1

57--64

EN

This study regards investigations of the mechanical properties of aluminum 7085/TiC/BN hybrid metal matrix nanocomposites (HMMNCs). The ultrasonic assisted stir casting (UASC) route was used to manufacture the Al7085 HMMNCs by varying the wt.% of titanium carbide (TiC) and boron nitride (BN) (0.0, 0.5, 1.0, 1.5, and 2.0). By means of scanning electron microscopy (SEM) it was observed that the nanoparticles are evenly distributed in the nanocomposites. Additionally, the EDS and XRD results indicate that there were no signs of oxide formations, secondary phases, or impurities in the nanocomposites. The yield tensile strength (YTS), ultimate tensile strength (UTS) and microhardness of the nanocomposites improved with increases in the wt.% of TiC and BN particles up to 1.5, and thereafter decreased. The % elongation of the nanocomposites was reduced and the density of the nanocomposites improved with the addition of TiC and BN nanoparticles.

3

Zinc and graphene oxide composites as new protective coatings for oil and gas pipes

Asghar M. Sajid Ali, Amir Muhammad, Hussain Umer, Sabri Mohammed M.

Polimery

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2023

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Vol. 68, nr 7-8

378--385

EN

A method was developed to obtain a durable coating consisting of zinc and graphene oxide (Zn-GO) in order to reduce the mechanical wear and tear rate of oil and gas pipelines made of steel. Graphene oxide was obtained from graphite by wet chemical oxidation (unmodified and modified Hummers’ method) using potassium permanganate and sulfuric acid. The process was carried out at various temperatures. The steel was covered with an ultrathin layer of Zn-GO using the electrophoretic deposition method. The GO particle size (< 90 nm) was confirmed by XRD and laser analysis. For GO particles obtained by the modified Hummers’ method, a significant correlation was observed in the scratch (R2 = 0.87) and the Vickers microhardness tests (R2 = 0.93), which indicates a lower wear rate of Zn-GO-coated steel.

PL

Opracowano metodę otrzymywania trwałej powłoki składającej się z cynku i tlenku grafenu (Zn-GO) w celu zmniejszenia zużycia mechanicznego rurociągów naftowo-gazowych wykonanych ze stali. Tlenek grafenu pozyskano z grafitu metodą mokrego utleniania chemicznego (niezmodyfikowana i zmodyfikowana metoda Hummersa) z użyciem nadmanganianu potasu i kwasu siarkowego. Proces prowadzono w różnej temperaturze. Stal powlekano ultra cienką warstwą Zn-GO techniką osadzania elektroforetycznego. Metodą XRD i analizą laserową potwierdzono wielkość cząstek GO (≤ 90 nm). Dla cząstek GO otrzymanych zmodyfikowaną metoda Hummersa zaobserwowano znaczącą korelację w teście zarysowania (R2 = 0.87) i mikrotwardości Vickersa (R2 = 0.93), co świadczy o mniejszym stopniu zużycia stali pokrytej powłoką Zn-GO.

4

The use of chitosan as an effective carrier of theophylline – an anti-asthmatic drug

Aziz Noor Firas, Hussein-Al-Ali Samer Hasan, Ghareeb Mowafaq Mohammed, Nashwan Nashwan Abdallah

Polimery

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2023

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Vol. 68, nr 3

157--168

EN

In order to solve the problem of frequent drug dosing and increase its effectiveness, theophylline (THP) was deposited on chitosan nanoparticles (CSNPs). THP-CSNPs nanocomposites with the composition of 50, 75, 100 or 150 mg of chitosan (CS) and 25, 50, 75, 100 or 200 mg of tripolyphosphate (TPP) at pH 4.0, 5.0, 6.0 and 6.5 were prepared, and a constant weight of THP of 100 mg. The nanocomposites were characterized by X-ray diffraction (PXRD), field emission scanning electron microscopy (FE-SEM), and Fourier transform infrared spectroscopy (FTIR). The rate of drug release was also tested. The Minitab 18 program was used to analyze the results. The independent variables were the CS, TPP, and pH, while loading efficiency, zeta potential, and particle size were the dependent variables. The nanocomposites successfully transported and protected the drug, providing its sustained release.

