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Öğe Design and Characterization of Polyvinyl Alcohol/Kappa-Carrageenan Pickering Emulsion Biocomposite Films for Potential Wound Care Applications(Wiley, 2024) Yesilyurt, Aysenur; Mayakrishnan, Gopiraman; Parin, Ugur; Kim, Ick Soo; Parin, Fatma Nur; Ullah, AzeemThis study aimed to develop polyvinyl alcohol (PVA) and kappa-carrageenan (kappa CA) biocomposite films using a Pickering emulsion technique for wound care applications. Juniper essential oil and modified sepiolite were incorporated to enhance functionality, with films prepared via solvent casting and characterized for structural, thermal, and mechanical properties. The PCOS-2 film exhibited the highest mechanical performance, with Young's modulus of 6.25 +/- 1.3 MPa, tensile strength of 5.65 +/- 1.7 MPa, and elongation at break of 608.96% +/- 72.8%. Antibacterial assays showed inhibition zones of 9 and 10 mm against Staphylococcus aureus and Escherichia coli, respectively, for the PCOS-2 film, while antioxidant activity reached 63% DPPH radical scavenging after 12 h. Additionally, porosity and hydrophilicity were enhanced, as indicated by contact angles of 55 degrees for the control film and 71.2 degrees for PCOS-2. These results underscore the potential of PVA/kappa CA biocomposite films as sustainable and bioactive wound dressings, combining mechanical resilience, bioactivity, and environmental compatibility, with future efforts focused on optimizing antibacterial efficacy against gram-negative bacteria and clinical validation.Öğe Development and Characterization of LDPE/Vermiculite Composites: Effects on Mechanical, Thermal, and Morphological Properties(Wiley-V C H Verlag Gmbh, 2025) Yesilyurt, AysenurIn this study, vermiculite (VMT), a naturally occurring layered silicate, was incorporated into a low-density polyethylene (LDPE) matrix at loading levels of 5 wt%, 7.5 wt%, 10 wt%, and 15 wt%. The composites were prepared by melt blending using a twin-screw extruder followed by injection molding. Thermal, mechanical, morphological and structural characterizations were conducted through thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), tensile and flexural tests, Izod notched impact testing, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). TGA results indicated an increase in thermal degradation onset temperature from 357 degrees C (neat LDPE) to 389 degrees C (15 wt% VMT), confirming enhanced thermal stability. DSC analysis showed a slight reduction in crystallinity with increasing VMT content. The tensile and flexural moduli were improved proportionally with VMT loading, suggesting a stiffening effect, while elongation at break and impact resistance decreased, implying reduced ductility. SEM observations revealed good filler dispersion at low concentrations, but particle agglomeration and interfacial voids became evident at higher loadings. FTIR spectra confirmed the presence of VMT without any significant chemical interaction with the LDPE backbone. Overall, the incorporation of VMT enhances the rigidity and thermal resistance of LDPE composites, making them promising candidates for structural applications where dimensional stability and thermal performance are critical.Öğe Development and Characterization of PVA/KGM-Based Bioactive Films Incorporating Natural Extracts and Thyme Oil(Mdpi, 2025) Yesilyurt, AysenurThis study focused on the development and characterization of polyvinyl alcohol (PVA)- and konjac glucomannan (KGM)-based composite films enriched with natural bioactive additives. A PK (PVA/KGM) matrix with the optimum tensile strength was selected, and five film formulations were prepared by incorporating Aronia melanocarpa extract (AME), red dragon fruit extract (DFE), and thyme essential oil (TEO). TEO was also introduced via a Pickering emulsion (PE) technique. The total phenolic content (TPC) and free radical scavenging activity (FRSA) of extracts and films were determined, where AME exhibited the highest antioxidant activity (TPC: 243 mg GAE/g; FRSA: 81.7%). The additive-free PK film displayed limited antioxidant activity (18%), while antioxidant capacity significantly improved with extract and EO incorporation. The PK-A film (AME-added) demonstrated the highest tensile strength and lowest water vapor permeability, supported by increased local crystallinity detected in XRD. Color analysis indicated dominant red-violet tones in AME films and greenish-yellow tones in DFE films. FTIR confirmed that no new chemical bonds were formed between active compounds and the polymer matrix. DSC thermograms revealed consistent melting peaks (similar to 150 degrees C) for all films, while Tg varied from 37 to 73 degrees C depending on additive type, reflecting plasticization effects of extracts and the counterbalancing effect of essential oil. The most hydrophobic (76.8 degrees) and opaque sample was PK-ADO, prepared via the PE technique. Overall, natural extracts improved the structural, thermal, barrier, and antioxidant properties of PK films.