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Orhan, Mehmet
Publications (5 of 5) Show all publications
Guclu, N., Duzyer Gebizli, S. & Orhan, M. (2023). Development of polycaprolactone‐based electrospun pH‐sensitive sensors as instant colorimetric indicators for food packaging. Coloration Technology
Open this publication in new window or tab >>Development of polycaprolactone‐based electrospun pH‐sensitive sensors as instant colorimetric indicators for food packaging
2023 (English)In: Coloration Technology, ISSN 1472-3581, E-ISSN 1478-4408Article in journal (Refereed) Published
Abstract [en]

In the present study, polycaprolactone/polyethylene glycol (PCL/PEG) electrospun nanofibres with different anthocyanin (1%, 2%, 3%, and 5%) were fabricated for the instant measurement of pH, especially for applications—such as food freshness detection—where quick response is required. The solution, surface, chemical, thermal, wettability, mechanical, and release properties of the samples were evaluated by viscosity measurements, scanning electron microscopy (SEM), Fourier-transform infrared (FTIR), contact angle measurements, and tensile tests, respectively. The colorimetric analyses were also investigated against the solutions at different pH values and bacterial solutions. Finally, the on-site performance of the sensor was evaluated. Anthocyanin addition initially lowered the solution viscosity, resulting in thinner fibres with a diameter of 288 nm. The diameters were increased up to 395 nm with the increasing anthocyanin. Anthocyanin addition enhanced the wettability and the mechanical properties, and the contact angles decreased to 43°. The highest modulus was observed for 1% anthocyanin, with a value of 6.162. The release experiments revealed that the anthocyanin-loaded samples released a large amount of anthocyanin (between ~12% and 38%) in the first 15 s. The colorimetric analyses showed that PCL/PEG nanofibre mats with 2% and 3% anthocyanin concentrations were the most capable pH-sensitive sensors for detecting pH changes from 2 to 8. As a result, it can be concluded that 3% anthocyanin is the threshold value for the production of the anthocyanin-loaded nanofibre mats, and these structures are promising for the instant detection of pH proved by the on-site application. 

National Category
Textile, Rubber and Polymeric Materials
Identifiers
urn:nbn:se:hb:diva-29924 (URN)10.1111/cote.12701 (DOI)000998851000001 ()2-s2.0-85161454906 (Scopus ID)
Available from: 2023-06-19 Created: 2023-06-19 Last updated: 2024-02-01Bibliographically approved
Duzyer Gebizli, S., Guclu, N., Tiritoglu, M., Tezel, S. & Orhan, M. (2023). Reversible Thermochromic Polycaprolactone Nanofibers for Repetitive Usage. Fibers And Polymers, 24(10), 3393-3403
Open this publication in new window or tab >>Reversible Thermochromic Polycaprolactone Nanofibers for Repetitive Usage
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2023 (English)In: Fibers And Polymers, ISSN 1229-9197, E-ISSN 1875-0052, Vol. 24, no 10, p. 3393-3403Article in journal (Refereed) Published
Abstract [en]

Color change technology offers unique and challenging opportunities. Thermo-responsive color-changing nanofibers with reversibility have great potential as thermal sensors due to their increased sensitivity and fast response. Herein, polycaprolactone (PCL) nanofibers were produced by adding a leuco-based thermochromic dye with various concentrations (1%, 3%, and 5% wt corresponding to PCL1, PCL3, and PCL5, respectively). The color-changing properties with repetitive heating and cooling were studied, and the effect of dye concentration on the nanofiber properties was determined. The surface properties, dye presence, thermal and mechanical properties were analyzed by SEM–EDS, FTIR, DSC, and tensile tests. Finally, the color change properties were monitored by 1000 heating and cooling cycles between 20 and 40 °C. Thermochromic PCL nanofibers were successfully produced by electrospinning. However, some agglomerates were observed on the nanofibers with increasing dye concentration in SEM images. It was seen that the optimum dye concentration was 3% in terms of the electrospinnability. For PCL5, both presence of carbon, oxygen, nitrogen, and fluorine in EDS spectra, the shifted peaks at 2917 and 2849 cm−1, and the new peaks at 1558, 1517, 1330, 1274, 1213 and 883 cm−1 in FTIR spectra confirmed that dye had been successfully incorporated into the PCL structure. The dye addition caused a decrease in the crystallization degrees, which resulted in lower mechanical properties. PCL5 had the lowest modulus. Color measurements showed that 1% of dyes concentration was not sufficient for the thermochromic property, and the color change was still visually detectable for PCL3 and PCL5 even after 1000 heating and cooling cycles. Color change activation temperature (TA) was confirmed between 30 and 32 °C, and the stability of color change was confirmed for 1000 heating and cooling cycles. After 1000 heating and cooling cycles, the color change was still detectable for PCL3 and PCL5. Consequently, this study showed that reversible thermochromic PCL nanofibers could be promising materials for future sensor applications.

