Showing papers on "Epoxy published in 2013"
TL;DR: In this paper, the effect of dispersion state of graphene on mechanical properties of graphene/epoxy composites was investigated, and it was found that the composites with highly dispersed RGO showed higher glass transition temperature (T g ) and strength than those with poorly-dispersed RGO.
928 citations
TL;DR: A novel approach is presented to disperse non-oxidized graphene flakes with non-covalent functionalization of 1-pyrenebutyric acid and to fabricate nanocomposites with outstanding thermal conductivity and mechanical properties.
Abstract: Homogeneous distribution of graphene flakes in a polymer matrix, still preserving intrinsic material properties, is key to successful composite applications. A novel approach is presented to disperse non-oxidized graphene flakes with non-covalent functionalization of 1-pyrenebutyric acid and to fabricate nanocomposites with outstanding thermal conductivity (∼1.53 W/mK) and mechanical properties (∼1.03 GPa).
598 citations
TL;DR: A short background on the research work carried out on epoxy clay nanocomposites can be found in this paper, where the authors highlight the morphology and the final mechanical, thermal and barrier properties of the nanocomposition.
Abstract: The review renders a short background on the research work carried out on epoxy clay nanocomposites Clays are one of the ideal nano reinforcements for polymers because of their high intercalation chemistry and aspect ratio Epoxy clay nanocomposites are finding vast applications in various industries like aerospace, defense, automobile, etc The physical and chemical properties of the epoxy systems are influenced by the processing techniques, clay modifier and curing agents used for the preparation of nanocomposites The clay morphology (intercalation/exfoliation) of the nanocomposites is also depended on the above parameters So the emphasis of the present work is to highlight these parameters on morphology and the final mechanical, thermal and barrier properties of the nanocomposites The proposed applications of the epoxy clay nanocomposites are also discussed
562 citations
TL;DR: In this article, an ideal dielectric thermally conductive epoxy nanocomposite is successfully fabricated using polyhedral oligosilsesquioxane (POSS) functionalized boron nitride nanotubes (BNNTs) as fillers.
Abstract: Dielectric polymer composites with high thermal conductivity are very promising for microelectronic packaging and thermal management application in new energy systems such as solar cells and light emitting diodes (LEDs). However, a well-known paradox is that conventional composites with high thermal conductivity usually suffer from the high dielectric constant and high dielectric loss, while on the other hand, composite materials with excellent dielectric properties usually possess low thermal conductivity. In this work, an ideal dielectric thermally conductive epoxy nanocomposite is successfully fabricated using polyhedral oligosilsesquioxane (POSS) functionalized boron nitride nanotubes (BNNTs) as fillers. The nanocomposites with 30 wt% fraction of POSS modified BNNTs exhibit much lower dielectric constant, dielectric loss tangent, and coefficient of thermal expansion in comparison with the pure epoxy resin. As an example, below 100 Hz, the dielectric loss of the nanocomposites with 20 and 30 wt% BNNTs is reduced by one order of magnitude in comparison with the pure epoxy resin. Moreover, the nanocomposites show a dramatic thermal conductivity enhancement of 1360% in comparison with the pristine epoxy resin at a BNNT loading fraction of 30 wt%. The merits of the designed composites are suggested to originate from the excellent intrinsic properties of embedded BNNTs, effective surface modification by POSS molecules, and carefully developed composite preparation methods.
519 citations
TL;DR: In this article, the mechanical and thermal properties of raw jute and banana fiber reinforced epoxy hybrid composites were investigated and compared and it was shown that the addition of banana fiber in jute/epoxy composites of up to 50% by weight results in increasing the mechanical properties and decreasing the moisture absorption property.
Abstract: The aim of the present study is to investigate and compare the mechanical and thermal properties of raw jute and banana fiber reinforced epoxy hybrid composites. To improve the mechanical properties, jute fiber was hybridized with banana fiber. The jute and banana fibers were prepared with various weight ratios (100/0, 75/25, 50/50, 25/75 and 0/100) and then incorporated into the epoxy matrix by moulding technique to form composites. The tensile, flexural, impact, thermal and water absorption tests were carried out using hybrid composite samples. This study shows that addition of banana fiber in jute/epoxy composites of up to 50% by weight results in increasing the mechanical and thermal properties and decreasing the moisture absorption property. Morphological analysis was carried out to observe fracture behavior and fiber pull-out of the samples using scanning electron microscope.
