Influence of electrospun Nylon 6,6 nanofibrous mats on the interlaminar properties of Gr–epoxy composite laminates (original) (raw)
Related papers
Composite Structures, 2014
The necessity to produce modern composites with an acceptable impact resistance is an essential task in automobile and aerospace industry that needs to be satisfied. This capability is addressed by noteworthy energy absorption augmentation which is the most vital characteristic of such composite materials. In this paper, nanofibers are applied as interleaves to modify the delamination strength with a minimum rise in weight and thickness of the high-modulus polypropylene/epoxy composites. Nylon 6,6 nanofibers are produced by the electrospinning method. The distribution of nanofibers across the mats is examined by SEM. Innegra fabrics have been applied in composite layers production. The proper hand lay-up manufacturing of the laminates has been assured by the assistance of a hydraulic press. The energy absorption capacity at the onset of breakdown and impact resistance of the nanomodified and non-modified laminates were determined by quasistatic three-point flexural for the former and low-velocity impact tests for the latter. The obtained results were compared. The results showed a 6.2 and 16.9% increase in the energy absorption capacity of nanomodified laminates in quasi-static three-point flexural test and low-velocity impact tests, respectively. In addition, low-velocity impact tests revealed 16 and 26% improvement in maximum load capacity.
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.
Journal of Composite Materials, 2014
Nylon 6,6 nanofibers manufactured by means of electrospinning have been used to interleave Mode II fracture mechanics glass and carbon unidirectional fiber composite specimens. The aim of this work was to study the effect of the nanofibers materials in their ability to reinforce the interleave. Experimental testing was carried out on specimens with a nanofibrous mat interleaved into a delaminated interface. Specimens of 10, 16 and 18 layers were manufactured and tested. Results demonstrated that the effect of nanofibers was different between the two materials and that the fiber materials play an important role in the reinforcement mechanism of the nanofibers.
Composites Science and Technology, 2015
Electrospun thermoplastic nanofibres have a large potential for the interlaminar toughening of composite laminates. They can easily be placed in resin rich interlayers between reinforcing plies prior to laminate production and require no dispersion into the matrix resin. Although there are many expected benefits, the research on composite laminates enhanced with electrospun thermoplastic nanofibres is still very limited and a thorough understanding of the toughening mechanism is still missing. This article provides thorough insights into the micromechanisms that lead to the interlaminar toughening of carbon/epoxy composite laminates interleaved with electrospun polyamide nanofibrous veils. The main mechanism leading to a higher interlaminar fracture toughness, both under Mode I and Mode II loading conditions, was the bridging of (micro)cracks by PA nanofibres. The effectiveness of the nanofibre bridging toughening mechanism is dependent on a good load transfer to the nanofibres. Crack propagation under Mode II loading conditions resulted in much higher improvements than under Mode I loading due to an optimal loading of the nanofibres along their fibre direction in the plane of the nanofibrous veil. In Mode I crack propagation, however, the loading of the nanofibres is less optimal and was shown to be dependent on both the primary reinforcement fabric architecture, as well as on the presence of a carbon fibre bridging zone.
Polymer Composites, 2014
Nylon 6,6 electrospun nanofibrous membranes interleaved in "high performance" Carbon Fiber Reinforced Polymer (CFRP) laminates have been proposed as a means to provide a high threshold value to delamination on structural sites where composites are more prone to develop such failure. A model, highly crosslinked, thus inherently brittle, epoxy matrix was selected for its high Young's modulus and glass transition temperature exceeding 250 C. The influence of the Nylon 6,6 nanofibers on the curing behavior of the matrix and on the thermal and dynamic mechanical properties of the cured resin was investigated. These properties were related to the features of the epoxy resin and of the resin impregnated nanofibrous mat. Finally, the delamination behavior of the composite laminates interleaved with Nylon interleaves with different thicknesses was studied through Mode I delamination tests on Double Cantilever Beam (DCB) samples. The results show that the initial Mode I fracture toughness was increased up to about 50% by the presence of the thin mat interleaf. POLYM. COMPOS., 00:000-000, 2014.