PL

W celu rozwiązania problemu częstego dawkowania leku i zwiększenia jego efektywności teofilinę (THP) osadzono na nanocząstkach chitozanu (CSNPs). Przygotowano nanokompozyty THP-CSNPs o składzie 50, 75, 100 lub 150 mg chitozanu (CS) oraz 25, 50, 75, 100 lub 200 mg trójpolifosforanu (TPP) przy pH 4,0, 5,0, 6,0 i 6,5 oraz stałej masie THP wynoszącej 100 mg. Nanokompozyty charakteryzowano za pomocą dyfrakcji promieniowania rentgenowskiego (PXRD), skaningowej mikroskopii elektronowej z emisją polową (FE-SEM), spektroskopii w podczerwieni z transformacją Fouriera (FTIR). Zbadano również szybkość uwalniania leku. Do analizy wyników wykorzystano program Minitab 18. Niezależnymi zmiennymi były CS, TPP i pH, podczas gdy wydajność ładowania, potencjał zeta i wielkość cząstek były zmiennymi zależnymi. Nanokompozyty z powodzeniem transportowały i zabezpieczały lek, zapewniając jego przedłużone uwalnianie.

5

Synthesis of hydrogel nanocomposites and their application in removing dyes and impurities

Ebrahimi Rajabali, Taherkhani Mahboubeh

Polimery

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2023

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Vol. 68, nr 5

276--285

EN

Polyacrylate hydrogels containing starch, ZnSe and Fe3O4 nanoparticles were obtained. The polymerization process was carried out in an ultrasonic field. The structure (SEM, FTIR, XRD), swelling properties and the ability of hydrogels to adsorb dyes (methylene blue, methyl orange, methyl red and Eriochrome Black T) and heavy metals (Cu2+) from wastewater were investigated. Hydrogels containing AgCl nanoparticles were also obtained, which, due to their antibacterial properties, can be potentially used in medicine.

PL

Otrzymano hydrożele poliakrylanowe zawierające nanocząstki skrobi, ZnSe i Fe3O4. Proces polimeryzacji prowadzono w polu ultradźwiękowym. Zbadano strukturę (SEM, FTIR, XRD), właściwości pęczniejące oraz zdolność hydrożeli do adsorpcji barwników (błękit metylenowy, oranż metylowy, czerwień metylowa i czerń eriochromowa T) oraz metali ciężkich (Cu2+) ze ścieków. Otrzymano również hydrożele zawierające nanocząstki AgCl, które ze względu na właściwości antybakteryjne mogą znaleźć potencjale zastosowanie w medycynie.

6

Morphology and selected properties of NR/BR/CNT nanocomposites – effect of ethanol-assisted mixing

Zhang Juzheng, Gu Zheng, Meng Chao, Wang Jianfa, Sui Jinyong

Polimery

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2023

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Vol. 68, nr 5

251--258

EN

Carbon nanotubes (CNT) and ethanol-assisted mixing were used to obtain composites based on a mixture of natural rubber and butadiene rubber (NR/BR 80/20). The structure of the composites was determined by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Thermal aging tests were also carried out and the vulcanization process was characterized. SEM confirmed the homogeneous dispersion of CNTs in the polymer matrix. Improvements in tensile and tear strength as well as thermal stability were also achieved.

PL

Do otrzymywania kompozytów na bazie mieszaniny kauczuku naturalnego i butadienowego (NR/BR 80/20) zastosowano nanorurki węglowe (CNT) i mieszanie wspomagane etanolem. Strukturę kompozytów określono za pomocą spektroskopii w podczerwieni z transformacją Fouriera (FTIR) oraz skaningowej mikroskopii elektronowej (SEM). Przeprowadzono również badania starzenia termicznego oraz scharakteryzowano proces wulkanizacji. Metodą SEM potwierdzono jednorodną dyspersję CNT w osnowie polimerowej. Uzyskano również poprawę wytrzymałości na rozciąganie i rozdzieranie oraz stabilności termicznej.

