Electrospinning of cellulose nanofibers mat for laminated epoxy composite production (original) (raw)
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Nanomaterials
In this work, the effect of cellulose nanofiber (CNF) on the mechanical properties of long pineapple leaf fiber (PALF)-reinforced epoxy composites was investigated. The content of PALF was fixed at 20 wt.% and the CNF content was varied at 1, 3, and 5 wt.% of the epoxy matrix. The composites were prepared by hand lay-up method. Comparison was conducted between CNF-, PALF- and CNF–PALF-reinforced composites. It was found that the introduction of these small amounts of CNF into epoxy resin caused very small effects on flexural modulus and strength of neat epoxy. However, impact strength of epoxy with 1 wt.% CNF increased to about 115% that of neat epoxy, and, as the content of CNF increased to 3 and 5 wt.%, the impact strength decreased to that of neat epoxy. Observation of the fractured surface under electron microscope revealed the change in failure mechanism from a smooth surface to a much rougher surface. For epoxy containing 20 wt.% PALF, both flexural modulus and strength increa...
Cellulose nanofibers are one class of natural fibers that have resulted in structures with remarkable mechanical properties. In this study, the cellulose nanofibers are used as reinforcements in the forms of layered films in a bio-derived resin. Assessment of swelling behavior is performed together with an assessment of the tension and fracture behavior. Crack resistance behavior is compared to glass fiber systems and strategies for improving the fracture toughness of ''nanopaper'' based composites are discussed. Swelling tests indicate the need for constitutive and analysis approaches that account for the swelling response of the developed composites. Increased porosity is observed with higher reinforcement volumes leading to lower than expected mechanical properties. Techniques with higher consolidation pressures are required to improve consolidation processes.
Mechanical characterization of cellulose nanofiber and bio-based epoxy composite
Materials & Design, 2012
Cellulose nanofibers are one class of natural fibers that have resulted in structures with remarkable mechanical properties. In this study, the cellulose nanofibers are used as reinforcements in the forms of layered films in a bio-derived resin. Assessment of swelling behavior is performed together with an assessment of the tension and fracture behavior. Crack resistance behavior is compared to glass fiber systems and strategies for improving the fracture toughness of ''nanopaper'' based composites are discussed. Swelling tests indicate the need for constitutive and analysis approaches that account for the swelling response of the developed composites. Increased porosity is observed with higher reinforcement volumes leading to lower than expected mechanical properties. Techniques with higher consolidation pressures are required to improve consolidation processes.
Tensile properties and wear resistance of epoxy nanocomposites reinforced with cellulose nanofibers
Polymer Bulletin, 2017
Cellulose nanofibers (CNFs) were prepared from sugarcane bagasse and used as reinforcement in epoxy nanocomposites. To obtain CNFs, the cellulose was bleached with sodium chlorite, hydrothermally hydrolyzed with 5% w/v oxalic acid under pressure of 800 psi at 100°C in a microwave reactor, and homogenized using a mechanical homogenizer. The diameters of CNFs determined from field emission scanning electron microscope (FE-SEM) vary from 8 to 86 nm. The percentage crystallinity obtained from X-ray diffractometry is 62.8%. The epoxy was mixed with the prepared CNFs and cured at room temperature for 7 days. The effects of CNFs concentrations (0, 0.5, 1.0, 3.0, 5.0 and 10.0 wt%, dry basis) on the tensile properties and scratch resistance of the nanocomposites were investigated. Young's modulus and tensile strength increased with an increasing CNFs loading up to 3 wt %. Above that concentration the tensile elongation at break increased; this was at the rate faster than the modulus decreased. The instantaneous and healing scratch depths and thus viscoelastic recovery were determined using a micro-scratch tester. The percentage recovery values are higher for the nanocomposites than for the pure epoxy.
Journal of Reinforced Plastics and Composites, 2015
Nylon 6,6 nanofibers were interleaved in the mid-plan of glass fiber/epoxy matrix composite laminates for Mode I and II fracture mechanic tests. The present study investigates the effect of the nanofibers on the laminates' mechanical response. Results showed that Nylon 6,6 nanofibers improved specimen's fracture mechanic behaviour: the initial energy release rates G IC and G IIC increased 62% and 109% respectively when nanofibrous interlayer was used. Scanning Electron Microscope (SEM) micrographs showed that nanofiber bridging mechanism enhances performances of the nanomodified specimens, still able to link the layers when the matrix is broken.
