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1

Preparation of nano membranes with triethylenetetramine dihydrochloride (TETA-DH) and multiwalled carbon nanotubes (MWCNT) for seawater desalination

Alghamdi Ahmed

Polish Journal of Chemical Technology

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2024

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Vol. 26, nr 2

1--7

EN

Seawater Desalination uses hydrophobic membranes. Many techniques have been developed to improve membrane hydrophobicity by depositing particles on the membrane surface. In this study, a nanocomposite membrane utilizing Triethylenetetramine (TETA) is suggested. The membrane incorporates Multiwalled Carbon Nanotubes (MWCNT) in conjunction with Triethylenetetramine Dihydrochloride (TETA-DH). In water bath, different percentages of TETA-DH films are formed. Electro-spin fabrication of MWCNTs using TETA-DH yields smooth, low-pore membranes. Membranes and their characteristics are identified by contact angle, layer thickness, and conductivity measurements. Membrane performance is examined for heat flux and salt rejection. Compared to commercial membranes, the proposed membrane exhibits superior antifouling and anti-wetting features. The membrane exhibited permeation and rejection ratio of 46 Kg m2 h–1 and 99.99% respectively which is superior as compared with other membranes. The hydrophilic Surface Modifying Macromolecules percentage (LSMM%) is evaluated because it depends on average pore size, hydrophobicity, surface porosity, and shape. The tests demonstrate the excellent performance of the proposed membrane for controlling membrane fouling.

2

The effectiveness of impregnation of building materials of cellulose origin and its impact on selected properties

Niewiadomski Paweł, Karolak Anna, Oleksiak Marta, Chowaniec-Michalak Agnieszka

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2024

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Vol. 72, nr 2

art. no. e148876

EN

One of the biggest challenges facing a designer of paper structures is its low resistance to moisture and water. Paper is a hydrophilic material that absorbs moisture from the outside. This causes the hydrogen bonds between the cellulose molecules to loosen and as a result a rapid decrease in strength parameters. In order to be able to use paper as a construction material, there is a need to select and evaluate the effectiveness of the appropriate impregnant, as well as to know its impact on the mechanical properties of the impregnated paper. The paper analyzes the effect of the use of various impregnations, including wood oil, yacht lacquer, and fire-retardant agent impregnation, on the tensile strength of several types of cellulose-derived materials, e.g. corrugated board, solid board, paper cores, and honeycomb board. The effectiveness of the impregnation was also assessed using the method of measuring the contact angle of the reference and impregnated surfaces.

3

Application of Drop Shape Analyzer to measure the wettability of cotton woven fabrics

Kamińska Dominika, Matusiak Małgorzata, Čorak Ivana, Tarbuk Anita

Technologia i Jakość Wyrobów

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2023

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R. 68

80--92

EN

The method of measuring the contact angle, applied in an assessment of material hydrophobicity, is well known and suitable for evaluating the solid substrates with smooth geometry. For these substrates data evaluation is quite straightforward. In the case of textile substrates, the interpretation of the contact angle value is difficult, mainly due to two properties of the substrate - the roughness and an ability of the substrate to absorb the liquid drops. In the presented work 6 cotton fabrics with different weaves (plain, twill 3/1 S, twill 2/2 S, rep 2/2 (2), rep 1/1 (0,1,0), hopsack 2/2 (0,2,0)) were tested. Measurements were performed using the Drop Shape Analyzer (DSA).

PL

Metoda pomiaru kąta zwilżania, stosowana w ocenie hydrofobowości materiałów, jest dobrze znana i nadaje się do oceny podłoży stałych o gładkiej geometrii. Dla tych podłoży ocena danych jest stosunkowo prosta. W przypadku materiałów włókienniczych interpretacja wartości kąta zwilżania jest utrudniona, głównie ze względu na dwie właściwości podłoża – chropowatość oraz zdolność podłoża do zasysania kropli cieczy. W ramach niniejszej pracy badaniom poddano 6 tkanin bawełnianych o różnych splotach (płócienny, skośny 3/1 S, skośny 2/2 S, ryps podłużny 2/2 (2), ryps poprzeczny 1/1 (0,1,0) oraz panama 2/2 (0,2,0)). Pomiary zostały przeprowadzone przy użyciu przyrządu Drop Shape Analyzer (DSA).

