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Special Issue "Collection of Papers in Materials Science from Croatia"

A special issue of Materials (ISSN 1996-1944).

Deadline for manuscript submissions: closed (31 December 2021) | Viewed by 12439

Special Issue Editors

Prof. Dr. Tanja Pušić
E-Mail Website
Guest Editor
Faculty of Textile Technology, University of Zagreb, Zagreb, Croatia
Interests: surface modification of textile materials; electrokinetic phenomena; detergents; textile care; UV functionalization; shedding of particles from textile materials; residual substances; surfactants; adsorption; desorption
Prof. Dr. Mirela Leskovac
E-Mail Website
Guest Editor
Faculty of Chemical Engineering and Technology, University of Zagreb, Zagreb, Croatia
Interests: interfacial phenomena of polymer multiphase systems (composites, nanocomposites and blends) and their synthesis; characterization and structure–property relationships; filler functionalization; surface engineering; adhesion materials; additives for polymer materials
Dr. Tihana Dekanić
E-Mail Website
Guest Editor Assistant
Faculty of Textile Technology, University of Zagreb, Zagreb, Croatia
Interests: textile and leather finishing and care; alternative washing methods; auxiliaries and enzymes in finishing and care; garment finishing; optical brighteners and UV absorbers in detergents; UV functionalization; hygiene and laundering of hospital protective textiles

Special Issue Information

Dear Colleagues,

The materials present a research challenge in chemical engineering, textile engineering, biotechnical, biomedical, medical, natural science and interdisciplinary fields of science. We would like that Croatian scientists present significant research potential in the development of materials, achievements in theoretical and experimental work and innovative and creative engineering approaches. Original papers, communications and reviews focused on new, sustainable, advanced and smart materials from macro to nano level, structures, surface modifications, mechanical properties, thermal properties, different characterization techniques, compatibility, technological solutions, and process improvements dedicated to progress in materials sciences are welcome.

We have the pleasure to motivate and invite you to submit a manuscript to the Special Issue “Collection of Papers in Materials Science from Croatia” for the journal Materials. Let us present research novelties in materials science; Let us increase the visibility of Croatian research potentials.

Prof. Dr. Tanja Pušić
Prof. Dr. Mirela Leskovac
Dr. Tihana Dekanić
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2300 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • new materials
  • characterization
  • surface modification
  • synthesis
  • structure properties relationships
  • environmental approach or environmental issues

Published Papers (17 papers)

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Research

Article
Hydrothermal Synthesis of Chitosan and Tea Tree Oil on Plain and Satin Weave Cotton Fabrics
Materials 2022, 15(14), 5034; https://doi.org/10.3390/ma15145034 - 20 Jul 2022
Viewed by 262
Abstract
The paper aimed at enhancing the antimicrobial activity of chitosan by using tea tree essential oil with the purpose of durably finishing cotton fabrics for use in a hospital environment. The influence of crosslinkers and catalysts on the possibility of obtaining stable bonds [...] Read more.
The paper aimed at enhancing the antimicrobial activity of chitosan by using tea tree essential oil with the purpose of durably finishing cotton fabrics for use in a hospital environment. The influence of crosslinkers and catalysts on the possibility of obtaining stable bonds using hydrothermal in situ synthesis between cellulosic material and chitosan with and without tea tree essential oil was investigated in detail. The morphology of the sample surface before and after the treatment and textile care cycle was investigated using a field emission scanning electron microscopy (FE-SEM) and indicated the presence of chitosan and a thin film on all treated samples, which showed durability of the treatment. The FTIR spectra obtained by Fourier transform infrared spectroscopy (FTIR) using attenuated total reflection measurement technique (ATR) analysis, showed that all the samples tested recorded physicochemical changes in the structure. The analysis of the samples on the goniometer proved the hydrophilicity of the materials, with a film forming on the surface of the treated samples, which is extremely beneficial given the end use of dressing samples to promote wound healing. The presence of a significant amount of bound chitosan with tea tree oil was confirmed by measuring the mass per unit area of the samples after the treatment and textile care cycles. The results of antimicrobial efficacy show that the materials treated with chitosan were resistant to bacteria and fungi in most cases, but only the samples treated in Bath I showed a zone of inhibition against the fungus Candida albicans, indicating the positive effect of tea tree essential oil. Full article
(This article belongs to the Special Issue Collection of Papers in Materials Science from Croatia)
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Article
Impact of Fabric Construction on Adsorption and Spreading of Liquid Contaminations
Materials 2022, 15(6), 1998; https://doi.org/10.3390/ma15061998 - 08 Mar 2022
Viewed by 414
Abstract
A contamination on a textile material is defined as an undesirable, local formation that deviates in appearance from the rest of the material. In this paper the relationship between the shape and surface of liquid contaminations and the firmness factor of woven fabric [...] Read more.