7

Influence of EDM process parameters of novel Al7010/B4C/BN hybrid metal matrix nanocomposite

Dirisenapu Gopichand, Salavaravu Laxmanaraju, Dumpala Lingaraju

Composites Theory and Practice

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2023

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R. 23, nr 4

191--196

EN

In this present research work, the electrical discharge machining (EDM) characteristics of an Al7010/2%B4C/2%BN (the reinforcement particles are taken as wt.%) hybrid metal matrix nanocomposite (HMMNC) are discussed. The effect of the EDM process variables like the discharge current (I), pulse on time (Pon), pulse off time (Poff) and gap voltage (Vg) on the response characteristics like the material removal rate (MRR), tool wear rate (TWR), and surface roughness (SR) are presented. The results revealed that the MRR, TWR, and SR grew with an increase in Ip and Pon. MRR, TWR, and SR increased with a rise in Poff up to 25 μs then declined. MRR, TWR, and SR decreased with an increment in gap voltage. The highest MRR was observed for a discharge current of 8 A, Pon of 60 μs, Poff of 25 μs and Vg of 30 V. SR and TWR were the smallest at Ip of 2 A, Pon of 15 μs, Poff of 55 μs and Vg of 60 V. The scanning electron microscope (SEM) micrographs of the machined surfaces revealed voids, craters and micro cracks.

8

Study of Crystalline and Thermal Properties of Nanocomposites Based on Polyamide-6 and Modified Montmorillonite

Krasinskyi Volodymyr, Dulebova Ludmila, Gajdoš Ivan, Krasinska Oksana, Jachowicz Tomasz

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 6

88--97

EN

The main operational characteristics of polyamide-6-montmorillonite (PA6/MMT) nanocomposites, which determine their fields of application, mainly depend on the crystal structure and crystallinity of the polymer. Therefore, the study of the crystalline behavior of PA6 in such nanocomposites is of considerable scientific and practical importance. In this work, the structure, crystalline, and thermal properties of nanocomposites based on PA6 and modified MMT prepared in a formic acid solution were investigated using the methods of differential scanning calorimetry (DSC) and X-ray Diffraction (XRD). It was established that during the manufacture of PA6/MMT nanocomposites in a solution, the dominant crystal structures are the thermodynamically stable α structures of PA6. The crystallinity degree of PA6 in nanocomposites is about 1.5 times higher than that of the original PA6. It is shown that after additional thermomechanical treatment of nanocomposites on a capillary viscometer at 230°С and a load of 5 kg, the uniformity of the distribution of exfoliated MMT in the polymer matrix increases, as a result of which the crystalline structure of PA6 changes and its glass transition and melting temperatures increase. These changes in the PA6 structure also have a significant impact on the melt flow index and the softening temperature of nanocomposites.

9

The modern approach to manufacturing of carbon-rhenium nanocomposites

Dobrzańska-Danikiewicz A. D., Wolany W.

Journal of Achievements in Materials and Manufacturing Engineering

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2022

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Vol. 115, nr 2

57--63

EN

Purpose: The aim of the paper is to present the high-temperature method of producing MWCNTs-Re nanocomposites, the selection of satisfactory production conditions and the presentation of the results of microscopic and spectroscopic studies of nanocomposites produced by this method. Design/methodology/approach: Two methods of manufacturing carbon-rhenium nanocomposites were tested: ineffective chemical synthesis and high-temperature reduction using H2, which was proven successful and allowed the production of nanocomposites with the expected properties. The received nanocomposites were investigated using Transmission Electron Microscope (TEM), and Scanning Electron Microscope (SEM), as well as were subjected to spectroscopic examination. Findings: The article presents three steps of MWCNTs-Re nanocomposites fabrication using the high-temperature method, functionalization, impregnation and reduction. As part of own work, satisfactory conditions for producing those nanocomposites using a materials science and heuristic analysis were selected. Research limitations/implications: The proposed high-temperature method allows to join rhenium nanoparticles with MWCNTs permanently. It is reasonable to test in the future whether the method is also effective for other carbon nanomaterials and/or nanoparticles of other metals. Practical implications: MWCNTs-Re nanocomposites can be used as sensors of gases that are harmful to the environment. It was also confirmed that the MWCNTs-Re_4 nanocomposite has catalytic properties. Originality/value: The paper presents a modern approach to the manufacturing of MWCNTs-Re nanocomposites, which assumes the use of a high-temperature furnace to heat the material in a hydrogen atmosphere.