4

Analysis of the effect of assembly joints technology on the strength of adhesive joints of poly(methyl methacrylate) (pmma) used in advertising elements

Rudawska Anna, Penkała Piotr, Miszczuk Bartosz, Stančeková Dana

Technologia i Automatyzacja Montażu

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2023

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nr 2

3--10

EN

The aim of the article was to present issues related to the influence of the assembly joints technology (the type of adhesive material and the adhesive application) on the strength of the adhesive joints of poly(methyl methacrylate) (PMMA) used in the production of advertising elements. Angular adhesive joints, which are one of the types of joints made in the construction of advertising elements, were used in the study. The bonded material was poly(methyl methacrylate) (PMMA) of 8 mm thick. Two types of adhesives were used to make the adhesive joints: one-component solvent-based adhesives and methylene chloride as a solvent. Experimental tests determined the wettability of the surface of the adherends (with and without a protective coating) and the work of adhesion based on the measurement of the contact angle, as well as the strength of adhesive joints in accordance with the ISO 4578 standard. Based on the results of strength tests, it can be seen that the use of a solvent allows for obtaining equally strong joints as with the use of solvent-based adhesives. The purposefulness of using coatings protecting not only against dirt or mechanical damage in the form of scratches was also confirmed, but also the possibility of increasing (security) adhesive properties, defined in this case by wettability.

PL

Celem artykułu było przedstawienie zagadnień związanych z wpływem technologii połączeń montażowych (rodzaju materiału klejącego i sposobu aplikacji kleju) na wytrzymałość połączeń klejowych z poli(metakrylanu metylu) (PMMA) stosowanych w produkcji elementów reklamowych. W badaniach wykorzystano połączenia klejowe kątowe, które są jednym z rodzajów połączeń wykonywanych w konstrukcji elementów reklamowych. Łączonym materiałem był poli(metakrylan metylu) (PMMA) o grubości 8 mm. Do wykonania połączeń klejowych zastosowano dwa rodzaje jednoskładnikowych klejów rozpuszczalnikowych oraz chlorek metylenu, jako rozpuszczalnik. W badaniach doświadczalnych określono zwilżalność powierzchni klejonych elementów (z powłoką ochronną i bez) oraz pracę adhezyjną na podstawie pomiaru kąta zwilżania, a także wytrzymałość połączeń klejowych zgodnie z normą ISO 4578. Na podstawie wyników badań wytrzymałościowych można stwierdzić, że zastosowanie rozpuszczalnika pozwala na uzyskanie połączeń równie wytrzymałych, jak przy zastosowaniu klejów rozpuszczalnikowych. Potwierdzono również celowość stosowania powłok zabezpieczających nie tylko przed zabrudzeniami czy uszkodzeniami mechanicznymi w postaci zarysowań, ale także w celu zwiększenia (zabezpieczenia) właściwości adhezyjnych, określanych w tym przypadku przez zwilżalność.

5

Modification of Concrete Surface with Higher Fatty Acids

Barnat-Hunek Danuta, Andrzejuk Wojciech, Szafraniec Małgorzata, Kachel Magdalena, Hunek Robert

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 2

307--321

EN

The research presented in the paper concerns the production of innovative hydrophobizing agents and demonstration their effectiveness on a concrete surface. The starting materials are based on natural oils, water‒soluble silanes and siloxanes, and/or tap water. Aqueous preparations are characterized by properties which reduce the impact of volatile organic compounds (VOCs) on the environment, as they consist only of biodegradable components. Studies have shown that the higher fatty acids from vegetable oils and derived from the glycerin phase can be used as a component of concrete hydrophobizing agents, meeting the standard requirements for such agents. Analysis of the use of vegetable oil as a base compound for the production of industrial agents provides at least 95% confidence in its biodegradability. The reference concrete after the frost resistance test showed a weight loss of 1.8%. In the case of hydrophobization, the weight loss was 33.3 to 72% less than the reference samples. In the case of concrete hydrophobized with the glycerin agents, the salt crystallization occurred inside the structure of the material without causing any damage, with the reference concrete showing a weight loss of 0.8%.

6

Multiscale water drop contact angles at selected silica surfaces

Zhang Chen, Wang Xuming, Li Lixia, Jin Jiaqi, Polson Randy, Miller Jan D.

