Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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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.Article Citation - WoS: 8Citation - Scopus: 8Improving Adhesive Behavior of Fiber Reinforced Composites by Incorporating Electrospun Polyamide-6,6 Nanofibers in Joining Region(SAGE Publications, 2022) Esenoğlu, Gözde; Barışık, Murat; Tanoğlu, Metin; Yeke, Melisa; Türkdoğan, Ceren; İplikçi, Hande; Martin, Seçkin; Nuhoğlu, Kaan; Aktaş, Engin; Dehneliler, Serkan; İriş, Mehmet ErdemAdhesive joining of fiber reinforced polymer (CFRP) composite components is demanded in various industrial applications. However, the joining locations frequently suffer from adhesive bond failure between adhesive and adherent. The aim of the present study is improving bonding behavior of adhesive joints by electrospun nanofiber coatings on the prepreg surfaces that have been used for composite manufacturing. Secondary bonding of woven and unidirectional CFRP parts was selected since this configuration is preferred commonly in aerospace practices. The optimum nanofiber coating with a low average fiber diameter and areal weight density is succeed by studying various solution concentrations and spinning durations of the polyamide-6.6 (PA 66) electrospinning. We obtained homogeneous and beadles nanofiber productions. As a result, an average diameter of 36.50 +/- 12 nm electrospun nanofibers were obtained and coated onto the prepreg surfaces. Prepreg systems with/without PA 66 nanofibers were hot pressed to fabricate the CFRP composite laminates. The single-lap shear test coupons were prepared from the fabricated laminates to examine the effects of PA 66 nanofibers on the mechanical properties of the joint region of the composites. The single-lap shear test results showed that the bonding strength is improved by about 40% with minimal adhesive use due to the presence of the electrospun nanofibers within the joint region. The optical and SEM images of fractured surfaces showed that nanofiber-coated joints exhibited a coherent failure while the bare surfaces underwent adhesive failure. The PA66 nanofibers created better coupling between the adhesive and the composite surface by increasing the surface area and roughness. As a result, electrospun nanofibers turned adhesive failure into cohesive and enhanced the adhesion performance composite joints substantially.