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
A Review of Electrospun Nanofiber Interleaves for Interlaminar Toughening of Composite Laminates
polymers, 2023
Recently, polymeric nanofiber veils have gained lot of interest for various industrial and research applications. Embedding polymeric veils has proven to be one of the most effective ways to prevent delamination caused by the poor out-of-plane properties of composite laminates. The polymeric veils are introduced between plies of a composite laminate, and their targeted effects on delamination initiation and propagation have been widely studied. This paper presents an overview of the application of nanofiber polymeric veils as toughening interleaves in fiber-reinforced composite laminates. It presents a systematic comparative analysis and summary of attainable fracture toughness improvements based on electrospun veil materials. Both Mode I and Mode II tests are covered. Various popular veil materials and their modifications are considered. The toughening mechanisms introduced by polymeric veils are identified, listed, and analyzed. The numerical modeling of failure in Mode I and Mode II delamination is also discussed. This analytical review can be used as guidance for veil material selection, for estimation of the achievable toughening effect, for understanding the toughening mechanism introduced by veils, and for the numerical modeling of delamination.
The Effect of Nylon 6.6 Nanofiber Layers on Mechanical Properties of Epoxy
In this study mechanical properties of epoxy resin reinforced with different numbers of nanofiber layers of nylon 6.6 which produced with electrospinning method was investigated. Solution of 10 wt % of Nylon 6.6/ formic acid was used for electrospinning. The special molds were prepared to produce the laminated composite plates. Static tensile tests were performed, and the specimens were evaluated with respect to tensile strength and elongation at break, which are aspects of their basic mechanical properties.
Electrospun nanofibers as reinforcement for composite laminates materials - A Review
Composite Structures
In the last few decades nanofibers have been developed and introduced in a vast number of industrial and research applications. One of their most effective use is as interleaved reinforcement for composite laminate materials against delamination. Nanofibrous mats have the ideal morphology to be embedded between two plies of a laminate, and a vast and deep research has been carried out investigating their effect on the global behaviour of a composite laminate. This review is the first of its kind to date which presents a detailed state-ofthe-art on the effect of nanofibrous interleaves into composite laminates with focus on the mechanical performances and behaviours of nanomodified materials. A detailed description of the working mechanisms of the nanointerleave under different load cases is presented, and a comparative analysis between papers in literature will provide readers with a powerful tool to understand and use nanofibers for reinforcing purposes.
Impact Damage Resistance and Tolerance of Polymer Nanofiber Interleaved Composite Laminates
53rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference<BR>20th AIAA/ASME/AHS Adaptive Structures Conference<BR>14th AIAA, 2012
The primary limitation of fiber reinforced composite laminates is their poor interlaminar strength and fracture toughness that result in poor impact damage resistance and tolerance. A number of methods have been tried to address this limitation. These methods are limited by factors such as increase in cost, weight, or loss of in-plane properties. A promising approach which does not degrade the in-plane properties is interleaving. Thermoplastic particle interleaving has been applied to reinforce laminates but the primary concern of in-plane properties degradation has not been addressed. Polymer nano-fiber interleaving was investigated in this dissertation as an alternative approach to particle interleaving. The concept showed promise because of the very high surface area to volume ratio and high strain to fracture of the interleaving Nylon-66 nanofibers. The objectives of the work were to determine the relationship between the electric field and the polymer flow-rate, to improve the electrospinning process, to assess lowvelocity impact damage resistance and tolerance, and to compare the performance of the base laminate to the interleaved laminate. An electrospinning setup with a collector current management technique was developed to match the electric field to the flow-rate. Twenty-four ply quasi-isotropic base and interleaved AS4/3501-6 composite laminates were produced. Interleaving was achieved with 0.7 g/m 2 nano-fabric. The impacted