A contamination on a textile material is defined as an undesirable, local formation that deviates in appearance from the rest of the material. In this paper the relationship between the shape and surface of liquid contaminations and the firmness factor of woven fabric is investigated. The interdependence of constructional and structural parameters of raw and bleached cotton fabrics were analysed. The results show that selected contaminations are distributed differently, primarily depending on the construction characteristics of the fabric, type of contamination and hydrophilicity of cotton fabric. Full article
(This article belongs to the Special Issue Collection of Papers in Materials Science from Croatia)
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Article
Sustainable Alkaline Hydrolysis of Polyester Fabric at Low Temperature
Materials 2022, 15(4), 1530; https://doi.org/10.3390/ma15041530 - 18 Feb 2022
Cited by 2 | Viewed by 608
Abstract
High crystallinity leads to low hydrophilicity of fabric made of (poly(ethylene terephthalate)) fibers (PET) causing problems in finishing, washing, and dyeing processes. To improve these properties, the surface of PET fibers is usually modified by hydrolysis. Alkaline hydrolysis is a conventional process usually [...] Read more.
High crystallinity leads to low hydrophilicity of fabric made of (poly(ethylene terephthalate)) fibers (PET) causing problems in finishing, washing, and dyeing processes. To improve these properties, the surface of PET fibers is usually modified by hydrolysis. Alkaline hydrolysis is a conventional process usually performed at a temperature higher than 100 °C for more than 1 h. However, the use of strong alkali and high processing temperatures (>100 °C) can lead to fabric damage and a negative impact on the environment. Therefore, in this paper, the possibility of hydrolysis of the PET fibers in the fabric in a sustainable, energy-efficient process was researched. The influence of low temperature (60–100 °C) and an accelerator (a cationic surfactant HDTMAC) to PET alkaline hydrolysis was studied through weight loss, the loss in breaking force, and fiber morphology. The kinetics of PET dissolution in 1.5 mol cm−3 NaOH at low temperature with and without the addition of HDTMAC was determined and the activation energy was calculated according to the theoretical model. It has been confirmed that PET hydrolysis can be carried out in 1.5 mol cm−3 NaOH with the addition of HDTMAC as an accelerator at 80 °C for 10 min. This process is more economically and energetically acceptable than the conventional process, and is therefore more sustainable. Full article
(This article belongs to the Special Issue Collection of Papers in Materials Science from Croatia)
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Article
Heat as a Conductivity Factor of Electrically Conductive Yarns Woven into Fabric
Materials 2022, 15(3), 1202; https://doi.org/10.3390/ma15031202 - 05 Feb 2022
Viewed by 455
Abstract
In recent years, more and more researchers have been focused on electrically conductive textiles that generate heat or transmit electrical signals and energy to embedded electrical components. In this paper, the dissipation of heat due to the flow of electric current at given [...] Read more.