Öğe Development of PVA-Psyllium Husk Meshes via Emulsion Electrospinning: Preparation, Characterization, and Antibacterial Activity(Mdpi, 2022) Parin, Fatma Nur; Ullah, Azeem; Yesilyurt, Aysenur; Parin, Ugur; Haider, Md Kaiser; Kharaghani, DavoodIn this study, polyvinyl alcohol (PVA) and psyllium husk (PSH)/D-limonene electrospun meshes were produced by emulsion electrospinning for use as substrates to prevent the growth of bacteria. D-limonene and modified microcrystalline cellulose (mMCC) were preferred as antibacterial agents. SEM micrographs showed that PVA-PSH electrospun mesh with a 4% amount of D-limonene has the best average fiber distribution with 298.38 +/- 62.8 nm. Moreover, the fiber morphology disrupts with the addition of 6% D-limonene. FT-IR spectroscopy was used to analyze the chemical structure between matrix-antibacterial agents (mMCC and D-limonene). Although there were some partial physical interactions in the FT-IR spectrum, no chemical reactions were seen between the matrixes and the antibacterial agents. The thermal properties of the meshes were determined using thermal gravimetric analysis (TGA). The thermal stability of the samples increased with the addition of mMCC. Further, the PVA-PSH-mMCC mesh had the highest value of contact angle (81 degrees +/- 4.05). The antibacterial activity of functional meshes against Gram (-) (Escherichia coli, Pseudomonas aeruginosa) and Gram (+) bacteria (Staphylococcus aureus) was specified based on a zone inhibition test. PPMD6 meshes had the highest antibacterial results with 21 mm, 16 mm, and 15 mm against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, respectively. While increasing the amount of D-limonene enhanced the antibacterial activity, it significantly decreased the amount of release in cases of excess D-limonene amount. Due to good fiber morphology, the highest D-limonene release value (83.1%) was observed in PPMD4 functional meshes. The developed functional meshes can be utilized as wound dressing material based on our data.Öğe Enhancing sound transmission loss of polyurethane foams using waste soda glass filler(2024) Yesilyurt, AysenurSound transmission mechanisms and sound transmission losses are of great importance in providing acoustic comfort. Research has focused on developing materials and structures that will reduce sound transmission loss. The increasing amount of waste disrupts the ecological balance; this situation brings about global warming, air and soil pollution. These environmental effects negatively affect the lives of all living things, especially humans, and also harm the economy. Combating global pollution has become one of the primary goals of scientists. Recycling provides significant economic benefits as well as protecting both human health and natural resources. In this study, polyurethane foams used in the automotive industry and many other areas were produced by adding waste soda glass powder at various rates while keeping the isocyanate/polyol ratio constant. The durability of the produced foams was tested by apparent density measurement, wettability by contact angle analysis, organic bond structures by FT-IR spectroscopy and acoustic properties by sound transmission loss analysis. It was determined that soda glass powder did not react with the foams and that the produced foams exhibited hydrophobic properties. The acoustic properties of the filler foams were higher than the neat foam in almost the entire frequency range (65-6300 Hz). The sample coded PU-SG4 is the sample that exhibits the best acoustic properties by reaching 9.28 dB, 9.10 dB and 13.48 dB values in the low, medium and high frequency regions, respectively. In the high frequency range region, all of the soda glass added foam composites reached a sound transmission loss of over 13 dB.