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 5

art. no. 152154

EN

In this study, multiscale advancing contact angles for glycerol/water drops at silica surfaces are reported for millidrops, submicron-drops, and nanodrops. Selected silica surfaces were muscovite, silicon, and talc. The contact angles for millidrops (1–2 mm) were determined by the traditional sessile drop technique. For submicron-drops (0.1–1.0 μm), a hollow tip Atomic Force Microscope (AFM) procedure was used. The contact angles for nanodrops (~7 nm) were examined from Molecular Dynamics (MD) simulation. The results were compared to evaluate the effect of drop size on the contact angle. In the case of the hydrophobic talc surface, the 75° advancing contact angle did not vary significantly with drop size. For the hydrophilic muscovite surface, the water drop wet the surface and an advancing contact angle of about 10° was found for the millidrops and submicron-drops. However, for the MD simulated nanodrops, attachment and spreading of the ~7 nm drop created a 2D film of molecular dimensions, the contact angle of which was difficult to define and varied from 0° to 17°. Perhaps of equal interest from the MD simulation results was that the spreading of the glycerol/water nanodrop at the muscovite surface resulted in crystallographic directional transport of water molecules to the extremities of the 2D film. Such separation and segregation left the center of the film with an increased concentration of glycerol. Based on these results, the line tension, which has been found in other investigations to account for contact angle decrease with a decrease in drop size, does not seem to be a significant factor in this study.

7

Electrokinetic and surface properties of some methacrylate-based copolymers

Ersoy Bahri, Çiftçi Hakan, Evcin Atilla, Merdivenci Yılmaz

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 5

art. no. 152162

EN

In this study, some electrokinetic and surface properties of MBAOM-GMA copolymers synthesized from 2-[(methoxy-1,3-benzothiazole-2-yl) amino]-2oxoethyl methacrylate (MBAOM) and glycidyl methacrylate (GMA) monomers were investigated. Accordingly, (i) pH-dependent zeta (ζ) potential changes of the copolymers were investigated under a constant ionic strength (in 1.10-3mol/dm3 NaCl) and the corresponding isoelectric points (iep) were determined, (ii) zeta potential changes depending on the salt concentration in the presence of mono-, di- and tri-valent metal salts were examined, (iii) contact angles (θ) of the copolymers with water were measured and their wetting behavior was assessed, and (iv) surface free energies (SFE) of the copolymers were determined by Acid-Base approach using Van Oss-Chaudhury-Good method. The compositions of the copolymers were 77% MBAOM - 23% GMA, 45% MBAOM - 55% GMA, and 19% MBAOM - 81% GMA. FeCl3, CaCl2, and KCl salts were used for the salt solutions for the zeta potential measurements. As a result, (i) it was determined that the chemical structure of methacrylate copolymers showed a decisive effect on both electrokinetic and surface properties, (ii) the hydrophobic character of copolymer increased with the increase of the GMA ratio, and correspondingly, the SFE decreased, and (iii) the iep of the copolymers varied between pH 3.1-3.7 depending on composition.

8

Control of glass surface wettability via esterification with n-alkyl alcohols

Kruszelnicki Mateusz, Polowczyk Izabela, Kowalczuk Przemyslaw B.

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 2

art. no. 145147

EN

Surface wettability plays an essential role in many processes and materials applications. It depends mainly on the surface roughness and chemical composition, thus through a controlled modification of these parameters, the wettability can be restrained. Glass is an inorganic solid material, composed mainly of amorphous silica, which surface, due to the presence of reactive hydroxyl groups, can be quite easily chemically modified. This feature can be used to control the wettability of glass by reaction with organic compounds. In this study, the esterification of glass silanol groups with n-alkyl alcohols (Cn/H2n+1/OH, n=3, 4, 6, 8, 10) was employed to modify its wettability. The effect of such modification on the physicochemical properties of glass surface was comprehensively investigated and characterised by the water contact angle, surface free energy, zeta potential, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) measurements. We demonstrate that the wettability of the esterified glass surface is strongly dependent on both the chain length of used alcohol and modification time. The alcohol molecule binds to the glass surface through a Si-O-C bond, leading to the formation of a monolayer that does not significantly affect the surface morphology and zeta potential. Conducted studies provided a broader view of the influence of this technique for modifying surface wettability on its physicochemical properties.

9

Relative wettability measurement of porous diffuser and its impact on the generated bubble size

Al-Yaqoobi Atheer M.G., Zimmerman William B.