In recent years, more and more researchers have been focused on electrically conductive textiles that generate heat or transmit electrical signals and energy to embedded electrical components. In this paper, the dissipation of heat due to the flow of electric current at given voltages is investigated, and at the same time it is determined how this heat affects the change in the electrical resistance of the electrically conductive yarn in the immediate surroundings. Three fabric samples were woven in a plain weave with three types of different electrically conductive yarns. Three electrically conductive yarns are woven in parallel in the weft direction and separated from each other by one polyester (PES) yarn due to electrical insulaton. Conductive yarns are electrically connected so that the outer yarns are used for heating by the flow of electric current at a certain constant voltage, and the central yarn is used only to measure changes in electrical resistance. When electrothermally conductive fabrics are subjected to certain voltages over time, experimental results have shown that resistance values increase over a short period of time and then gradually decrease, while the temperature gradually increases and stabilizes over time. Based on the analysis of the obtained results of the ratio between the values of applied voltage and temperature to the electrically conductive yarns, the value of thermal dissipation in conductive yarns can be calculated in advance depending on the applied voltage. Furthermore, the obtained results can be further used in applications where conductive yarns are used as heaters for realistic prediction of the obtained heat. Full article
(This article belongs to the Special Issue Collection of Papers in Materials Science from Croatia)
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Article
The Effect of Ultrasonic Treatment on the Binding of the Inclusion Complex β-Cyclodextrin-peppermint Oil with Cellulose Material
Materials 2022, 15(2), 470; https://doi.org/10.3390/ma15020470 - 08 Jan 2022
Viewed by 376
Abstract
The purpose of the research was to measure the increase in the binding of inclusion complexes β-cyclodextrin-peppermint oil (β-CD_PM) to cellulose in cotton and cotton/polyester material with BTCA as the crosslinking agent by applying an ultrasonic bath at room temperature and a frequency [...] Read more.
The purpose of the research was to measure the increase in the binding of inclusion complexes β-cyclodextrin-peppermint oil (β-CD_PM) to cellulose in cotton and cotton/polyester material with BTCA as the crosslinking agent by applying an ultrasonic bath at room temperature and a frequency of 80 kHz for 10 min. After sonication, the samples were left in a bath for 24 h after which they were dried, thermocondensed and subjected to a number of wash cycles. The treated samples were analysed with Attenuated total reflection (ATR) units heated up to 300 °C (Golden Gate (FTIR-ATR)) to monitor chemical changes indicative of crosslinking, while physico-chemical changes in the samples were monitored by using Fourier transform infrared spectroscopy (FTIR-ATR). Mechanical properties were measured according to EN ISO 13934-1:1999, and coloristic changes were evaluated by the whiteness degree according to CIE (WCIE) and the yellowing index (YI), while antimicrobial activity was determined according to AATCC TM 147-2016. The results show a physico-chemical modification of the UZV-treated cellulosic material. Moreover, partial antimicrobial efficacy on Gram-negative bacteria was confirmed for treated fabrics. Full article
(This article belongs to the Special Issue Collection of Papers in Materials Science from Croatia)
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Article
The Structure and Compression of Medical Compression Stockings
Materials 2022, 15(1), 353; https://doi.org/10.3390/ma15010353 - 04 Jan 2022
Viewed by 471
Abstract
This paper lays out standards of compression stockings and their classification into classes. The analysis of knitted fabric structure parameters, elongation and compression of moderate- and high-compression stockings was conducted. Stocking compression on specific parts of the stocking leg was measured on three [...] Read more.
This paper lays out standards of compression stockings and their classification into classes. The analysis of knitted fabric structure parameters, elongation and compression of moderate- and high-compression stockings was conducted. Stocking compression on specific parts of the stocking leg was measured on three sizes of a wooden leg model. For moderate-compression stockings, compression above the ankle was 32 hPa. For high-compression stockings, compression above the ankle was 60 hPa. Both groups of the analyzed compression stockings were made on modern one-cylinder hosiery automats. The legs of the stockings were made in single inlaid jersey 1 + 1. Both yarns were elastane covered. The finer yarn formed loops and its knitting into a course was significantly larger than in the other yarn, which was much coarser and does not form loops but “lay the weft in a bent way”. The smallest elongation of knitted fabric was above the ankle, where the highest compression was achieved, while the largest elongation was under the crotch, where the stocking leg exerted the smallest compression on the surface. The leg of the compression stocking acted as a casing that imposed compression on the leg and often reinforced it to be able to sustain compression loads. Full article
(This article belongs to the Special Issue Collection of Papers in Materials Science from Croatia)
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Article
Metal Content and Structure of Textiles in Textile Metal Threads in Croatia from 17th to 20th Century
Materials 2022, 15(1), 251; https://doi.org/10.3390/ma15010251 - 29 Dec 2021
Viewed by 486
Abstract
Textile metal threads were used to decorate historical Croatian textiles. There are three basic types of metal threads usually used on historical textiles in Croatia. These are narrow stripes, wires, and combined metal textile yarn called “srma”, made of metal thread spirally wrapped [...] Read more.