Keywords
Thermochromic nanofibers, Electrospinning, Color change, Polycaprolactone
National Category
Polymer Technologies
Identifiers
urn:nbn:se:hb:diva-31317 (URN)10.1007/s12221-023-00323-4 (DOI)001060379800008 ()2-s2.0-85168994569 (Scopus ID)
Available from: 2024-01-16 Created: 2024-01-16 Last updated: 2024-02-01Bibliographically approved
Orhan, M. (2021). Wrinkle recovery and performance properties of viscose surface treated with different crosslinking agents. Journal of the Faculty of Engineering and Architecture of Gazi University, 36(2), 883-896
Open this publication in new window or tab >>Wrinkle recovery and performance properties of viscose surface treated with different crosslinking agents
2021 (English)In: Journal of the Faculty of Engineering and Architecture of Gazi University, ISSN 1300-1884, Vol. 36, no 2, p. 883-896Article in journal (Refereed) Published
Abstract [en]

Cellulosic-based surfaces, such as viscose and linen, tend quickly to wrinkle, and this is an undesirable property during uses. In this study, it is aimed to investigate their effects on formaldehyde amount, color, tear and tear resistance, modulus of elasticity, softness, and wrinkle recovery angle of viscose surface after applying three different cross-linking chemicals. It has been observed that cross-linking agents had bound to viscose surface, and cross-links were formed between adjacent fibers. Although free formaldehyde values were positively below 75 ppm in all applications, it was seen that color difference and yellowing continued to be a problem. Considering the physical properties, which is one of the other negative results, the improvements in breaking and tearing strength were obtained compared to the untreated surface. While lower bending rigidity values were measured for all applications, surfaces had a softer handle after treatments. At the same time, the higher wrinkle angle values were achieved on the surfaces with an increase in concentration. It was determined that imidazoline gave the best wrinkle angle values among cross-linkers. The results showed that cross-linkers made a positive contribution to the wrinkle property of the viscose surface. 

Place, publisher, year, edition, pages
Gazi Universitesi, 2021
Keywords
Cross-linker, Physical properties, Softness, Viscose surface, Wrinkle recovery, Colorimetry, Crosslinking, Formaldehyde, Bending rigidity, Color difference, Cross linking agents, Free formaldehydes, Performance properties, Tear resistance, Tearing strength, Wrinkle recovery angle
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:hb:diva-26002 (URN)10.17341/gazimmfd.708351 (DOI)000626722500021 ()2-s2.0-85104253860 (Scopus ID)
Available from: 2021-07-08 Created: 2021-07-08 Last updated: 2021-10-21Bibliographically approved
Iyer, S., Behary, N., Guan, J., Orhan, M. & Nierstrasz, V. (2020). Color-changing intensified light-emitting multifunctional textiles via digital printing of biobased flavin. RSC Advances
Open this publication in new window or tab >>Color-changing intensified light-emitting multifunctional textiles via digital printing of biobased flavin
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2020 (English)In: RSC Advances, E-ISSN 2046-2069Article in journal (Refereed) Published
Abstract [en]