Chemical and Process Engineering

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2022

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Vol. 43, nr 1

45-–55

EN

Controlling the bubble size is a major concern in enhancing transport performance in gas-liquid systems. The role of wettability of diffuser surface on bubble size is the subject of the current work. The study inspects the contact angle of a set of liquids on HP ceramic diffusers using the Washburn method. The results demonstrate that organic liquids like toluene, methanol–water (1:1 v/v), ethanol– water (1:1 v/v) and decane have small contact angles of 12.9, 37.5, 24.4 and 22.5 respectively. Water has a lower wettability than the organic compounds where the contact angle was about 67.4. The effect of wettability of the bubble size is investigated by measuring the size of air bubble produced using the same diffuser material. The results of bubble size measurement demonstrates that with liquids of small contact angle, i.e. good wetting properties, small bubble sizes are produced in comparison with liquids with a higher contact angle. The study demonstrates the viability of Washburn method in characterization of wettability of porous diffuser, which was verified by measuring the bubble size produced. A high reduction in bubble size can be obtained by a carefully chosen diffuser material that provides better wettability.

10

Wpływ działania plazmy niskotemperaturowej na zmiany zwilżalności wybranych polimerów

Hołysz Lucyna, Kamela (Rymuszka) Diana, Terpiłowski Konrad, Chibowski Emil

Wiadomości Chemiczne

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2021

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[Z] 75, 9-10

1270--1295

EN

The effects of air, oxygen and argon plasma treatment on wetting and energetic properties of polymers: polymethylmethacrylate (PMMA), polyetheretherketone (PEEK), polyoxymethylene (POM), polyamide (PA6G), polycarbonate (PC) and polypropylene (PP) were studied. The changes in surface properties of PMMA, PEEK, POM, PA6G polymers after the air plasma treatment, and PP and PC polymers after the Ar or O2 plasma treatment were determined via the measurement of advancing and receding contact angles of three liquids having different polarity, i.e. water, formamide and diiodomethane. Having the determined contact angles the surface free energy and its components of the polymers were calculated using three different theoretical approaches, namely: acid-base Lifsthitz-van der Waals (LWAB), contact angle hysteresis (CAH) and Owens and Wendt (O-W). The effects of plasma treatment were further determined by calculations of the adhesion work and work of spreading of water on modified polymer and compared to values calculated for the unmodified surfaces. Then for the PEEK and POM modified with the air plasma, their surface wettability was determined after 14 days from the exposure to the plasma. It was found that plasma treatment caused better wettability what reflected in a decreased contact angles measured on the modified polymer surfaces. The greatest changes appeared for polar liquids, i.e. water and formamide. It pointed to an increased the surface hydrophilicity after the plasma treatment. The changes correlated also with the increased polar interactions due to appearance polar groups on the surface. For the studied polymer surfaces, generally the dispersive interactions practically did not change, regardless the treatment time and plasma type. The total surface free energy values calculated for the polymers from three different approaches to interfacial interactions are similar. However, the energy values are apparent because they depend s upon the kind of liquid used for the contact angles measurement. Irrespectively of the plasma type, for all polymers an increase of the adhesion work of water in reference to the unmodified surfaces was observed. The most appropriate time to improve the adhesion between the polymer surface and liquid was found to be 25 or 60 s. However, the effects of plasma treatment are not permanent. With the storage time the contact angles have increased. This can be due to the structure reorganization within a few nm thick the surface layer.

11

Characteristic of polypropylene nanocomposite material reinforcement with hydroxyapatite for bone replacement

Obaid M. N., Sabr O. H., Hussein A. A.

Journal of Achievements in Materials and Manufacturing Engineering

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2021

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Vol. 104, nr 1

21--30

EN

Purpose: Human bone suffered some degeneration due to age and accidents; therefore, there are many interests in the prepared synthetic bone with properties nearer to natural bone. The present study prepared a nanocomposite of polypropylene reinforced with different weight fraction of Nano hydroxyapatite (HAp) to be used as a bone replacement with good biological properties that enhanced the growth of osteoplastic cells and enhance the prevention of clots and coagulates creation. Design/methodology/approach: Nanocomposite from polypropylene reinforced with different weight fraction of Hydroxyapatite (HAp) (1,2 and 3) % prepared by first dispersion Nano hydroxyapatite insolvent and then mixing with a pellet of polypropylene by the twin-screw extrusion process, the current research study the surface properties ( atomic force microscopy (AFM), contact angle test) Moreover, it studied the characteristics of prepared nanocomposite materials (Differential Scanning Calorimetry (DSC), Field Emission-Scanning Electron Microscopy (FE-SEM) and Fourier Transform Infrared (FTIR)). Findings: The AFM results show the surface roughness decreased with increasing content of HAp, which diminished the chance of creation clots and coagulates on it. The contact angle results referred to polypropylene behaviour transformed from hydrophobic to hydrophilic with addition HAp that permission to grow the osteoplastic cell on it, so the healing process is accelerated. Moreover, the FE-SEM images revealed uniform distribution and good bonding between polypropylene and Hydroxyapatite. The thermal properties were measured by the DSC test showed the melting temperature, and the enthalpy of melting (indicated to increase the crystalline structure per cent) are increased with increasing the percentage of Hydroxyapatite. Research limitations/implications: This research studied the characteristics of nanocomposite materials prepared by three steps (dispersion by ultrasonic device, manually mixed and melting and mixing by twin extruder) which can be used as a bone replacement. However, the main limitation was the uniform distribution of nano-hydroxyapatite within the matrix. In a further study, the cytotoxic test can be tested to study the effect of prepared nanocomposite on living cells’ growth. Practical implications: The interest object is how to connect among different properties to prepared bone replacement with good properties and biocompatibility that made able to stimulate the growth and healing process. Originality/value: The nano-hydroxyapatite is a biomaterial that has a composition similar to the natural mineral phase of the bone and does not have any negative effect, which enhanced the growth of osteoplastic cells and decreased the clots and coagulates creation; therefore, nano-hydroxyapatite is used to decrease the surface roughness which decreased the chance of coagulation creation and to enhance the hydrophilic properties.