Textile metal threads were used to decorate historical Croatian textiles. There are three basic types of metal threads usually used on historical textiles in Croatia. These are narrow stripes, wires, and combined metal textile yarn called “srma”, made of metal thread spirally wrapped around the nonmetal textile yarn. Textile yarns were made of silk, linen, wool, or cotton. Metal threads were primarily made of gold, silver, and copper, and different alloys of these metals or threads are layered in the structure. Analysis of metal threads with three different methods was made and the most adequate method for the analysis of metal threads from historical textiles was established. Metal thread analysis was performed with scanning electron microscopy with an energy-dispersive X-ray detector (SEM-EDX), which was determined to be the most suitable for the analysis of historical textiles if cross-section analysis of metal threads is also performed. Textile threads from combined metal textile threads were analysed with a light microscope. This information of the metal threads’ content and structure as well as the composition of textile thread can lead to an understanding of the technology of production threads and also temporal and spatial dating of textile objects which is helpful to conservators and restorers of valuable historical textiles. Full article
(This article belongs to the Special Issue Collection of Papers in Materials Science from Croatia)
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Article
Particle Characterization of Washing Process Effluents by Laser Diffraction Technique
Materials 2021, 14(24), 7781; https://doi.org/10.3390/ma14247781 - 16 Dec 2021
Cited by 1 | Viewed by 676
Abstract
The dominant type of polymer particles in water, sediment, and various organisms partly derives from natural and synthetic fibres released in the washing process. Pollution of aquatic recipients with these particles poses an interdisciplinary problem throughout the world. Wastewater from washing represents a [...] Read more.
The dominant type of polymer particles in water, sediment, and various organisms partly derives from natural and synthetic fibres released in the washing process. Pollution of aquatic recipients with these particles poses an interdisciplinary problem throughout the world. Wastewater from washing represents a dispersion system with different particle sizes that is also loaded with the source of the particles. Due to this complex system, the qualification and quantification of this type of pollution is difficult. In this paper, the laser diffraction technique was applied to characterize particles in effluents from washing and rinsing materials made of a mixture of cotton and polyester. The results obtained through the analysis prove that the laser diffraction technique is acceptable for the characterization of a composite effluent sample. The advanced statistical technique of multivariate analysis confirmed the interrelationship of the parameters of this complex dispersion system. Full article
(This article belongs to the Special Issue Collection of Papers in Materials Science from Croatia)
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Article
Measurement Method for the Simultaneous DeterMination of Thermal Resistance and Temperature Gradients in the DeterMination of Thermal Properties of Textile Material Layers
Materials 2021, 14(22), 6853; https://doi.org/10.3390/ma14226853 - 13 Nov 2021
Cited by 1 | Viewed by 605
Abstract
The thermal properties of most clothing products are still not designed according to engineering science due to the lack of simple and acceptable measuring equipment and methods; the type of thermal insulation material, the number of layers of clothing and their thickness are [...] Read more.
