Search results for "Hybrid composites"

Wet electrospinning-aided self-assembly of multifunctional GO-CNT@PCL core-shell nanocomposites with spider leg bioinspired hierarchical architectures

2022

We report a fast route enabling the multiscale design of nanohybrid structures comprising a 3D fibrous network of polycaprolactone (PCL) wrapped by graphene oxide (GO) sheets onto which carbon nanotube (CNT) brushes are anchored. The method relies on electrospinning PCL solutions onto a suspension of GO and CNTs in ethanol. Self-assembly is due to electrostatic wrapping of GO sheets around PCL fibers and 7C-7C stacking between GO and CNTs. Hierarchical architecture and nanopatterned surface allow gathering the starting properties of PCL, GO and CNTs into lightweight (99% porosity) yet robust (1575% stiffness improvement), amphiphilic monoliths that can remove methylene blue and/or methyl or…

Assessment of performance degradation of hybrid flax-glass fiber reinforced epoxy composites during a salt spray fog/dry aging cycle

2022

The main goal of this paper is the evaluation of the performances reversibility of hybrid composites when they are dried after being aged in salt-fog environment. To this aim, epoxy composites reinforced with flax and glass fabrics respectively in the internal and external laminae were at first exposed to salt-fog (i.e., identified as wet phase) and then stored in controlled conditions (i.e., identified as dry phase). The flexural properties evolution of these composites as well as their water uptake and contact angle were monitored at varying time of both phases. The flexural strength and modulus of hybrid composites is 23.4% (17.9%) and 15.5% (12.9%) lower than unaged ones after 30 (15) d…

Benchmarking of strength models for unidirectional composites under longitudinal tension

2018

© 2018 Elsevier Ltd Several modelling approaches are available in the literature to predict longitudinal tensile failure of fibre-reinforced polymers. However, a systematic, blind and unbiased comparison between the predictions from the different models and against experimental data has never been performed. This paper presents a benchmarking exercise performed for three different models from the literature: (i) an analytical hierarchical scaling law for composite fibre bundles, (ii) direct numerical simulations of composite fibre bundles, and (iii) a multiscale finite-element simulation method. The results show that there are significant discrepancies between the predictions of the differe…

Flax–Glass Fiber Reinforced Hybrid Composites Exposed to a Salt-Fog/Dry Cycle: A Simplified Approach to Predict Their Performance Recovery

2023

Despite natural fibers gaining significant attention in recent decades, their limited performance and poor durability under humid environments cannot allow them to fully replace their synthetic counterparts as reinforcement for structural composites. In such a context, this paper aims to investigate how exposure to a humid/dry cycle affects the mechanical response of epoxy laminates reinforced with flax and glass fibers. In particular, the main goal is to assess the performance evolution of a glass–flax hybridized stacking sequence in comparison with the full glass and flax fiber reinforced composites. To this end, the investigated composites were first exposed to salt-fog for 15 or 30 days…

Durability of flax-basalt hybrid composites for marine applications

2015

The aim of the present work is to evaluate the influence of external layers of mat basalt on the durability behaviour and performances of flax/epoxy laminates. To this scope, long-term aging tests were performed to evaluate the durability of the two different laminates in critical environmental conditions. In particular, Flax composites were constituted by ten layers of bidirectional flax fabric whereas hybrid laminates (i.e. Flax-Basalt) were produced by replacing four external layers of bidirectional flax with four layers of basalt mat. Both laminates had a total average thickness equal to 3 mm. The samples were exposed to critical environmental conditions following the ASTM B 117 standar…

First lamina hybridization of high performance CFRP with Kevlar fibers: Effect on impact behavior and nondestructive evaluation

2022

The impact behavior of a carbon-Kevlar hybrid composite, widely used in sport car manufacturing, was evaluated. To highlight the hybridization effect, comparative analyses were performed with the basic CFRP laminate having the same lay-up. Tensile, bending and low velocity impact tests, followed by nondestructive inspections, highlighted that Kevlar first lamina hybridization leads to an increment in specific impact strength, up to 55%. To assess the most reliable technique to detect the impact damage, nondestructive evaluation was performed by pulsed thermography, phased array ultrasonic technique, computed tomography and digital radiography. Phased array ultrasonic technique can be consid…

Exceptional affinity of nanostructured organic-inorganic hybrid materials towards dioxygen: confinement effect of copper complexes

2007

We report the exceptional reactivity towards dioxygen of a nanostructured organic-inorganic hybrid material due to the confinement of copper cyclam within a silica matrix. The key step is the metalation reaction of the ligand, which can occur before or after xerogel formation through the sol-gel process. The incorporation of a Cu(II) center into the material after xerogel formation leads to a bridged Cu(I)/Cu(II) mixed-valence dinuclear species. This complex exhibits a very high affinity towards dioxygen, attributable to auto-organization of the active species in the solid. The remarkable properties of these copper complexes in the silica matrix demonstrate a high cooperative effect for O(2…

Experimental assessment of the improved properties during aging of flax/glass hybrid composite laminates for marine applications

2018

The investigation for natural fibers composites in terms of performance, durability, and environmental impact for structural applications in marine environments is a relevant challenge in scientific and industrial field. On this context, the aim of this work is to assess the durability and mechanical stability in severe environment of epoxy/glass–flax hybrid composites. For the sake of comparison, also full flax and glass epoxy composites were investigated. All samples were exposed to salt–fog environmental conditions up to 60 aging days. Wettability behavior during time was compared with water uptake evolution to assess water sensitivity of hybrid composite configurations. Moreover, quasi-…

ECS-3: A Crystalline Hybrid Organic-Inorganic Aluminosilicate with Open Porosity

2011

Novel hybrid polymer composites with graphene and MXene nano-reinforcements: computational analysis

2021

This paper presents a computational analysis on the mechanical and damage behavior of novel hybrid polymer composites with graphene and MXene nano-reinforcements targeted for flexible electronics and advanced high-strength structural applications with additional functions, such as real-time monitoring of structural integrity. Geometrical models of three-dimensional representative volume elements of various configurations were generated, and a computational model based on the micromechanical finite element method was developed and solved using an explicit dynamic solver. The influence of the geometrical orientation, aspect ratio, and volume fractions of the inclusions, as well as the interfa…