Öğe Evaluation of Properties of Polypropylene Matrix Composites Reinforced With Perlite, Expanded Perlite, Silanized Expanded Perlite, and Talc Fillers(Wiley, 2025) Yesilyurt, Aysenur; Uysal, NaciImproving the mechanical and thermal performance of polypropylene (PP) composites is essential to meet the demanding requirements of contemporary automotive, construction, and electrical-engineering applications. To address this, PP matrix composites were developed using natural and environmentally friendly fillers such as speech, perlite, expanded perlite, and silanized expanded perlite, and their physical, mechanical, morphological, and thermal properties were investigated. Composites were prepared using a twin-screw extruder with 5%, 10%, and 20% (w/w) fillers, and additives were used as PP reference samples. The samples were evaluated through density measurements, FTIR spectroscopy, color analysis, melt flow index, tensile and flexural strength testing, impact resistance, scanning electron microscopy, thermogravimetric analysis, and heat deflection temperature (HDT) testing. The results showed significant changes in the properties of the filler material used and structural composites. Thermal properties of hybrid composites showed improvement compared to neat PP for all types and ratios. The HDT values of the composites are similar to each other and to that of pure PP. The flexural strength and tensile strength values of neat PP are 22.1 and 16.2 MPa, while the flexural and tensile values for all ratios of four different inorganic additives resulted in higher values. The flexural strength of PP-P20 (20% perlite additive) composite is increased by 43%, and the tensile strength increased by 29% compared to pure PP. As expected, the values of the composites were higher compared to pure PP. The melt flow index values decreased for the additives, except for the perlite additive. The index of the additive ratios used belongs to the higher values compared to PP. The innovations obtained show that these additive ratios are effective in the development of PP matrix composites in high-performance range applications as low selection and environmentally friendly options.Öğe Mechanical, Thermal, and Sound Properties of Bamboo-Powder-Filled Polyurethane Composites(Wiley-V C H Verlag Gmbh, 2024) Yesilyurt, Aysenur; Parin, Fatma Nur; Uysal, NaciBamboo, which is called green gold because of its sustainability characteristics, has many wonderful properties that make it environmentally friendly. In this study, polyurethane (PU) composites used in the automotive industry were produced by adding different amounts of bamboo powders (1, 2.5, 5, 7.5, 10 and 15%, w/v) to PU foams. In this regard, density, light and stereomicroscopic analysis, thermal conductivity, spectroscopic analysis, and mechanical (compression) test have been performed. Further, sound absorption analysis and contact angle analysis have been carried out. Optical and stereomicroscopes showed average pore sizes with range of 258-482 mu m. As the bamboo powder increased, the contact angle values decreased from 129 degrees to 88 degrees. Compression force deflection values of the samples declined from 1850 to 360 g/cm2. Similar to the mechanical properties, the thermal conductivities of the PU foams decreased. However, in regards to FT-IR, no chemical reactions were observed between PU matrix and bamboo powder. The sound absorption test results showed that bamboo powder filled PU foams are sound absorption materials and that rigid PU foam with 2.5% (w/v) (PU-2.5) bamboo powder sample had better sound absorption properties than the bamboo-powder-unfilled rigid PU foam (PU-0), with an average sound absorption coefficient value of 0.86 at 6300 Hz and 0.71 in the range of 1600-6300 Hz. Bamboo powder, called green gold, has been used in the production of polyurethane foams that are used in many sectors. Thermal conductivity, sound absorption, mechanical strength, wettability, pore size, and sponge apparent density properties of polyurethane foams were examined depending on the proportions of bamboo powder. In line with the data obtained, it has been observed that bamboo#x02010;powder#x02010;filled polyurethane foams can be used as sound insulation materials and thermal insulation materials. imageÖğe PVA/Inulin-Based Sustainable Films Reinforced with