Browsing by Author "Ahmetli, Gulnare"

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Exploring the Influence of Various Filler Modification Techniques on the Biocomposites Properties Derived From Lignocellulosic Hazelnut Waste Shells
(Elsevier, 2025) Ahmetli, Gulnare; Kocaman, Suheyla; Yuksel, Busra Donmez; Ulusoy, Pinar; Musayev, Nijat
Biocomposites exhibit a wide range of properties and can compete with non-biodegradable polymers across various industrial fields. This study presented research results using hazelnut shell waste (HShW) as a biofiller in an epoxy matrix. HShW was modified using sodium hydroxide and several acids, including ethylenediaminetetraacetic (EDTA), acetic (AA), acrylic (AcA), and linoleic (LA). The modification process increased cellulose content, while lignin and hemicellulose contents decreased. This study explored the effects of filler content and modification type on the composites' mechanical, thermal, dynamic mechanical, water sorption, chemical resistance, and hygrothermal aging properties. The distinct X-ray diffraction (XRD) peaks around 22 degrees confirm that Cellulose I retains its original crystal structure within the composites. All modifications improved the tensile strength of the biocomposites, particularly at 20-30 wt%, ranging from 4.65 % to 53.49 %. The LA-HShW composites displayed the highest tensile strength (101-132 MPa), thermal stability, and glass transition temperature (Tg) values of 101.1 degrees C (DMA) and 66.4 degrees C (DSC). The AcA-and LA-modified HShW composites exhibited the lowest mass loss rate at 379.2 degrees C among the composite materials. All composites demonstrated greater resistance to alkali and acids such as hydrochloric and sulfuric, while showing lower resistance to acetone. In addition, hygrothermal aging increased moisture uptake (2.45-5.68 %) in biocomposites and reduced Tg values. A decrease in the Tg values of DMA and DSC was between 4.80 and 18.71 % and 7.01-18.29 %, respectively. The 20 wt% LA-HShW composite demonstrated significantly greater stability to aging, exhibiting the highest storage modulus (0.85 GPa), loss modulus (0.06 GPa), and DSC Tg (58.2 degrees C) compared to the other composites.
Thermochemical Treatment of Waste Polypropylene (PP) Using Marble Sludge as Catalyst-II: Evaluation of Chemicals Recovery Potential From Pyrolytic Fluids
(Sage Publications Ltd, 2025) Kalem, Merve; Ozgan Kurt, Afra; Goktepeli, Gamze; Onen, Vildan; Ahmetli, Gulnare; Yel, Esra
In this study, waste polypropylene (PP) was pyrolysed together with marble processing industry effluents physicochemical treatment sludge (named as K1) catalyst, and the valuable component recovery and usage potential from resulting liquid and gaseous products were investigated. In the fixed bed pyrolysis reactor under inert conditions with N2 gas, the studied experimental variables were temperature and mixing ratio. The resultant liquid and gaseous fractions were characterized via GC-MS, Fourier transform infrared, thermogravimetric analysis and calorific value analyses. Liquid products contain predominantly paraffinic and olefinic, but minor aromatic hydrocarbons (HCs) and also minor amounts of oxygenated compounds with 20-30% K1 catalyst. Heating values of the liquid products were around 10 kcal.g-1. The gas products predominantly contain alkanes, alkenes and aromatic HC compounds with economic value such as benzene isotridecanol, heptanol, ketone and terpene. Ca and Mg carbonate structure of K1 catalyst increased the compound diversity in the pyrolysis gas, especially in the aliphatic groups. The detected low C number alkane compounds were pentane, heptane, cyclohexane and high C number long-chain n-alkane aliphatic compounds were docosane, hexacosane and hexatriacontane. The recoverable compounds are economically and environmentally important as they can be used in many industries such as cleaning, cosmetics, pharmacology and petrochemistry as feedstock. The proposed pyrolysis provided symbiotic solution to these two types of wastes and the resultant products of this application have potential for energy and compound recovery. Recovery methods can be further studied.