The thermal properties of most clothing products are still not designed according to engineering science due to the lack of simple and acceptable measuring equipment and methods; the type of thermal insulation material, the number of layers of clothing and their thickness are thus chosen empirically. The novelty of this study was the development of a new measuring device and method for simultaneous measurements in the determination of the thermal resistance in one or more textile material layers, such as in multilayer composite clothing. Temperature gradients of textile material layers are presented, as well as the theoretical principles of operation and practical results. Four materials for the production of protective jackets were selected, from which different combinations of composite clothing were constructed and the thermal parameters were measured with a new method and a new device, both individually for the built-in materials and for the composites. Subsequently, five test jackets with the same arrangement of textile material layers as the previously tested composites were produced, and measurements of important thermal parameters were recorded with a thermal mannequin. The determined temperature gradients and measurement results are presented, and based on these it was determined that the total thermal resistance was not equal to the algebraic sum of the resistances of the individual textile material layers in the horizontal position; it was, however, higher, increasing from 30% to 94% due to small air layers caused by crimping and protruding fibres of yarn in the textile fabrics. The same textile material layers built into clothing in the vertical position allowed the formation of significantly wider air layers that increased the thermal resistance by between 2.5 and 9 times. Full article
(This article belongs to the Special Issue Collection of Papers in Materials Science from Croatia)
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Article
Trichromatic Vat Dyeing of Cationized Cotton
Materials 2021, 14(19), 5731; https://doi.org/10.3390/ma14195731 - 30 Sep 2021
Cited by 3 | Viewed by 616
Abstract
This article deals with cationization of cotton during mercerization and its effects on trichromatic vat dyeing. If cationization is carried out during the after-treatment, regardless of cotton pretreatment, the reaction takes place on the surface and blocks cellulose groups, subsequently resulting in uneven [...] Read more.
This article deals with cationization of cotton during mercerization and its effects on trichromatic vat dyeing. If cationization is carried out during the after-treatment, regardless of cotton pretreatment, the reaction takes place on the surface and blocks cellulose groups, subsequently resulting in uneven coloration. However, when cationization is carried out with an epihalohydrin during the mercerization process, new cellulose is formed in which the cationic compound is uniformly distributed and trapped between cellulose chains, resulting in uniform coloration after the dyeing process. The reaction time for the process during mercerization is 24 h, thus a more favorable process was researched. Based on electrokinetic analysis, it was found that 5 h was sufficient for the reaction with 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (CHPTAC). The cationization of cotton contributed to the processes of vat dyeing. The change in charge upon cationization resulted in very high adsorption of vat-dye anions, indicating that ionic bonding occurred in addition to van der Waals forces. The color depth improved by more than 10 times. It should be emphasized that the colors with higher chroma and targeted color hue, especially in trichromatic dyeing, were obtained on cationized cotton, in contrast to standard cotton fabrics. The color differences obtained under the different light sources indicate the occurrence of metamerism. Considering the color fastness to laundering, vat-dyed cationized fabrics of all colors may be used in hospitals or other environments where high hygiene and oxidative bleaching are required. Full article
(This article belongs to the Special Issue Collection of Papers in Materials Science from Croatia)
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Article
Electrosprayed Chitosan–Copper Complex Microspheres with Uniform Size
Materials 2021, 14(19), 5630; https://doi.org/10.3390/ma14195630 - 28 Sep 2021
Cited by 1 | Viewed by 812
Abstract
Chitosan-based nano- and microspheres have shown great potential in a broad range of applications, including drug delivery, bone tissue engineering, wastewater treatments, etc. The preparation of uniformly sized spheres with controlled morphology and microstructure is still a challenge. This work investigates the influence [...] Read more.
Chitosan-based nano- and microspheres have shown great potential in a broad range of applications, including drug delivery, bone tissue engineering, wastewater treatments, etc. The preparation of uniformly sized spheres with controlled morphology and microstructure is still a challenge. This work investigates the influence of cupric ions (Cu2+) on the size, shape, morphology and stability of electrosprayed chitosan–copper (CHT–Cu2+) complex microspheres, using chitosans with different degrees of deacetylation. The dynamic viscosity of CHT–Cu2+ solutions was measured by Höppler viscometer, while attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) was used for the identification of dried microspheres. The size, shape and morphology of microspheres were analyzed by light microscope and scanning electron microscopy (SEM), while stability of dried microspheres was evaluated in different buffer solutions. The volume ratio of wet and dry microspheres was assessed based on the estimated diameter of microspheres. The higher concentration of Cu2+ ions resulted in a decrease in viscosity of CHT–Cu2+ solutions and volume ratio of prepared microspheres. Changes in the intensities and wave numbers of absorption bands of amino and hydroxyl groups, amide I and amide II suggested that the nitrogen and oxygen atoms in chitosan are coordinating the cupric ions. Micrographs obtained by light microscope and SEM showed that all prepared samples are spherical. The increase of cupric ions concentration changed the topography of microspheres and decreased their size. These results indicated the successful electrospraying of CHT–Cu2+ microspheres with uniform size and good stability in aqueous medium. Full article
(This article belongs to the Special Issue Collection of Papers in Materials Science from Croatia)
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Article
The Influence of Iron Ions on Optical Brighteners and Their Application to Cotton Fabrics
Materials 2021, 14(17), 4995; https://doi.org/10.3390/ma14174995 - 01 Sep 2021
Cited by 2 | Viewed by 827
Abstract
The influence of iron ions at concentrations of 0.2, 0.5, and 1.0 g/L on optical brighteners of the groups stilbene and biphenyl in solution and on cotton fabric was investigated. Both groups of optical brighteners are intended for detergent formulations. The influence of [...] Read more.
