https://hdl.handle.net/20.500.12809/181 2026-07-10T14:09:38Z 2026-07-10T14:09:38Z Babahan, İlnur Bircan Altay, Çağlar Baysal, Ergun Kırım, Birsen Toker, Hilmi https://hdl.handle.net/20.500.12809/11239 2026-06-26T13:05:35Z 2026-01-01T00:00:00Z

The utilisation of turpentine and moss oil as epoxy hardeners for bio-based epoxy nanocomposite coatings Babahan, İlnur Bircan; Altay, Çağlar; Baysal, Ergun; Kırım, Birsen; Toker, Hilmi Despite the growing interest in bio-based epoxy systems, there remains a significant research gap in developing fully bio-derived curing agents that can replace conventional BPA-based epoxy hardeners while maintaining adequate mechanical and physical performance on wood substrates. The objective of this study was to investigate the potential of new bio-based, bisphenol A-free epoxide nanocomposite coatings for wood surfaces, as a replacement for commercially available coating containing bisphenol A. In addition, the surface properties of these coatings were evaluated. This study involves the use of environmentally friendly, bisphenol A-free, new bio-based epoxy coatings and their nanocomposite derivatives, in which both the resin and hardener are derived from natural sources. The study is original in its use of sustainable natural resources in the coatings industry, as well as in the development of cost effective and readily available systems compared to those derived from petroleum. Futhermore, this he research is is the first to employ moss oil and turpentine oil as hardeners in epoxy resin curing reactions. The results obtained with these two oils, which share a similar chemical structure, were compared. The study also investigates the effect of nanoparticles on the physical and mechanical properties of the bio-based coatings. In this study, novel bio-based epoxide nanocomposite coatings for wood surfaces were prepared using a tung oil-based epoxide resin, which was cured with moss and turpentine oil for the first time. Moss oil and turpentine oil were utilised as epoxy hardeners. The wood species selected for this investigation was Fagus orientalis (oriental beech). Furthermore, as prospective substitutes for bisphenol A, the characteristics of the new bio-based epoxide coatings, specifically the system obtained using moss oil and turpentine oil as hardening agent, were evaluated in relation to their nanocomposite derivatives doped with carbon nanoparticles (fullerene, carbon nanotubes, and graphene) for application on wooden substrates. Following the application of various coating materials to the wood surface, evaluations were conducted on the mechanical and physical properties of the wood. This included measurements of water absorption, t oven-dry density, and compression strength parallel to the grain of Fagus orientalis (oriental beech). The findings revealed that all test specimens showed oven-dry density values higher than those recorded for the control group. After the final absorption period, all coated specimens demonstrated a reduction in water absorption compared to the control.. Each coated specimen also exhibited a higher compression strength parallel to the grain than the control group. Consequently, it was established that the implementation of innovative bio-based nanocoatings has the potential to enhance the mechanical and physical properties of Fagus orientalis (oriental beech) wood.

2026-01-01T00:00:00Z Diler, Harun Kasal, Ali Kuşkun, Tolga Erdil, Yusuf Ziya Güray, Ersan https://hdl.handle.net/20.500.12809/11039 2023-10-25T11:42:48Z 2023-01-01T00:00:00Z

