Emine Dilara Koçak

Fully biobased composites combining renewable matrices and marine biomass-derived reinforcements offer a sustainable route toward multifunctional materials with tailored mechanical and acoustic properties. In this study, fully biobased composites were fabricated using a shellac/natural rubber latex matrix reinforced with marine biomass-derived Posidonia oceanica (PO) waste fibers. To improve interfacial compatibility, fibers were modified with succinic acid, a bio-based platform chemical, under ultrasonic treatment, providing a green and efficient surface functionalization strategy for fully biobased composites. Tensile testing showed that at 0.5% fiber content, elastic modulus (4.64 MPa), tensile strength (0.55 MPa), and elongation at break (255%) all improved compared with the neat matrix (3.59 MPa, 0.48 MPa, 196%). At 1%, stiffness further increased (4.72 MPa), but strength and ductility decreased due to fiber agglomeration, while 2% yielded maximum elongation (286%) despite reduced stiffness. Acoustic characterization revealed superior absorption at intermediate loadings, with coefficients of 0.41–0.44 at 6300 Hz, and a maximum of 0.52 at 2%. Micromechanical modeling performed via finite element analysis supported these findings, confirming stress concentration transitions from the matrix to the fiber-matrix interface with increasing fiber content and validating the experimental tensile results with less than 7% deviation. Among the investigated compositions, composites containing 0.5–1 wt % PO fibers exhibited the most balanced combination of stiffness, ductility, and acoustic absorption, demonstrating the potential of ultrasonically succinic acid-modified marine-derived fibers for developing fully biobased lightweight materials with multifunctional performance.

Aloe Vera Gel (AVG) is a product obtained from the leaf portion of the Barbadensis Miller plant and known for its wound-healing properties. PVA is a water-soluble, biologically disintegrated polymer. PLLA, the stereoisomer of the biodegradable polylactic acid obtained from corn, is a thermoplastic polymer and has properties such as strength and elasticity. In this study, in the first stage, PLLA polymer was converted into nanoweb form as a carrier layer. In the second stage, two-layer nanobiocomposites were produced by applying aloe vera (AVG)/PVA mixture on the existing PLLA nanoweb on the collector of the electrospinning device. The effects of the AVG addition of AVG/PVA/PLLA nanobiocomposite structures containing 0 %, 5 %, 10 %, and 20 % of AVG were examined by using instrumental methods such as viscosity, conductivity, pH, SEM, tensile strength, stretch %, delicacy, FT-IR, and XRD.As a result, the percentage of crystallization due to the AVG ratio in the mixtures increased and has been found to provide resistance to the structure. This feature will be the source for the formation of biocrheable resistant materials in future medical studies related to AVG.

In this study, okra gum polysaccharides derived from okra stem waste extract were utilized as a raw material for synthesizing hydrogel matrices. The polysaccharide‐rich okra gum was combined with gelatin to enhance the gelation properties of the resulting hydrogels. To assess and compare the self‐healing capabilities of the fabricated hydrogels, a natural and nontoxic crosslinking agent, succinic acid, was introduced into the hydrogel formulations at different ratios (5%, 7.5%, and 10% w / v ), imparting a dual network structure to the hydrogel matrices. Characterization of the synthesized hydrogels was conducted using scanning electron microscopy (SEM), Fourier‐transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) analyses, providing a comprehensive understanding of their structural and thermal properties. Furthermore, a series of three self‐healing assays, including gel block fusion tests, electrical conductivity assessments, and mechanical evaluations, were employed to evaluate the influence of succinic acid on the self‐healing efficacy of the okra–gelatin hydrogel composites. These investigations revealed promising outcomes, with the succinic acid–enhanced hydrogel formulation exhibiting a remarkable self‐healing ratio of 95% and an electrical conductivity recovery rate of 96.2%. Additionally, incorporating succinic acid in different proportions into the OK‐GUM‐GELSA hydrogel resulted in decreased swelling values. These findings underscore the significant potential of succinic acid as a crosslinking agent in enhancing the self‐healing properties of polysaccharide‐based hydrogel matrices, thereby paving the way for their promising applications in various fields, such as sustainable hydrogel sensors. These materials can provide environmentally friendly options for monitoring physiological and environmental changes, while their enhanced self‐healing properties contribute to more durable and reliable sensors for various electronic applications.

Natural dyeing of textile materials is gaining popularity all over the world since natural dyes are mostly eco-friendly, less toxic, and less allergenic as compared with synthetic dyes. Although synthetic dyes offer a broad range of color and color fastness and bright hues, they are nonbiodegradable and carcinogenic compounds and cause water pollution as well as waste disposal problems. This study presents the natural dyeing of cotton knitted fabric with three different structures using R. cordifolia root extract as a natural dye. Knitted fabrics with three different structures, interlock (350 g/m2), single jersey (145 g/m2) and rib (135 g/m2), were produced and dyed with madder (Rubia Cordifolia) in the presence of tannic acid as a mordant. The dyed samples were evaluated in terms of color measurement results (CIE L*,a*, b*, C*, h0, ∆E) and color fastness properties.

Bu çalışmada soya fasulyesi yağı esaslı, UV ışınları ile kürlenebilen bir oligomer sentezlenmiş ve bu oligomer liken partikülleri ile takviye edilerek kaplama formülasyonları hazırlanmıştır. Geliştirilen kaplama formülasyonları pamuk kumaşlar üzerine çevre dostu bir kaplama malzemesi olarak uygulanmış ve çevre dostu bir yöntemle (UV ışınları ile) kürlenmiştir. Liken partikülleri, kaplama malzemesi ile pamuk kumaş arasında bağlanma mekanizmasını geliştirmek ve sonucunda mekanik özellikleri iyileştirmek amacı ile kullanılmıştır. Liken ve oligomer arasındaki uyumu arttırmak için liken partiküllerinin yüzeyi çevre dostu iki yöntem ile (enzimatik ve UV ışınları) modifiye edilmiştir. Sentezlenen biyo-esaslı oligomer Fourier dönüşümlü kızılötesi (FTIR) ve proton nükleer manyetik rezonans (1H NMR) spektroskopileri, modifiye edilen liken partikülleri ise X-ışını kırınım difraktometresi (XRD) ile karakterize edilmiştir. Biyo-esaslı kaplama formülasyonları ile kaplanan pamuk kumaşlar ışık mikroskobu ile incelenmiş, mekanik özelliklerini tespit etmek amacı ile mukavemet ve sürtünme dayanımı testleri gerçekleştirilmiştir. Tüm bulgular değerlendirildiğinde biyo-esaslı kaplama malzemesi ile kaplanan pamuk kumaşların, geleneksel petrokimyasal kaplı dış mekân tekstillerine (tente, branda vb.) çevre dostu malzeme ve yöntemle üretilen bir alternatif olarak kullanılabileceği sonucuna ulaşılmıştır.