10

Influence of Synthesis Conditions on the Chemical Structure and Composition of ZnO Nanoparticles Composite Systems / Polymer Fibers

Calin Gabriela, Sachelarie Liliana, Olaru Niculae

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

601--606

EN

Nanostructured systems based on ZnO nanoparticles composite systems/polymer fibers have attracted a lot of attention in the last years because of their applications in multiple areas. Nanofibres based on polymers are used in many domains such as nanocatalysis, controlled release of medicines, environmental protection and so on. This work show the synthesis of cellulose acetate butyrate (CAB) nanofiber useful as substrates for growing ZnO nanocrystals and that ZnO is an unorganic metal oxide nanoparticle used to improve the piezoelectric properties of the polymer. The piezoelectric properties of ZnO-doped polymeric was investigated with atomic force microscopy and measurements were performed, in contact technique, in piezoelectric response mode (PFM). In order to analyze the structural and textural features, the obtained materials were characterized using advanced physical-chemical techniques such as X-ray diffraction (XRD), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM). The XRD patterns show the characteristic reflections of ZnO with a hexagonal type wurtzit structure and the broad peaks of the polymer. The SEM images reveal the presence of ZnO nanoparticles on top of the polymer nanofibres. In most ZnO-based nanocomposites their morphology is uncontrolled (agglomerated granules), but in ase of using cellulose acetobutyrate this becomes controlled by observing through flower-like structures SEM and AFM) The study of the functional properties of ZnO/polymer fiber composite systems showed that they have piezoelectric properties which give them the characteristics of smart material with possible sensor and actuator applications. Recent literature reports that the synthesis and characterization of ZnO-polymer nanocomposites are more flexible materials for various applications.

11

Synergistic effect of ball milling time and nano‑sized Y2O3 addition on hardening of Cu‑based nanocomposites

Salur Emin

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 2

art. no. e103, 1--18

EN

A fruitful combination of powder metallurgy and the mechanical alloying route is one of the most promising process for producing advanced Cu-based nanocomposites. In this study, three different material systems, namely, pure copper (Cu), 5 wt% Cr reinforced Cu matrix composites, and 1 wt% Y2O3 reinforced Cu-Cr matrix nan-composites were synthesized by ball milling method at different milling times. The influence of different ball milling times (0.5, 2, and 4 h) and different types of reinforcements (Cr and Y2O3) on the powder and sintered parts properties were thoroughly analyzed with a holistic approach. The milled powders were then consolidated using a cold press followed by a liquid phase sintering process. Results revealed that the Cr and Y2O3 particles were fractionally dispersed and imbedded in the ductile Cu matrix with respect to increasing milling time. Milling for 4 h of Cu-Cr-2O3 powders produced the lowest level of particle size (28 μm) with reduced and flattened and uniformly distributed reinforcement phases due to intense plastic deformation induced shearing effect and dominant powder-ball-jar collisions. Besides, the ball milling process of the same powders concluded a decrement of crystallite size to 35 nm in concomitant with an increase of lattice strain and dislocation density ⁓ % 0.3 and 0.8×1015 line/m2 , respectively. Brinell hardness of the sample produced by these powders increased from 39 to 95 HB. A ⁓%145 striking increase of hardness could be attributed to the strong hindrance of high-dense dislocations triggered by several concurrent strengthening mechanisms. Nevertheless, relative density results of sintered samples revealed that the addition of Cr and Y2O3 along with increasing milling time deteriorated the density due to the higher hardness and brittleness of milled powders and accompanying worsened compressibility and sinterability. The source of noticed differences between hardness and density results were discussed within the process-structure-performance framework.