Strength Classification of Wooden Chairs under Cyclic Loads Based on an Experimental Study Diler, Harun; Kasal, Ali; Kuşkun, Tolga; Erdil, Yusuf Ziya; Güray, Ersan This study aimed to assess the cyclic load capacity of wooden chairs and subsequently categorize them based on their performance. A diverse selection of chair models was randomly procured from commercial markets. These chairs underwent performance testing, utilizing the cyclic stepped increasing loading method, with adherence to the standards set forth by the American Library Association Technology Reports (ALA). The study evaluated 315 chairs, encompassing 21 chair models. Each chair model underwent five replications of testing across three different loading directions. The resulting dataset of numerical values was subjected to statistical analyses, facilitating the categorization of chairs based on their strength under cyclic loads. Notably, the study revealed substantial variations in the load capacity among different chair models. As a consequence of this investigation, the study established acceptable design load thresholds. For instance, concerning front-to-back loading, it was determined that the chairs with cyclic load capacities ranging from 932 to 1449 N fell within the category of low-strength, between 1450 and 1968 N were classified as medium-strength (suitable for domestic use), and the chairs with cyclic load capacities exceeding 1968 N were considered to possess high strength (intended for hotel lobbies, restaurants, libraries, etc.). Similarly, for back-to-front loading performance, the study identified the chairs with cyclic load capacities between 625 and 895 N as low-strength, 896 and 1167 N as medium-strength, and the chairs with loads surpassing 1168 N as high-strength. The performance thresholds for side thrust loads were as follows: low-strength encompassed the cyclic load capacities ranging from 649 to 934 N, medium-strength spanned the cyclic load capacities between 935 and 1221 N, and high-strength entailed 1222 N and above. Notably, the classification devised in this study is closely aligned with the widely accepted and internationally recognized ALA specification. This strong consistency with global standards reinforces the reliability and applicability of the classification system developed in this research. In conclusion, this study enhances understanding of wooden chair strength performance and offers practical insights that lead to higher-quality products and improved consumer satisfaction. Its recommendations can potentially drive positive change within the industry and benefit manufacturers and consumers.

2023-01-01T00:00:00Z Göktaş, Osman Bozkaya, Yaşar Tahsin Yeniocak, Mehmet https://hdl.handle.net/20.500.12809/10944 2024-04-04T08:32:38Z 2023-01-01T00:00:00Z

The Use of Herbal Extracts in Lacquer Paint Coloring and Determination of Some Mechanical Resistance Properties on Wood-Based Surfaces Göktaş, Osman; Bozkaya, Yaşar Tahsin; Yeniocak, Mehmet The aim of this study was to determine the usability of selected natural dye extracts as environmentally friendly colorants that are used in painting of MDF based furniture and evaluate their resistance to scratch resistance, adhesion resistance, and surface hardness properties. In this study, the water-based lacquer coatings were prepared with natural dyes obtained from purple cabbage (Brassica oleracea), safflower (Carthamus tinctorius), Red beetroot (Beta vulgaris) and three synthetic paints that were black, blue and light blue as a comparison. Coated MDF test panels used for evaluation of performances of dyes to abiotic factors that are determined by mechanical tests such as scratch resistance, adhesion resistance, and surface hardness. As a result of the study, it has been observed that, except for scratch resistance, natural dyes perform as well as synthetic ones as alternative colorants in the lacquer coatings. Thus, natural and aesthetic raw materials that are environmentally friendly dyes can be used safely especially in children’s furniture and for wood-based products that are especially used indoors.

2023-01-01T00:00:00Z Özen, Ertan Ergun, Mehmet Emin Yıldırım, Nadir Dalkılıç, Berk https://hdl.handle.net/20.500.12809/10903 2023-08-23T08:09:35Z 2023-01-01T00:00:00Z

Mechanical and thermal properties of polyvinyl acetate foams reinforced with biopolymers Özen, Ertan; Ergun, Mehmet Emin; Yıldırım, Nadir; Dalkılıç, Berk The study developed and designed polyvinyl acetate (PVAc) foams using advanced freeze-drying technology, which exhibited good heat-insulating ability, flame retardancy, and mechanical properties. Different combinations of bleach kraft pulp, water-soluble chitosan, and zinc borate were used to reinforce the foams. The foams exhibited desirable compression and flexural properties, with compression strength and compression modulus ranging from 0.01 MPa to 0.08 MPa and 0.05 MPa to 0.29 MPa, respectively, while flexural strength and flexural modulus ranged from 0.12 MPa to 5.37 MPa and 9.86 MPa to 260,85 MPa, respectively. The use of zinc borate as a reinforcement resulted in improved thermal properties and reduced mass loss at 600°C by 20.69%. Thermal conductivity tests indicated that the foams had low thermal conductivity values ranging from 0.037 W/mK to 0.074 W/mK. The foams with zinc borate (60 g/L) and high molecular weight water-soluble chitosan (70 g/L) reinforcement exhibited high limiting oxygen index (LOI) of 28.72%. Overall, the results suggest that the PVAc foams could serve as a promising sustainable alternative in thermal insulation and construction fields.

2023-01-01T00:00:00Z