12

Effects of different additives in a waterborne polyacrylate coating on selected surface properties of heat-treated finished wood

Nowrouzi Zahra, Mohebby Behbood, Ebrahimi Morteza, Petrič Marko

Drewno : prace naukowe, doniesienia, komunikaty

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2021

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vol. 64, nr 208

63--78

EN

Color changes of thermally modified timber due to different formulations of polyacrylate coating were studied before and after the application of the coatings. Olive leaf extract as a natural antioxidant-bearing additive was added to polyacrylate to examine any changes in color parameters in comparison with other additives. Water contact angle, surface roughness, and the color parameters in L*a*b* coordinates were measured, and any differences (ΔE*, ΔC*, ΔH*, ΔL*, Δa*, Δb*) were also calculated after applying the formulated coats on the thermally modified wood. The results indicated that lightness decreased after coating. The Δa* value was also increased after application of the olive leaf extract to the thermally treated wood. In general, total color change (ΔE*) was increased after coating. Reduction of ΔC* was found in the coating containing TiO2 with 10% antioxidant. Also, ΔH* was increased by the use of the polyacrylate coating containing TiO2, compared with other coatings. Application of all of the formulated coatings on the wood surface led to improvement in the water contact angle over the evolution time. On the other hand, coating of the treated wood was responsible for the formation of a smooth surface in comparison with the uncoated thermally modified timber.

13

The influence of plasma-sprayed coatings on surface properties and corrosion resistance of 316L stainless steel for possible implant application

Woźniak Anna, Staszuk Marcin, Reimann Łukasz, Bialas Oktawian, Brytan Zbigniew, Voinarovych Sergii, Kyslytsia Oleksandr, Kaliuzhnyi Sergii, Basiaga Marcin, Adamiak Marcin

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 4

223--243

EN

Herein, we analyzed the morphology of atmospheric plasma-sprayed (APS) coating on medical 316L stainless steel and its influence on the physical and electrochemical properties of implant application. Five types of coatings were examined: hydroxyapatite (HAp), titanium (Ti), zirconium (Zr), Ti/HAp and Zr/HAp. The base properties of the coatings were analyzed via chemical and phase composition, surface topography, surface wettability and in particular the corrosion resistance in Ringer solution in immersed conditions and potentiodynamic test, and EIS analysis. APS coating of pure HAp on 316L stainless steel showed poor cohesive bonding to the substrate material, whereas the application of Ti and Zr interlayer prior to HAp deposition improved surface morphology and coating properties. The beneficial effect of Ti and Zr interlayer under HAp layer on binding was demonstrated. HAp containing coatings (HAp, Ti/HAp and Zr/HAp) show Ca/P ratio greater than 1.8, which may positively influence the differentiation of osteogenic cells and good adhesion to bones. Among the studied materials, the composite coatings with Zr or Zr/HAp showed favorable physicochemical properties and the highest corrosion resistance in Ringer solution.

