WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Article Investigating the Effects of Functionalized Single Wall Carbon Nanotubes on the Cure Behavior of a Carbon/Epoxy Prepreg System by an Optimized Parameter Approach(Wiley, 2025) Oz, Murat; Uz, Yusuf Can; Tanoglu, Gamze; Tanoglu, Metin; Barisik, MuratCarbon/Epoxy composite materials are used in a wide range of applications due to their superior performance. However, their properties are strongly related to cross-linking reactions occurring during the curing process, and a prior estimation of curing parameters is the key to manufacturing the desired material. This study builds a mathematical model to solve the inverse kinetic problem based on differential scanning calorimetry data and later presents its use in curing experiments. The method derived (Gamze-Murat-Neslisah (GMN) approach) determines the pre-exponential and activation energy of the curing process. Later, an extended experimental study was performed. Functionalized single-wall carbon nanotubes (F-SWCNTs) were prepared by oxidizing their surface with carboxyl to enhance the dispersion of the nanoparticulates. The epoxy resin systems were modified with 0.05%, 0.1%, and 0.2% wt. F-SWCNTs, which were impregnated on carbon fibers (CFs). The curing behavior was studied, cure kinetic parameters were determined, and the thermal behavior was characterized. Differential scanning calorimetry (DSC) data sets for CF/epoxy prepregs containing F-SWCNTs were used for the verification of the proposed method. It was found that the GMN approach is in good agreement with the experimentally measured data for all kinetic parameters. The addition of F-SWCNTs increased the material's curing efficiency as the CNTs enhanced heat transport in composites, reducing the activation energy. The results obtained from the GMN algorithm were also found in good agreement with the well-known Kissinger-Akahira-Sunose (KAS) and Kissinger methods, while the current GMN method revealed itself as an accurate algorithm to obtain the activation energy.Article Citation - WoS: 7Citation - Scopus: 7Improving Mechanical Behavior of Adhesively Bonded Composite Joints by Incorporating Reduced Graphene Oxide Added Polyamide 6,6 Electrospun Nanofibers(Elsevier Sci Ltd, 2024) Yeke, Melisa; Barisik, Murat; Tanoglu, Metin; Ulas, M. Erdal; Nuhogu, Kaan; Esenoglu, Gozde; Iris, M. ErdemAdhesive joining of fiber-reinforced polymer (FRP) composites requires adequate interface tailoring and careful surface preparation to obtain a strong bond between components. This study aimed to improve the mechanical performance of adhesively bonded unidirectional carbon fiber-based (CFRP) composite parts by modifying joint surfaces with graphene-added electrospun Polyamide 6,6 (PA66) nanofibers. Reduced graphene oxide (rGO) was dispersed at 10 % wt/v PA66 solution at three different concentrations below rGO saturation limits. Bead-free nanofibers with homogenous graphene distribution were obtained on a prepreg by electrospinning. Addition of up to 2 % rGO yielded complete dispersion through the nanofiber network while the higher values created local agglomerations. Surface wetting experiments showed conversion of slightly hydrophobic surfaces to complete hydrophilic with electrospun nanofiber coating and the lowest contact angle was obtained at 2 % wt/v rGO addition (26.18 degrees +/- 2.03 degrees). Composite plates were produced in a hot press keeping the modified prepregs on top. Plates with different surface treatments joined by secondary bonding using 3 plies of FM 300 K film adhesive. Mechanical properties of adhesively bonded composites were tested by Single lap joint and Charpy impact tests. We achieved an 18 % increase in shear strength and 31 % increase in impact strength by adding 2 % wt/v ratio rGO into PA66 electrospun nanofiber.