12

Combined axial and lateral stability behavior of random checkerboard reinforced cylindrical microshells via a couple stress-based moving Kriging meshfree model

Liu Hongwei, Safaei Babak, Sahmani Saeid

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 1

art. no. e15, 2022

EN

In this investigation, a size-dependent numerical solution methodology is devised to analyze nonlinear buckling and postbuckling of cylindrical microsized shells made of checkerboard randomly reinforced nanocomposites subjected to a combination of axial and lateral compressions. To accomplish this purpose, the modified couple stress elasticity continuum is formulated within the third-order shear flexible shell model. Using a probabilistic-based homogenization plan in conjunction with the Monte-Carlo simulation, the effective mechanical parameters of the randomly reinforced nanocomposites are captured. The established size-dependent problem is then numerically solved via using the moving Kriging meshfree technique having the ability to enforce the required boundary conditions straightly at the associated nodes without using any type of penalty technique. By tracing the nonlinear stability paths, it is revealed that for the both axial dominated and lateral dominated loading cases, the stiffening feature related to the rotation gradient tensor causes that the microshell endures higher shortening before the buckling phenomenon occurs. In addition, it is found that by increasing the length to width ratio of graphene nanofillers, the effect of combination of axial or lateral load increases a bit.

13

The impact of reduced graphene oxide on the properties of polyamide 6

Sabet Maziyar, Hosseini Seyednooroldin

Polimery

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2021

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T. 66, nr 4

224--233

EN

Polyamide 6 (PA6) nanocomposites with electric and thermal conductive properties were formulated via melt processing of PA6 and different inclusion of reduced graphene oxide (RGO). These nanocomposites showed that the small percolation threshold and the perfect formation of conductive link form with 0.5 wt % and ~3.0 wt % of RGO, respectively. Examination of crystallization confirmed that RGO enabled the crystallization of PA6 structure mostly through speeding up the formation of crystal nucleus, reaching the biggest and the smallest of crystal grain extent with RGO inclusion up to 2.0 wt % what enabled the generation of the most unflawed crystalline matrix. Dynamic rheological testing results indicated the frequency-independence of G’ and abruptly decrease phase angle at the small-frequency area via RGO content of 2.0 wt % specifies the alteration state from liquid-state to solid-state rheological performance, and validates the development of percolation link structure with RGO in the function of a crosslinking factor. The progress of fire-retardant characteristics of PA6 was attained due to the inclusion of RGO in the PA6 structure. Morphological research showed that RGO was spread consistently in the PA6 structure. The outcomes of cone calorimetry showed that the flame-retardant characteristics of PA6 were promoted with the addition of RGO in the PA6 structure. These tests show substantial capacity for the bulk manufacture of electric conductive polymer/RGO nanocomposites.

PL

Na bazie poliamidu 6 (PA6), przetwarzanego w stanie stopionym z dodatkiem różnej ilości zredukowanego tlenku grafenu (RGO), otrzymano nanokompozyty charakteryzujące się przewodnictwem elektrycznym i termicznym. Nanokompozyty o zawartości 0,5% mas. RGO wykazywały niski próg perkolacji, a próbki o zawartości ~3% mas. GRO – doskonale utworzoną fazę przewodzącą. Badania potwierdziły, że dodatek do PA6 2,0% mas. RGO umożliwił krystalizację struktury PA6, głównie w wyniku przyspieszenia tworzenia się jądra krystalicznego, i osiągnięcie zarówno największych, jak i najmniejszych wymiarów ziaren krystalicznych, co pozwoliło na utworzenie maksymalnie bezbłędnej matrycy krystalicznej. Wyniki dynamicznych testów reologicznych wskazały na niezależność modułu elastyczności (G’) od częstotliwości i na gwałtowne zmniejszenie kąta fazowego w obszarze małej częstotliwości w wypadku próbek nanokompozytów o zawartości RGO 2% mas., typowe dla zmian właściwości reologicznych przy przejściu ze stanu ciekłego do stanu stałego i potwierdzające rozwój struktury połączeń perkolacyjnych PA6 z RGO, pełniącym funkcję czynnika sieciującego. Włączenie do struktury PA6 zredukowanego tlenku grafenu przyczyniło się do polepszenia właściwości ogniochronnych otrzymanych nanokompozytów. Ocena morfologii próbek nanokompozytów wykazała, że cząstki RGO rozproszyły się równomiernie w strukturze PA6. Na podstawie wyników kalorymetrii stożkowej stwierdzono uniepalniający wpływ dodatku RGO do PA6. Wykazano, że opisaną metodą można otrzymywać na skalę masową przewodzące prąd nanokompozyty PA6/RGO.