14

Microstructure and mechanical properties of laser surface-treated Ti13Nb13Zr alloy with MWCNTs coatings

Majkowska-Marzec Beata, Sypniewska Joanna

Advances in Materials Science

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2021

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Vol. 21, nr 4(70)

5--18

EN

Laser surface modification of titanium alloys is one of the main methods of improving the properties of titanium alloys used in implantology. This study investigates the microstructural morphology of a laser-modified surface layer on a Ti13Nb13Zr alloy with and without a carbon nanotube coating deposited by electrophoretic deposition. Laser modification was performed for samples with and without carbon nanotube coating for two different laser powers of 800 W and 900 W and for different scan rates: 3 mm/s or 6 mm/s at 25 Hz, and the pulse duration was 2.25 ms or 3.25 ms. A scanning electron microscope SEM was used to evaluate the surface structure of the modified samples. To observe the heat-affected zones of the individual samples, metallographic samples were taken and observed under an optical microscope. Surface wettability tests were performed using a goniometer. A surface roughness test using a profilograph and a nanoindentation test by NanoTest™ Vantage was also performed. Observations of the microstructure allowed to state that for higher laser powers the surfaces of the samples are more homogeneous without defects, while for lower laser powers the path of the laser beam is clearer and more regular. Examination of the microstructure of the cross-sections indicated that the samples on which the carbon nanotube coating was deposited are characterized by a wider heat affected zone, and for the samples modified at 800 W and a feed rate of 3 mm/s the widest heat affected zone is observed. The wettability tests revealed that all the samples exhibit hydrophilic surfaces and the samples with deposited carbon nanotube coating increase it further. Surface roughness testing showed a significant increase in Ra for the laser-modified samples, and the presence of carbon nanotubes further increased this value. Nanoindentation studies showed that the laser modification and the presence of carbon coating improved the mechanical properties of the samples due to their strength.

15

Comparative analysis of wetting ability of aluminum sheets with different surface roughness parameters by epoxy adhesive

Domińczuk Jacek, Krawczuk Anna

Technologia i Automatyzacja Montażu

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2020

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nr 2

34--40

EN

The article presents the analysis of the wetting ability by Epidian 5 epoxy resin with hardener Z1 of EN AW-2017A aluminum alloy sheets. The material sheets were subjected to the selected methods of processing in order to obtain different parameters of the geometric development of the surface. The energy state of the surface layer was examined on the prepared surfaces, taking the polar and non-polar free surface energy components into account. On the basis of the obtained results, wetting envelopes were determined, which represent the limit value of the surface energy components of the wetting liquid, ensuring good wetting. As part of the research, an analysis of the possibilities of achieving maximum adhesion work between a solid and a liquid in the event of changes in the contact angle was also conducted. This analysis allows one to determine how the parameters of the test adhesive deviate from the ideal, i.e. those for which the surface tension at the interface reaches the minimum value. Based on the results of the analysis, a summary was prepared, showing the ability of the adhesive to wet surfaces with different roughness parameters.

PL

W artykule przedstawiono analizę zdolności zwilżania przez klej Epidian 5 z utwardzaczem Z1 powierzchni blach ze stopu aluminium EN AW-2017A. Blachy poddano wybranym sposobom obróbki w celu uzyskania odmiennych parametrów rozwinięcia geometrycznego powierzchni. Na tak przygotowanych powierzchniach przeprowadzono badania stanu energetycznego warstwy wierzchniej z uwzględnieniem składowej polarnej i niepolarnej swobodnej energii powierzchniowej. Na podstawie otrzymanych wyników wyznaczono krzywe zwilżania, które przedstawiają graniczną wartość składowych swobodnej energii powierzchniowej cieczy zwilżającej, zapewniające uzyskanie dobrego zwilżania. W ramach badań przeprowadzono również analizę możliwości osiągnięcia maksymalnej pracy adhezji między ciałem stałym, a cieczą w przypadku zmian kąta zwilżania. Analiza ta pozwoliła na określenie na ile parametry badanego kleju odbiegają od idealnych, czyli takich, dla których napięcie powierzchniowe na granicy faz osiąga wartość minimalną. W oparciu o uzyskane wyniki analiz dokonano zestawienia obrazującego zdolność kleju do zwilżania powierzchni o różnych parametrach chropowatości.

16

Synthesis of a magnetic ionic liquid ([C12mim]FeCl4) and its interactions with low-rank coal

Li Zhihao, Liu Mingpu, Lin Mengyu, Ma Chuandong, He Meng, Wang Qingbiao, Yu Hao, Li Lin, You Xiaofang