418 citations
TL;DR: In this article, the embedding of carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) into pristine epoxy endows optimum dispersion of CNTs and GNPs as well as better interfacial adhesion between the carbon fillers and matrix, which results in a significant improvement in load transfer effectiveness.
382 citations
TL;DR: In this article, the tensile properties of hybrid composites were found to increase substantially with increasing jute fibres loading as compared to oil palm-epoxy composite, and the overall use of hybrid system was found to be effective in increasing tensile and dynamic mechanical properties of the oil palm/polyurethane composite probably due to the enhanced fibre/matrix interface bonding.
Abstract: Hybrid composites prepared by hand lay-up technique by reinforcing jute and oil palm fibres with epoxy matrix. The tensile properties of hybrid composites were found to increase substantially with increasing jute fibres loading as compared to oil palm–epoxy composite. The nature of fibre/matrix interface was examined through scanning electron microscopy of tensile fracture samples. Addition of jute fibres to oil palm composite increases the storage modulus while damping factor shifts towards higher temperature region. Cole–Cole analysis was made to understand the phase behaviour of the composite samples. The hybrid composite with oil palm:jute (1:4) showed maximum damping behaviour and highest tensile properties. The overall use of hybrid system was found to be effective in increasing tensile and dynamic mechanical properties of the oil palm–epoxy composite probably due to the enhanced fibre/matrix interface bonding. The potential applications of the oil palm based hybrid composites in automobiles and building industry are going to increase in near future.
370 citations
TL;DR: Hardis et al. as mentioned in this paper describe the characterization and monitoring of an Epoxy Resin for thick composite structures. But they do not discuss the properties of the epoxy resins.
Abstract: R. Hardis, J. Jessop, F. E. Peters, M. R. Kessler. Cure Kinetics Characterization and Monitoring of an Epoxy Resin for Thick Composite Structures, Composites Part A: Applied Science and Manufacturing, 2013, 49, 100-108. doi:10.1016/j.compositesa.2013.01.021.
331 citations
TL;DR: In this article, the effects of 3-aminopropyltriethoxysilane (APTES) functionalized silica nanoparticles attached graphene oxide (ATGO) in epoxy were investigated Fourier transform infrared and X-ray photoelectron spectroscopy analysis confirmed chemical functionalization and partial reduction of GO during the functionalization.
322 citations
TL;DR: In this article, a facile surfactant-assisted process was used to improve the dispersion and exfoliation level of highly dispersed graphene in epoxy composites, resulting in increased tensile properties compared with those without surface modification.
297 citations
TL;DR: In this paper, the influence of graphite nano-platelets (GNPs) on the electrical and thermal conductivity, fracture toughness and storage modulus of the nano-composite was investigated.
TL;DR: In this paper, the nanoindentation was used to determine modulus and creep compliance for GNP/epoxy composites and the GNP aspect ratio was confirmed to be similar to that of the as-received material by using the percolation threshold measured from electrical resistivity measurements.
Abstract: Because of their high-specific stiffness, carbon-filled epoxy composites can be used in structural components in fixed-wing aircraft. Graphene nanoplatelets (GNPs) are short stacks of individual layers of graphite that are a newly developed, lower cost material that often increases the composite tensile modulus. In this work, researchers fabricated neat epoxy (EPON 862 with Curing Agent W) and 1–6 wt % GNP in epoxy composites. The cure cycle used for this aerospace epoxy resin was 2 h at 121°C followed by 2 h at 177°C. These materials were tested for tensile properties using typical macroscopic measurements. Nanoindentation was also used to determine modulus and creep compliance. These macroscopic results showed that the tensile modulus increased from 2.72 GPa for the neat epoxy to 3.36 GPa for 6 wt % (3.7 vol %) GNP in epoxy composite. The modulus results from nanoindentation followed this same trend. For loadings from 10 to 45 mN, the creep compliance for the neat epoxy and GNP/epoxy composites was similar. The GNP aspect ratio in the composite samples was confirmed to be similar to that of the as-received material by using the percolation threshold measured from electrical resistivity measurements. Using this GNP aspect ratio, the two-dimensional randomly oriented filler Halpin–Tsai model adjusted for platelet filler shape predicts the tensile modulus well for the GNP/epoxy composites. Per the authors' knowledge, mechanical properties and modeling for this GNP/epoxy system have never been reported in the open literature. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
TL;DR: In this paper, the critical carbon layer thickness for stable pull-out in a three layer unidirectional hybrid laminate was determined and a new approach and material architecture was presented in order to overcome the inherent brittleness and unstable failure characteristic of conventional high performance composites.