14

Nanokompozyty na osnowie polipirolu w ochronie metali przed korozją – przegląd literatury

Zaręba Aleksandra

Polimery

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2021

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T. 66, nr 3

169--174

PL

Korozji, jako procesu korzystnego termodynamicznie, nie można zatrzymać, ponieważ metale występują naturalnie w postaci rud tlenkowych lub soli metali. Dla gospodarki jest to niestety proces kapitałochłonny i niepożądany, jednak z zastosowaniem odpowiednich strategii działania można ograniczyć jego skalę. Niniejszy przegląd literatury, głównie z lat 2018–2020, skupia się na powłokach kompozytowych opartych na polimerze przewodzącym – polipirolu (PPy), wybranych tlenkach metali oraz, ewentualnie, domieszkach surfaktantów i innych związków. Celem pracy jest wykazanie roli polipirolu – polimeru przewodzącego, a przy tym ekologicznego, w ochronie konstrukcji przed korozją metali.

EN

Corrosion cannot be stopped due to its thermodynamically favorable character, since metals occur naturally in the form of oxide ores or metal salts. It is an adverse and capital-intensive process for the economy. However, it can be alleviated by adopting various strategies. This review of the literature, mainly from 2018–2020, focuses on composite coatings based on a conductive polymer – polypyrrole (PPy) and on some metal oxides with the possible use of surfactant admixtures and other compounds. The aim of the study is to emphasize the role of polypyrrole – a conductive and ecological polymer – in the protection of structures against metal corrosion.

15

Effects of carbon nanotubes and graphene on the structure and properties of natural rubber

Sui Jinyong, Gu Zheng, Zhang Xiaoyi, Li Zhenxu, Song Lining, Yang Lina, Wang Ning

Polimery

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2021

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T. 66, nr 4

217--223

EN

Natural rubber (NR) is an important strategic material for national defense industry. It is also used in the food industry and medicine. However, due to the unsaturated double bond, its aging resistance, mechanical properties and solvent resistance are very poor. In order to improve these properties, carbon nanotubes (CNTs) and reduced graphene oxide (rGO) were used, added at 1 : 1 ratio. The NR/CNTs/rGO nanocomposites were obtained by mechanical mixing aft er adding 1, 2, 3 and 4 phr of fi ller. The infl uence of the fi ller content on the structure (TEM), vulcanization properties, abrasion and solvent resistance, mechanical properties, dynamic mechanical properties (DMA) and thermal properties (TGA) of nanocomposites was investigated. Increasing the content of CNTs/rGO increased the crosslinking density of the composites. TEM studies showed that CNTs and graphene sheets were evenly dispersed throughout the NR matrix. They also had good compatibility with the rubber matrix. The addition of CNTs and graphene increased the abrasion and solvent resistance as well as improved the mechanical properties. TGA analysis showed that the nanocomposites had excellent thermal stability. The best properties were obtained with the CNTs/rGO content of 2 phr.