The influence of iron ions at concentrations of 0.2, 0.5, and 1.0 g/L on optical brighteners of the groups stilbene and biphenyl in solution and on cotton fabric was investigated. Both groups of optical brighteners are intended for detergent formulations. The influence of iron ions was studied by absorption and fluorescence spectra in solution and by whiteness degree, identifying color differences using CIEL*a*b* coordinates and Ultraviolet Protection Factor (UPF) of cotton fabrics. The obtained results in solutions and cotton fabrics showed different behavior of optical brighteners stilbene and biphenyl in the presence of iron. Stilbene compounds with metal ions produced new species capable of absorbing in the UV-B region of the spectrum. A biphenyl compound in combination with iron had no effect on the absorption properties. Both optical brighteners were influenced by iron ions in the sense of fluorescence quenching. The influence of iron ions in single- and two-bath treatments of cotton fabrics after one cycle on whiteness degree and UPF was negligible. Full article
(This article belongs to the Special Issue Collection of Papers in Materials Science from Croatia)
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Article
Revealing the Origin: The Secrets of Textile Fragments Hidden Inside the 19th Century Chasuble from Dubrovnik
Materials 2021, 14(16), 4650; https://doi.org/10.3390/ma14164650 - 18 Aug 2021
Cited by 1 | Viewed by 699
Abstract
This paper presents the analysis carried out during the textile conservation–restoration process with the goal to reveal the secrets of textile fragments hidden inside the 19th century chasuble from Dubrovnik. The discovered textile fragments were investigated by modern instrumental methods and compared with [...] Read more.
This paper presents the analysis carried out during the textile conservation–restoration process with the goal to reveal the secrets of textile fragments hidden inside the 19th century chasuble from Dubrovnik. The discovered textile fragments were investigated by modern instrumental methods and compared with the original textile from the 19th century set of liturgical vestments, which the chasuble belongs to. In addition, all other old repairs and treatments on the chasuble that had significant impact on the historic textile over time were investigated and assessed. The polymer type of the fibres was established by microscopic examination and infrared (ATR FT-IR) spectroscopy. A comparison of type of fibres and textile construction parameters, both from fragments and from the original textile, was carried out in order to determine their possible associations. Based on UV-Vis and HPLC identification of chemical composition of dyes in extracts from textile fibres, both from textile fragments, old repairs and authentic historic textile, it was possible to designate some common characteristics of dyes as important factors in determining its authenticity. Full article
(This article belongs to the Special Issue Collection of Papers in Materials Science from Croatia)
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Article
PCL-Coated Multi-Substituted Calcium Phosphate Bone Scaffolds with Enhanced Properties
Materials 2021, 14(16), 4403; https://doi.org/10.3390/ma14164403 - 06 Aug 2021
Cited by 1 | Viewed by 737
Abstract
Ionic substitutions within the hydroxyapatite lattice are a widely used approach to mimic the chemical composition of the bone mineral. In this work, Sr-substituted and Mg- and Sr-co-substituted calcium phosphate (CaP) scaffolds, with various levels of strontium and magnesium substitution, were prepared using [...] Read more.