Abstract: A new approach and material architecture is presented in order to overcome the inherent brittleness and unstable failure characteristic of conventional high performance composites. The concept is the use of thin-ply hybrid laminates. Fracture mechanics calculations were carried out to determine the critical carbon layer thickness for stable pull-out in a three layer unidirectional hybrid laminate, which can provide a pseudo-ductile failure. Unidirectional hybrid composites were fabricated by sandwiching various numbers of thin carbon prepreg plies between standard thickness glass prepreg plies and tested in tension. Specimens with one and two plies of thin carbon prepreg produced pseudo-ductile failure, whereas ones with three and four plies failed with unstable delamination. An explanation of the different failure modes is given in terms of the different energy release rates for delamination in various specimens. The observed damage characteristics agreed well with the expectations according to the estimated critical carbon layer thickness.
TL;DR: In this paper, the authors review literature on the modification of epoxy resins and their properties, which are used for its industrial applications, and discuss the most useful valuable modifications for industrial applications.
Abstract: The article briefly reviews literature on the modification of epoxy resins and their properties, which are used for its industrial applications. Experimental results on modified epoxy resins are collectively summarized, which focus on the structure, curing, and alternate methods for modification of epoxy resins. The several properties such as thermal stability, adhesive, toughness, and electrical conductivity have been studied during the modifications of epoxy resins, which is useful in the field of electronic encapsulation, blending, composites, and nanocomposites, etc. The review concludes with a brief discussion on the most useful valuable modifications for industrial applications.
TL;DR: In this article, an aqueous suspension deposition method was used to coat the sized carbon fibers T700SC and T300B with commercially carboxylic acid-functionalized and hydroxyl functionalized carbon nanotubes (CNTs).
TL;DR: In this article, the effect of surface modification on mechanical properties was evaluated by tensile and impact tests under controlled conditions, and it was concluded that the enhancement of mechanical properties after coupling agent modification could be attributed to the formation of chemical bonds between the cellulose and the epoxy coupled with the coupling agent.
Abstract: Bamboo cellulose fibers were treated with NaOH aqueous solution and silane coupling agent, respectively, before they were applied into epoxy composites. The effect of surface modification on mechanical properties was evaluated by tensile and impact tests under controlled conditions. Compared with the untreated cellulose filled epoxy composites, the NaOH solution treatment increased the tensile strength by 34% and elongation at break by 31%. While silane coupling agent treatment produced 71% enhancement in tensile strength and 53% increase in elongation at break. The scanning electron microscopy (SEM) was used to observe the surface feature of the cellulose fibers and the tensile fractures as well as cryo-fractures of the composites. The Fourier transform infrared (FTIR) was employed to analyze the chemical structure of the cellulose fibers before and after modifications. The results indicated different mechanisms for the two modifications of cellulose. The NaOH solution partly dissolved the lignin and amorphous cellulose, which resulting in splitting the fibers into smaller size. This led to easier permeating into the gaps of the fibers for epoxy resin (EP) oligmer and forming effective interfacial adhesion. Based on the emergence of Si–O–C and Si–O–Si on the cellulose surface, it was concluded that the enhancement of mechanical properties after coupling agent modification could be ascribed to the formation of chemical bonds between the cellulose and the epoxy coupled with the coupling agent.
TL;DR: In this paper, a wash-and-rebuild process was used to synthesize amino-and epoxy-functionalized graphene oxide (APTS-GO) for nanocomposites, which yielded a 32% increase in Young's modulus (3.3 GPa) and 16 percent increase in tensile strength (81.2 MPa).
TL;DR: Graphene oxide (GO)/waterborne epoxy (EP) composites are prepared using an easy, all aqueous, in situ polymerization method as mentioned in this paper, leading to the formation of composites with a self-aligned layered structure and highly anisotropic properties between the direction of alignment and that perpendicular to it.
TL;DR: In this paper, the authors evaluated the tensile and flexural properties of hybrid glass fiber-sisal/jute reinforced epoxy composites and found that the incorporation of sisal fiber with GFRP exhibited superior properties.