Flavin mononucleotide (biobased flavin), widely known as FMN, possesses intrinsic fluorescence characteristics. This study presents a sustainable approach for fabricating color-changing intensified light-emitting textiles using the natural compound FMN via digital printing technologies such as inkjet and chromojet. The FMN based ink formulation was prepared at 5 different concentrations using water and glycerol-based systems and printed on cotton duck white (CD), mercerized cotton (MC), and polyester (PET) textile woven samples. After characterizing the printing inks (viscosity and surface tension), the photophysical and physicochemical properties of the printed textiles were investigated using FTIR, UV/visible spectrophotometry, and fluorimetry. Furthermore, photodegradation properties were studied after irradiation under UV (370 nm) and visible (white) light. Two prominent absorption peaks were observed at around 370 nm and 450 nm on K/S spectral curves because of the functionalization of FMN on the textiles via digital printing along with the highest fluorescence intensities obtained for cotton textiles. Before light irradiation, the printed textiles exhibited greenish-yellow fluorescence at 535 nm for excitation at 370 nm. The fluorescence intensity varied as a function of the FMN concentration and the solvent system (water/glycerol). With 0.8 and 1% of FMN, the fluorescence of the printed textiles persisted even after prolonged light irradiation; however, the fluorescence color shifted from greenish-yellow color to turquoise blue then to white, with the fluorescence quantum efficiency values (φ) increasing from 0.1 to a value as high as 1. Photodegradation products of the FMN with varying fluorescence wavelengths and intensities would explain the results. Thus, a color-changing light-emitting fluorescent textile was obtained after prolonged light irradiation of textile samples printed using biobased flavin. Furthermore, multifunctional properties such as antibacterial properties against E. coli were observed only for the printed cotton textile while increased ultraviolet protection was observed for both cotton and polyester printed fabrics for the high concentration of FMN water-based and glycerol-based formulations. The evaluation of fluorescence properties using digital printing techniques aimed to provide more sustainable solutions, both in terms of minimum use of biobased dye and obtaining the maximum yield.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:hb:diva-24595 (URN)10.1039/D0RA05533F (DOI)000592897600056 ()2-s2.0-85097149872 (Scopus ID)
Available from: 2021-01-08 Created: 2021-01-08 Last updated: 2022-09-15Bibliographically approved
Orhan, M., Demirci, F., Kocer, H. B. & Nierstrasz, V. (2020). Supercritical carbon dioxide application using hydantoin acrylamide for biocidal functionalization of polyester. Journal of Supercritical Fluids, 165
Open this publication in new window or tab >>Supercritical carbon dioxide application using hydantoin acrylamide for biocidal functionalization of polyester
2020 (English)In: Journal of Supercritical Fluids, ISSN 0896-8446, E-ISSN 1872-8162, Vol. 165Article in journal (Refereed) Published
Abstract [en]

Biocidal functionalization in polyester fibers is a really tough challenge because of the lack of tethering groups. This study indicated supercritical carbon dioxide application using N-halamine would be an alternative solution for obtaining antibacterial function on the polyester surface. Firstly, N-(2-methyl 1-(4 methyl-2,5-dioxo-imidazolidin-4 yl)propan-2-yl)acrylamide was synthesized and applied to the polyester in supercritical carbon dioxide medium, at 120 degrees C, 30 MPa for different processing times. The addition of N-halamine on the surface significantly brought antibacterial activity against E. coli. The chlorine loadings showed that 6-h exposure time was critical to obtain sufficient antibacterial activity. This treatment caused a reasonable and tolerable loss in color and mechanical properties. But, the durability to abrasion, stability, and rechargeability of oxidative chlorine, and the durability of N-halamine on the surface were remarkably good. Conclusively, it can be available to work on polyester surfaces with resource-efficient and eco-friendly supercritical carbon dioxide technique for getting more functionalization and modification. (C) 2020 Elsevier B.V. All rights reserved.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Supercritical carbon dioxide (scCO(2)), N-halamine, Polyester, Antibacterial surface modification
National Category
Chemical Sciences
Identifiers
urn:nbn:se:hb:diva-24804 (URN)10.1016/j.supflu.2020.104986 (DOI)000558740300026 ()2-s2.0-85087878655 (Scopus ID)
Available from: 2021-01-25 Created: 2021-01-25 Last updated: 2021-10-21Bibliographically approved
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