Ionic substitutions within the hydroxyapatite lattice are a widely used approach to mimic the chemical composition of the bone mineral. In this work, Sr-substituted and Mg- and Sr-co-substituted calcium phosphate (CaP) scaffolds, with various levels of strontium and magnesium substitution, were prepared using the hydrothermal method at 200 °C. Calcium carbonate skeletons of cuttlefish bone, ammonium dihydrogenphosphate (NH4H2PO4), strontium nitrate (Sr(NO3)2), and magnesium perchlorate (Mg(ClO4)2) were used as reagents. Materials were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Whole powder pattern decomposition refinements of XRD data indicated that increased magnesium content in the Mg- and Sr-co-substituted scaffolds was related to an increased proportion of the whitlockite (WH) phase in the biphasic hydroxyapatite (HAp)/WH scaffolds. In addition, refinements indicate that Sr2+ ions have replaced Ca2+ sites in the WH phase. Furthermore, PCL-coated Mg-substituted and Sr- and Mg-co-substituted scaffolds, with the HAp:WH wt. ratio of 90:10 were prepared by vacuum impregnation. Results of compression tests showed a positive impact of the WH phase and PCL coating on the mechanical properties of scaffolds. Human mesenchymal stem cells (hMSCs) were cultured on composite scaffolds in an osteogenic medium for 21 days. Immunohistochemical staining showed that Mg-Sr-CaP/PCL scaffold exhibited higher expression of collagen type I than the Mg-CaP/PCL scaffold, indicating the positive effect of Sr2+ ions on the differentiation of hMSCs, in concordance with histology results. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis confirmed an early stage of osteogenic differentiation. Full article
(This article belongs to the Special Issue Collection of Papers in Materials Science from Croatia)
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Article
Natural Dyeing of Cellulose and Protein Fibers with the Flower Extract of Spartium junceum L. Plant
Materials 2021, 14(15), 4091; https://doi.org/10.3390/ma14154091 - 22 Jul 2021
Cited by 7 | Viewed by 964
Abstract
In this study, the natural dye was extracted from Spartium junceum L. (SJL) flowers and applied on cellulose (cotton) and protein (wool) fabric. Fabrics were pre-mordant with alum prior to the dyeing process. Considering the global requirements on zero waste and green policy, [...] Read more.
In this study, the natural dye was extracted from Spartium junceum L. (SJL) flowers and applied on cellulose (cotton) and protein (wool) fabric. Fabrics were pre-mordant with alum prior to the dyeing process. Considering the global requirements on zero waste and green policy, the dyeing process was intended to be as much as possible environmentally friendly but still effective. Therefore, mordant concentration was optimized due to the reduction of the negative impact. The efficiency of the dyeing process was investigated by examination of fabrics’ color characteristics and colorfastness to washing properties. In this paper, we have proved that the extracted dye from Spartium junceum L. is an acidic dye (mordant dye) which is more applicable for the treatment of wool fabrics. In this paper, it was proved that phytochemicals responsible for coloring are part of the flavonoids group. The UV absorption spectra of extracted dye show 4 bands in the region of λmax 224, 268, 308 and 346 nm which are ascribed to bands characteristic for flavonoids. Wool fabric pre-mordant with 3% alum and dyed shows great chromatic (C*) properties where C* value is in a range from 47.76 for unwashed samples to 47.50 for samples after 5 washing cycles and color hue (h°) is in a range 82.13 for unwashed samples to 81.52 for samples after 5 washing cycles. The best result regarding the colorfastness properties is shown by the wool sample treated with 3% alum after 5 washing cycles (total difference in color (Delta E*) = 0.87). These results confirm that metal (Al) from alum mordant make strong chemical bonds with wool substrate and dye since Delta E* values decrease in comparison to Delta E* values of the cotton samples treated the same way. The results revealed it is possible to reduce the concentration of mordant up to 3% and obtain satisfactory results regarding the colorfastness. Nevertheless, future research will go in the direction of replacing synthetic mordant with a more environmentally friendly one. Full article
(This article belongs to the Special Issue Collection of Papers in Materials Science from Croatia)
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Article
Combining Raman Spectroscopy, DFT Calculations, and Atomic Force Microscopy in the Study of Clinker Materials
Materials 2021, 14(13), 3648; https://doi.org/10.3390/ma14133648 - 30 Jun 2021
Cited by 1 | Viewed by 732
Abstract
Raman spectroscopy and Raman mapping analysis, combined with density functional theory calculations were applied to the problem of differentiating similar clinker materials such as alite and belite. The Portland cement clinker 217 (further: clinker) was analysed using colocalised Raman mapping and atomic force [...] Read more.