Pickering Emulsion of Niaouli Essential Oil for Potential Wound Healing Applications(Mdpi, 2023) Parin, Fatma Nur; El-Ghazali, Sofia; Yesilyurt, Aysenur; Parin, Ugur; Ullah, Azeem; Khatri, Muzamil; Kim, Ick SooIn this study, sustainable water-based films were produced via the solvent-casting method. Petroleum-free-based polyvinyl alcohol (PVA) and carbohydrate-based inulin (INL) were used as matrices. Vegetable-waste pumpkin powder was used in the study because of its sustainability and antibacterial properties. Pickering emulsions were prepared using beta-cyclodextrin. The influence of the different ratios of the beta-cyclodextrin/niaouli essential oil (beta-CD/NEO) inclusion complex (such as 1:1, 1:3, and 1:5) on the morphological (SEM), thermal (TGA), physical (FT-IR), wettability (contact angle), and mechanical (tensile test) characteristics of PVA/inulin films were investigated. Moreover, the antibacterial activities against the Gram (-) (Escherichia coli and Pseudomonas aeruginosa) and Gram (+) (Staphylococcus aureus) bacteria of the obtained films were studied. From the morphological analysis, good emulsion stability and porosity were obtained in the Pickering films with the highest oil content, while instability was observed in the Pickering films with the lowest concentration of oil content. Thermal and spectroscopic analysis indicated there was no significant difference between the Pickering emulsion films and neat films. With the addition of Pickering emulsions, the tensile stress values decreased from 7.3 +/- 1.9 MPa to 3.3 +/- 0.2. According to the antibacterial efficiency results, films containing pumpkin powder and Pickering emulsion films containing both pumpkin powder and a ratio of 1:1 (beta-CD/NEO) did not have an antibacterial effect, while Pickering emulsion films with a ratio of (beta-CD/NEO) 1:3 and 1:5 showed an antibacterial effect against Escherichia coli, with a zone diameter of 12 cm and 17 cm, respectively. Among the samples, the films with ratio of (beta-CD/NEO) 1:5 had the highest antioxidant capacity, as assessed by DPPH radical scavenging at 12 h intervals. Further, none of the samples showed any cytotoxic effects the according to LDH and WST-1 cytotoxicity analysis for the NIH3T3 cell line. Ultimately, it is expected that these films are completely bio-based and may be potential candidates for use in wound healing applications.Öğe PVA/WHEY PROTEIN NANOFIBER-COATED PP MELT BLOWN INTEGRATED WITH PICKERING EMULSION OF CITRAL STABILIZED FOR POTENTIAL MEDICAL APPLICATIONS(2024) Parın, Fatma Nur; Yesilyurt, Aysenur; Parın, UğurAs an antibacterial agent with pleasant fragrance, citral (CIT) indicates hydrophobic character, and therefore has low water solubility. In this study, Pickering emulsions were formed and polyvinyl alcohol (PVA)/whey protein hydrophilic nanofibers were coated on PP melt blown non-woven surfaces by electrospinning method. In this context, hydrophobic citral essential oil is stabilized with ?-cyclodextrin (?-CD) in the electrospinning process. PVA and whey protein polymer blend were used as nanofiber matrices. The morphological, physical, and thermal properties of the ?-CD/citral complexes were investigated in PVA/whey protein nanofiber-coated PP non-wovens at various ?-CD levels (1:2, 1:4 and 1:6). Furthermore, zone inhibition procedure was performed to evaluate antibacterial activity of the samples against Gram (+) (Staphylococcus aureus ATCC® 25923) and Gram (-) (Escherichia coli ATCC® 25922, and Pseudomonas aeruginosa ATCC® 27853) bacteria. The morphology of fibers showed that all obtained nanofiber-coated PP surfaces were in the range with 216 - 330 nm average fiber diameter. Fourier Transform Infrared (FT-IR) and thermal gravimetric analysis (TGA) thermograms revealed that citrals were successfully integrated into the bio-based nanofibers. As the amount of citral increased (i.e., the ?-CD/citral increased), the thermal resistance of bio-based nanofiber coated PP surfaces increased. Antibacterial activity indicated the citral-loaded nanofiber-coated PP surfaces were most effective against Escherichia coli, while none of the samples have antibacterial activity against Pseudomonas aeruginosa. Overall, the results displayed that the fabricated PVA/whey protein nanofiber-coated PP samples integrated with Pickering emulsion of citral stabilized have promising wound dressing applications.