Ultra-thin electrospun nanofibers for development of damage-tolerant composite laminates
Materials Today Chemistry, 2019
The present article overcomes existing challenges ahead of inter-laminar toughening of novel multifunctional fibre-reinforced polymer composites via development and embedment of highly stretched, ultra-thin electrospun thermoplastic nanofibers made of polyamide 6.6. The nanofibers have exhibited significant enhancement of the composite laminate's structural integrity with almost zero weight penalty via ensuring a smooth stress transfer throughout the plies and serving tailoring mechanical properties in desired directions, with no interference with geometric features e.g. thickness. The findings for 1.5 grams per square meter (gsm) electrospun nanofibers have demonstrated, on test coupons specimens, improvements up to 85% and 43% in peak load and crack opening displacement, respectively, with significant improvement (> 25%) and no sacrifice of fracture toughness at both initiation and propagation phases. The initial stiffness for the modified specimens was improved by nearly 150%. The enhancement is mainly due to nano-fibres contributing to the stiffness of the resin rich area at the crack tip adjacent to the Polytetrafluoroethylene (PTFE) film. Glass fibre-reinforced woven phenolic preimpregnated composite plies have been modified with the nano-fibres (each layer having an average thickness of <1 micron) at 0.5, 1.0, 1.5, 2.0 and 4.0 gsm, electrospun at room temperature on each ply, and manufactured via autoclave vacuum bagging process. Inter-laminar fracture toughness specimens were manufactured for Mode I (double cantilever beam, DCB) fracture tests. It was found that there is threshold for electrospun nanofibers density, at which an optimum performance is reached in modified composite Manuscript File
Süleyman Demirel Üniversitesi Fen Bilimleri Enstitüsü Dergisi
In this study mechanical and thermal properties of epoxy resin reinforced with different numbers of nanofiber layers which produced with electrospinning method was investigated. Solution of 10 wt% of polyacrylonitrile (PAN) in N,N-dimethylformamide (DMF) was used for electrospinning. The diameters of the obtained nanofibers were in the range of 380-420 nm. The average thickness of the produced nanofiber layer was about 200 µm. The special molds were prepared to produce the laminated composite plates. The tensile tests show that the using of nanofiber PAN layers increase the tensile force 34.54% and decrease the elongation 8.87% in comparison with neat epoxy. The fracture surfaces of the specimens were inspected by using optical and scanning electron microscopy (SEM). The thermal properties of the nanofiber layered composites were determined by thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis. It was observed that the glass transition temperature increased parallel to this as the number of PAN layers increased and rose up to 86ᵒC, while the thermal stability did not show much effect of PAN layers.
Thermal and dynamic mechanical properties of cellulose nanofibers reinforced epoxy composites
International journal of biological macromolecules, 2017
The current study presents about the effect of cellulose nanofibers (CNFs) filler on the thermal and dynamic mechanical analysis (DMA) of epoxy composites as a function of temperature. In this study hand lay-up method was used to fabricate CNF reinforced Epoxy nanocomposites with CNF loading of 0.5%, 0.75%, and 1% into epoxy resin. The obtained thermal and DMA results illustrates that thermal stability, char content, storage modulus (E'), loss modulus (E") and glass transition temperature (Tg) increases for all CNF/epoxy nanocomposites compared to the pure epoxy. Thermal results revealed that 0.75% offers superior resistance or stability towards heat compared to its counterparts. In addition, 0.75% CNF/epoxy nanocomposites confers highest value of storage modulus as compared to 0.5% and 1% filler loading. Hence, it is concluded that 0.75% CNFs loading is the minimal to enhance both thermal and dynamic mechanical properties of the epoxy composites and can be utilized for adv...
Characterization of Plant Nanofiber-Reinforced Epoxy Composites
BioResources, 2015
In the present study, oil palm empty fruit bunch (OPEFB) fibers were taken from a 25-year-old oil palm tree. The cellulosic nanofiber (CNF) was isolated from the OPEFB using a chemo-mechanical process and utilized as reinforcement in an epoxy matrix. Various CNF loading percentages (0 to 0.75%) were applied in the epoxy matrix to explore the potential of using OPEFB-CNF as reinforcement. The morphological, mechanical, physical, and thermal characteristics of the OPEFB nanofiber-reinforced epoxy composites were evaluated. Results showed that the 0.25% and 0.5% CNF loadings were homogenously distributed and well-dispersed in the composite matrix. Conversely, agglomeration was detected in the matrix with 0.75% CNF loading. Determination of the water absorption behavior of CNF-reinforced epoxy composites at various loadings revealed that the physical properties of the composites increased with reinforcement loading. Furthermore, the analyses of the mechanical and thermal properties of the CNF-reinforced composites revealed that the incorporation of OPEFB-CNF enhanced the mechanical performance and thermal stability up to 0.5% loading.