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 3

566--578

EN

he large number of oxygen-containing functional groups present on the surface of low-grade coal contribute to its strong hydrophilic properties and rendering coal beneficiation by flotation challenging. In this study, a magnetic ionic liquid (IL), [C12mim]FeCl4, was developed as a green medium to treat low-rank coal. Notably, the IL can be recovered using a magnetic field. The interactions between the low-rank coal and the IL were analyzed, and the structure and properties of [C12mim]FeCl4 were characterized using Raman spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, and vibrating-sample magnetometry. Moreover, the effects of the newly prepared IL on the wetting properties of low-rank coal were studied using water contact angle measurements. The contact angle of the coal sample treated with the IL increased initially but decreased with subsequent increase in treatment time, indicating a change in coal wettability with time. The results from FT-IR analysis show that the changes in contact angles may be attributed to the changes to the oxygen-containing functional groups at the coal surface upon interaction with the IL, where the content of oxygen-containing functional groups in the treated coal sample initially decreased but subsequently increased with increase in treatment time. X-ray photoelectron spectroscopy analysis confirmed these results. Thus, it can be concluded that [C12mim]FeCl4 initially destroys the oxygen-containing functional groups at the coal surface, resulting in an increase in the water-coal contact angle but subsequently promoting oxidation of the coal surface, hence causing a reduction in the contact angle.

17

Comparison of components and parameters of some sulfide minerals surface tension with regards to stability of mineral-air bubble system

Jańczuk Bronisław, Zdziennicka Anna

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 6

22--31

EN

The measurements of the advancing contact angle of water, glycerol, formamide, ethylene glycol, diiodomethane, α-bromonaphthalene, 1,2,3-tribromopropane on unoxidized and oxidized galena, pyrite, chalcopyrite, djurleite, bornite and covellite at the temperature equal 293 K were made. Additionally, the measurements of the force air bubble detachment from these sulfide minerals including also chalcocite in water were performed. Using the values of the obtained contact angle of water, glycerol, formamide, ethylene glycol, diiodomethane, α-bromonaphthalene, 1,2,3-tribromopropane the components and parameters of the unoxidized and oxidized sulfide minerals surface tension were calculated. For this calculation the van Oss et al. method was applied after analysis of the components and parameters of the surface tension of liquids used for contact angle measurements. Taking into account the contact angle of water on the sulfide minerals, the detachment force of air bubble from these minerals in water was determined using our equation and comparing to that of measured one. As follows from the measurements and calculations the wetting properties of sulfide minerals and the stability of mineral-air bubble depends to a larger extent on the degree of sulfide minerals oxidation than on the type of mineral.

18

An investigation of continuous interaction process between air bubble and various roughness coal surfaces using microbalance

Guo Zhimin, Yang Jianguo, Wang Yuling

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 1

11--23

EN

Surface roughness of particles plays an important role in bubble-particle interaction process. However, the continuous attachment and detachment process have rarely been characterized between the surface of different roughness and air bubble. In this study, the continuous attachment and detachment processes between the surface of different roughness and air bubble were investigated by a highly sensitive microbalance. The bubble–surface interaction process was monitored by a high-speed camera to analyze the geometry parameters, including distance, adhesion diameter, and contact angle. It was found that the bubble-particle attachment time increased with the increase of surface roughness. The magnitude of the repulsive force in the bubble-surface approaching process increased with the increase of surface roughness, while the attractive force in the bubble-particle retracting process decreased monotonically with the surface roughness. The force measured by microbalance was finally compared with the calculated one. The calculated force at the biggest force point also increased with the decrease of surface roughness. These results indicate that coal particles with lower surface roughness, which have less water-filled pores and pillars, is more conducive to flotation due to the lower repulsive force in the bubble-particle attachment process and higher adhesive force in the bubble-particle detachment process, and vice versa.

19

Enhancement of tribological properties and characteristic of polymer matrix composite (UHMWPE reinforced with short fibres of polyester) for Total Disc Replacement (TDR)

Obaid M. N., Radhi S. H.