PL

Kauczuk naturalny (NR) stanowi ważny materiał strategiczny dla przemysłu obronnego. Znajduje również zastosowanie w przemyśle spożywczym i medycynie. Jednak obecność w cząsteczce nienasyconych podwójnych wiązań powoduje osłabienie jego odporności na starzenie, pogorszenie wytrzymałości mechanicznej i odporności na działanie rozpuszczalników. W celu poprawy tych właściwości do kauczuku naturalnego wprowadzono nanorurki węglowe (CNTs) i zredukowany tlenek grafenu (rGO), dodawane w stosunku 1 : 1. Nanokompozyty NR/CNTs/rGO otrzymywano metodą mechanicznego mieszania NR z 1, 2, 3 lub 4 phr napełniacza (CNTs/rGO). Zbadano wpływ zawartości dodatku na strukturę (TEM), właściwości wulkanizacyjne, właściwości mechaniczne, odporność na ścieranie i działanie rozpuszczalnika, dynamiczne właściwości mechaniczne (DMA) i właściwości termiczne (TGA) wytworzonych kompozytów. Zwiększenie udziału CNTs/rGO powodowało zwiększenie gęstości usieciowania kompozytów. Z badań TEM wynika, że cząstki CNTs i grafenu były równomiernie rozproszone w osnowie NR i wykazywały dobrą kompatybilność z kauczukiem naturalnym. Dodatek CNT i grafenu zwiększył odporność na ścieranie i działanie rozpuszczalników oraz poprawił właściwości mechaniczne naturalnego kauczuku. Na podstawie analizy TGA stwierdzono, że nanokompozyty charakteryzowały się doskonałą stabilnością termiczną. Najlepszymi właściwościami użytkowymi odznaczały się kompozyty NR zawierające 2 phr CNTs/rGO.

16

Radiolytic synthesis of gold nanoparticles in HEMA-based hydrogels : potentialities for imaging nanocomposites

Dziarabina Katsiaryna, Pinaeva Uliana, Kadłubowski Sławomir, Ulański Piotr, Coqueret Xavier

Nukleonika

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2021

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Vol. 66, No. 4

165--177

EN

This article reports on the radiolytic synthesis of nanocomposites containing gold nanoparticles (AuNPs) within two types of hydrogels based on 2-hydroxyethyl methacrylate (HEMA): (i) plain networks with various contents in ethylene glycol dimethacrylate (EGDMA), as a cross-linker and (ii) stimuli-responsive (SR) networks prepared from these monomers copolymerized with [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MADQUAT) to confer pH-switchable swelling. Hydrogels were prepared by photopolymerization with well-defi ned composition and a high degree of monomer conversion using two experimental procedures, as xerogels or in aqueous solution. Besides MADQUAT, acrylic acid (AA) or N-isopropylacrylamide have been tested as copolymers, yielding pH- or temperature-sensitive hydrogels, respectively. Isothermal swelling in water was affected by monomer composition. Electron beam (EB) irradiation at doses up to 100 kGy of poly(HEMA) xerogels and water-swollen networks prepared with 0.5 wt% of EGDMA had a moderate impact on swelling characteristics and thermomechanical properties of the plain materials, whereas small amounts of extractables were formed. Poly(HEMA)-based nanocomposites containing AuNPs were successfully obtained by EB irradiation of samples swollen by aqueous solutions of Au(III). The effects of dose and cross-linking density on the formation of AuNPs were monitored by UV-visible spectroscopy. Irradiation at well-defined temperatures of the Au(III)-loaded SR hydrogels induced the formation of nanoparticles with size-dependent features, whereas the efficiency of Au(III) reduction at 10 kGy was not significantly affected by the network structure. EB-induced reduction of Au(III) in poly(HEMA) hydrogels using a lead mask to generate well-defined patterns yielded coloured and long-lasting images in the zones where the nanocomposite was formed.

17

Badanie wpływu rodzaju nanocząstek na właściwości adhezyjne poliestrowej żywicy nienasyconej modyfikowanej poliuretanem

Suroń Patryk, Białkowska Anita, Bakar Mohamed

Modelowanie Inżynierskie

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2021

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T. 42, nr 73

63--68

PL

W pracy przedstawiono wpływ rodzaju nanocząstek na właściwości adhezyjne nienasyconej żywicy poliestrowej modyfikowanej poliuretanem. Otrzymano kompozycje żywicy poliestrowej z udziałem trzech różnych rodzajów nanocząstek (NanoBent ZS1, Bentone 34 i Cloisite 5) i z różną ich ilością w próbkach (1%, 2%, 3%).Następnie oznaczono wytrzymałość na ścinanie i odrywanie kompozytów. Na podstawie uzyskanych wyników wytypowano ilość nanonapełniacza stosowanego do modyfikacji żywicy poliestrowej w kompozycjach hybrydowych. Trójskładnikowe kompozycje różniły się zawartością poliuretanu (2,5%, 5%, 7,5% i 10%)oraz rodzajem i wytypowaną ilością użytego nanonapełniacza. Stwierdzono, że największą poprawę oznaczanych właściwości odnotowano w próbkach hybrydowych zawierających 2% Bentone 34 i 2,5% poliuretanu oraz kompozycji zawierającej 1% Cloisite 5 i 2,5% poliuretanu.