Raman spectroscopy and Raman mapping analysis, combined with density functional theory calculations were applied to the problem of differentiating similar clinker materials such as alite and belite. The Portland cement clinker 217 (further: clinker) was analysed using colocalised Raman mapping and atomic force microscopy mapping, which provided both spatial and chemical information simultaneously. The main constituents found in the clinker were alite, belite, portlandite, amorphous calcium carbonate, and gypsum. Since phonon bands of alite and belite greatly overlap, and their distinction is important for the hydration process during cement setting, we provided the calculated phonon density of states for alite Ca3SiO5 (<M>Pc structure) and belite Ca2SiO4P21/n structure) here for the first time. Both calculated phonon densities have similar distribution of phonon modes, with a gap between 560 and 810 cm−1. A comparison of the calculated phonon frequencies for Ca3SiO5 and Ca2SiO4 shows that the lowest calculated phonon frequency of β-Ca2SiO4 lies at 102 cm−1, while for <M>Pc alite the lowest phonon frequency is predicted at 27 cm−1. Low frequency Raman spectroscopy could therefore be used for a clearer distinction of these two species in a clinker material. Full article
(This article belongs to the Special Issue Collection of Papers in Materials Science from Croatia)
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Article
Selenite Substituted Calcium Phosphates: Preparation, Characterization, and Cytotoxic Activity
Materials 2021, 14(12), 3436; https://doi.org/10.3390/ma14123436 - 21 Jun 2021
Cited by 6 | Viewed by 1110
Abstract
The aim of this study was to prepare a biomimetic selenium substituted calcium phosphate system for potential application in osteosarcoma therapy. Calcium phosphate (CaP) systems substituted with selenite ions were prepared by the wet precipitation method, using biogenic CaCO3 (derived from cuttlefish [...] Read more.
The aim of this study was to prepare a biomimetic selenium substituted calcium phosphate system for potential application in osteosarcoma therapy. Calcium phosphate (CaP) systems substituted with selenite ions were prepared by the wet precipitation method, using biogenic CaCO3 (derived from cuttlefish bone), CO(NH2)2-H3PO4, and Na2SeO3·5H2O as reagents. Starting reaction mixtures were prepared based on the formula for selenite-substituted hydroxyapatite, Ca10(PO4)6-x(SeO3)x(OH)2, with Ca/(P + Se) molar ratio of 1.67 and Se/(P + Se) molar ratio of: 0, 0.01, 0.05, and 0.10, respectively. The prepared CaP powders were characterized by Fourier transform infrared spectrometry, elemental analysis, scanning electron microscopy, X-ray powder diffraction analysis and Rietveld refinement studies. Phase transformation and ion release were analyzed during 7 days of incubation in simulated body fluid at 37 °C. The metabolic activity of healthy and osteosarcoma cell lines was assessed by cell cytotoxicity and viability test. The as-prepared powders were composed of calcium-deficient carbonated hydroxyapatite (HAp), octacalcium phosphate (OCP), and amorphous calcium phosphate (ACP). Along with the selenite substitution, the presence of Sr2+, Na+, and Mg2+ was detected as a result of using cuttlefish bone as a precursor for Ca2+ ions. Inductively coupled plasma mass spectrometry analysis showed that the Se/(P + Se) molar ratios of selenite substituted powders are lower than the nominal ratios. Heat treated powders were composed of HAp, α-tricalcium phosphate (α-TCP) and β-tricalcium phosphate (β-TCP). Doping CaP structure with selenite ions improves the thermal stability of HAp. The powder with the Se/(P + Se) molar ratio of 0.007 showed selective toxicity to cancer cells. Full article
(This article belongs to the Special Issue Collection of Papers in Materials Science from Croatia)
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