Journal of Achievements in Materials and Manufacturing Engineering

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2020

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Vol. 102, nr 2

55--65

EN

Purpose: The number of people suffering from Degenerative Disc Disease (DDD) is increasing. The disease causes heavy pain and restrict a number of day-to-day life activities. In extreme cases, the degraded disc is removed under total disc replacement which is usually made up of Ultra-High Molecular Weight Polyethylene (UHMWPE). The material has astounding biocompatible characteristics mechanical properties and wear resistance. However, these characteristics are insufficient in arthroplasty application. Therefore, research investigations are ongoing to improve tribological properties through reinforcement that may result in a composite material of UHMWPE. Thus the current study is aimed at reinforcing UHMWPE with short fibres of polyesters to enhance the tribological properties and surface characteristic so as to improve wear resistance and nourish the fibroblast cells on synthetic disc. Design/methodology/approach: The researcher prepared UHMWPE composite material, reinforced with different weight fractions of short polyester fibres (2, 4, 6, 8 and 10% following hot press method. Further pin-on-disc device was used to study the tribological properties (coefficient of friction and volume of wear). The study tested surface roughness and surface characteristics by atomic force microscopy (AFM) device, hardness by shore D device, contact angle to study the effect of polyester short fibres on wettability of UHMWPE surface and tested the thermal properties and crystalline degree using Differential Scanning Calorimetry measurement (DSC) device. Findings: The results infer that the wear resistance got improved when using 2% w.t polyester though it got decreased initially. However, the value was still more than neat UHMWPE. There was a decrease observed in coefficient of friction, but after 4 w.t% polyester, the coefficient of friction got increased due to increasing percentage of fibres which make it harder and stiff compared to UHMWPE. There was a decline observed in surface roughness due to alignment of the fibres with smooth surface. The contact angle got increased in a moderate range while the roughness enhanced the growth of fibroblast cell. The hardness of composite material got increased, because the fibres turned stiffer and harder than the matrix. DSC results infer the improvements in thermal stability due to high thermal properties of polyester fibres compared to UHMWPE. The degree of crystallinity got increased which in turn enhanced wear resistance, especially at 6 w.t % polyester fibres. There was a mild increase observed in density since the density of polyester is higher than polymer. Research limitations/implications: The major challenge was the dispersion of fibres. Uniform distribution of fibres within the matrix (UHMWPE) was achieved through two steps of mixing processes such as mechanical mixture and twin extruder. In future studies, fatigue tests must be conducted to study the behaviour of prepared composite materials under fatigue cycle. Practical implications: A significant objective is how to connect among different properties to obtain good improvement in tribological and surface properties so as to enhance wear resistance and growth of fibrolase cells. Originality/value: In this study, polymeric short fibres were used as reinforcement with polymeric matrix to enhance the wettability of fibres with matrix. In this way, the bonding among them got increased which supports the tribological, surface, and crystalline behaviour.

20

Evaluation of the contact angle and wettability of hydrophobised lightweight concrete with sawdust

Szafraniec Małgorzata, Barnat-Hunek Danuta

Budownictwo i Architektura

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2020

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Vol. 19, no 2

19--32

EN

The aim of the research presented in the paper was to evaluate the feasibility of using hydrophobic preparations based on organosilicon compounds for protection treatment on the lightweight concrete modified with sawdust. The experimental part of the work concerns the physical and mechanical properties of lightweight concrete and the influence of two hydrophobic agents on the contact angle of the material. Lightweight concrete contact angle (θw) was determined as a time function using one measuring liquid. Water repellent coatings in lightweight concrete structure with the coarse aggregate sawdust (CASD) using electron microscopy were presented. The effectiveness of hydrophobisation of porous lightweight concretes was determined on the basis of the research. For the hydrophobic surface, the contact angle decreased and it depended on the used agents. The lowest contact angle of 40.2° (t=0) was obtained for reference concrete before hydrophobisation and 112.2° after hydrophobisation with a methyl-silicone resin based on organic solvent. The results of scientific research confirm the possibility to produce lightweight concretes modified with CASD with adequate surface protection against external moisture.

PL

Celem badań przedstawionych w pracy była ocena możliwości zastosowania preparatów hydrofobowych na bazie związków krzemoorganicznych do zabezpieczania betonu lekkiego modyfikowanego trocinami. Część doświadczalna pracy dotyczy właściwości fizycznych i mechanicznych betonu lekkiego oraz wpływu dwóch preparatów hydrofobowych na kąt zwilżania materiału. Określono kąt zwilżania betonu lekkiego (θw) w funkcji czasu za pomocą jednej cieczy pomiarowej. Za pomocą mikroskopu elektronowego pokazano powłoki hydrofobowe w strukturze betonu lekkiego, w którym zastosowano trociny jako kruszywo grube (CASD). Na podstawie badań określono skuteczność hydrofobizacji porowatych betonów lekkich. Dla powierzchni hydrofobowej zmniejszył się kąt zwilżania i był on zależny od zastosowanych środków. Najniższy kąt zwilżania 40,2° (t=0) uzyskano dla betonu wzorcowego przed hydrofobizacją i 112,2° po hydrofobizacji żywicą metylo-silikonową na bazie rozpuszczalnika organicznego. Wyniki badań naukowych potwierdzają możliwość otrzymywania betonów lekkich modyfikowanych za pomocą CASD z odpowiednią ochroną powierzchni przed działaniem wilgoci z zewnątrz.