TL;DR: In this article, a novel itaconic acid (IA) based epoxy resin with curable double bonds (EIA) was synthesized by the esterification reaction between IA and epichlorohydrin (ECH).
TL;DR: In this article, the filler percolation network of multi-walled carbon nanotubes (MWCNTs) grown by chemical vapor deposition and thermally reduced functionalized graphene sheets (FGSs) in an epoxy resin was evaluated by the plate-plate rheological response of un-cured dispersions and the electrical properties of cured materials.
TL;DR: In this paper, the abaca-jute hybrid composite has better properties than the traditional abaca composite alone in tensile and shear properties, however, the composite is superior to the hybrid composite in flexural and impact strength, and the internal structure of the composite was observed under scanning electron microscope (SEM) and the fractures, voids and fibre delamination were analyzed.
TL;DR: In this paper, the effect of adding multi-walled carbon nanotubes (MWCNTs) to the epoxy matrix of a carbon fiber reinforced composite (CFRP) was investigated.
TL;DR: In this article, a simple strategy for the preparation of composites with high dielectric constant and thermal conductivity was developed through a typical interface design, where Graphite nanoplatelets (GNPs) with a thickness of 20-50nm were fabricated and homogeneously dispersed in the epoxy matrix.
01 Jan 2013
TL;DR: In this paper, various surface preparations for copper and copper alloys including ferric chloride-nitric acid process, ferric sulfate-sulfuric acid/sodium dichromate-Sulfurica acid process and black oxide process are discussed.
Abstract: The chapter discusses various methods used to treat copper and copper alloys for adhesive bonding. The tendency of copper to form brittle amine compounds with the amine curing agents is one of the difficulties in its adhesive bonding. There are numerous reported surface preparations for copper and copper alloys including ferric chloride-nitric acid process, ferric sulfate-sulfuric acid/sodium dichromate-sulfuric acid process and black oxide process. A barrier layer on the surface of the metal can be formed by using the black oxide process. It provides a description on the evaluation of ferric chloride-nitric acid process and the ferric sulfate-sulfuric acid/sodium dichromate-sulfuric acid process with three epoxy type adhesive systems. The epoxy type adhesive system includes a two part polyamide-epoxy consisting of epoxy paste and curing epoxy film adhesive. It is also observed that with the use of ferric chloride-nitric acid process the resulting surfaces appear to be light-sensitive.
TL;DR: In this article, three different sized chemical functionalized graphene (GO) sheets were used to fabricate a series of epoxy/GO nanocomposites, and the results indicate that the incorporation of GO sheets were dramatically effective for improving the fracture toughness of the epoxy at a very significant low loading.
TL;DR: In this paper, a novel biobased epoxy thermoset was synthesized from gallic acid, a phenolic acid encountered in various plants, both in its simple form and as a part of gallotannins.
TL;DR: In this paper, the tribological performance of graphene oxide (GO)/epoxy nanocomposites is investigated for the first time at a very low GO weight fraction of 0.05-0.5%.
TL;DR: The preparation of epoxy nanocomposites, which had enhanced thermal conductivities but were still electrical insulators, incorporating hybrid nanosheets (NSs) with sandwich structures composed of thermally reduced graphene oxide (TRGO) and silica, were reported on.
Abstract: We herein report on the preparation of epoxy nanocomposites, which had enhanced thermal conductivities but were still electrical insulators, incorporating hybrid nanosheets (NSs) with sandwich structures composed of thermally reduced graphene oxide (TRGO) and silica. The silica layer covered the surface of the TRGO, hindering electrical conduction and effectively forming a 3D phonon transport channel that had a unique effect on the electrical and thermal properties of the epoxy matrix. A 1 wt% TRGO–silica NS epoxy nanocomposite maintained an electrical resistivity of 2.96 × 1011 Ω cm, and its thermal conductivity was 0.322 W m−1 K−1, which is 61% higher than the conductivity of an epoxy nanocomposite without TRGO–silica NSs (0.2 W m−1 K−1).
TL;DR: In this article, a constitutive damage model for an epoxy matrix on micromechanical analyses of polymer composite materials is presented. But the authors focus on the influence of the interface between fiber and matrix, as well as to the influence on the strength properties of the composite, damage initiation and propagation under different loading conditions.