EN

The work presents the effect of nanoparticles on the adhesive properties of unsaturated polyester resin modified with polyurethane. Compositions with three different nanoparticles (NanoBent ZS1, Bentone 34 and Cloisite 5) and different amounts (1%, 2%, 3%) were prepared and tested for their tensile and shear adhesive strength. Based on the obtained results, appropriate hybrid composites based on different polyurethane content (2.5%, 5%, 7.5% and 10%) were prepared. It was shown, that he highest improvement of adhesive properties was observed for a hybrid composite containing 2% Bentone 34 and 2.5% polyurethane as well as composite based on 1% Cloisite 5 and 2.5% polyurethane.

18

Conductive polymer nanocomposites for medical applications

Kuczkowska Justyna, Długoń Elżbieta, Bezkosty Patryk, Nizioł Jacek, Błażewicz Marta, Sitarz Maciej

Engineering of Biomaterials

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2021

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Vol. 24, no. 163

118

19

Nanocellulose as a new sustainable material for various applications: a review

Fahma F., Febiyanti I., Lisdayana N., Arnata I.W., Sartika D.

Archives of Materials Science and Engineering

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2021

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Vol. 109, nr 2

49--64

EN

Purpose: This paper presents a comprehensive review of nanocellulose and its application in several applications, including composites, biomedical, and food packaging fields. Design/methodology/approach: General explanations about cellulose and nanocellulose have been described. Different types of nanocellulose (cellulose nanofibers, cellulose nanocrystals, bacterial nanocellulose) as well as their isolation processes (mechanical process, chemical process) have been reviewed. Several surface modifications have been explained to improve the dispersion of nanocellulose in non-polar polymers. The possible utilization of nanocellulose in composites, biomedical, and food packaging fields have also been analysed. Findings: This review presents three application fields at once, namely composites, biomedical, and food packaging fields. In the composite field, nanocellulose can be used as a reinforcing agent which increases the mehcnical properties such as tensile strength and toughness, and thermal stability of the final composites. In the biomedical field, nanocellulose is reinforced into hydrogel or composites which will be produced as tissue scaffolding, wound dressing, etc. It is found that the addition of nanocellulose can extend and control the drug release. While in the packaging field, nanocellulose is added into a biopolymer to improve the barrier properties and decrease the water and oxygen vapor transmission rates. Research limitations/implications: Nanocellulose has a hydrophilic nature, thus making it agglomerated and difficult to disperse in most non-polar polymers. Therefore, certain surface modification of nanocellulose are required prior to the preparation of composites or hydrogels. Practical implications: Further research regarding the toxicity of nanocellulose needs to be investigated, especially when applying it in the biomedical and food packaging fields. Originality/value: This review presents three application fields at once, namely composites, biomedical, and food packaging fields.

20

Hybrydowe nanokompozyty typu metal-białko serwatkowe

Rodzik Agnieszka, Pomastowski Paweł, Railean-Plugaru Viorica, Buszewski Bogusław

Analityka : nauka i praktyka

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2021

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nr 2

4--12

PL

Obok całej gamy związków nieorganicznych i organicznych ważną i interesującą grupę związków biologicznie aktywnych stanowią białka serwatkowe. Mają one zdolność do oddziaływania z jonami metali. Aby zrozumieć zjawiska oddziaływań metal-białko, ważne jest opracowanie i wdrożenie nowych, innowacyjnych metod analitycznych, połączonych z badaniami zmian aktywności biologicznej oraz analizą wpływu tych oddziaływań.