Effect of block-copolymer dispersants on properties of carbon nanotube/epoxy systems (original) (raw)
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Carbon nanotube/epoxy resin composites using a block copolymer as a dispersing agent
physica status solidi (a), 2004
Strengthening of carbon nanotube/epoxy resin composites was achieved by adding a small amount of copolymer (0.03 wt% of epoxy resin) as a dispersant. Tensile testing was used to measure mechanical properties. Young's modulus and fracture stress of the carbon nanotube composites with the copolymer were found to be about 50% higher than for the pure epoxy resin, and about 20% higher than for the composite without the dispersing agent. 131 6508704, Fax: +44 3470 phys. stat. sol. (a) 201, No. 13 (2004) / www.pss-a.com R91
2008
The epoxy matrix of a carbon fiber/epoxy composite was modified with multiwall carbon nanotubes (MWCNTs) to improve the matrix dominated thermomechanical properties of the composite. Effects of improved dispersion and nanotube length on reinforcement of the composite were investigated experimentally. The dispersion of the CNTs was enhanced with a block copolymer. Two different CNT lengths, 1 and 10 lm on average, were considered. Irrespective of the length, a pronounced improvement of the composite properties was achieved with 0.5 wt% of MWCNTs with the use of block copolymer. Without the block copolymer, it was found that a higher enhancement of composite properties was achieved with the longer nanotubes.
Carbon nanotube (CNT)–epoxy nanocomposites: a systematic investigation of CNT dispersion
Journal of Nanoparticle Research, 2011
A systematic investigation of the dispersion of carbon nanotubes (CNTs), 1-6 nm in diameter and a few microns in length, in a bisphenol F-based epoxy resin has been presented. Several dispersing techniques including high-speed dissolver, ultrasonic bath/horn, 3-roll mill, etc. have been employed. Optical microscopy has been extensively used to systematically characterise the state of CNT dispersion in the epoxy resin during the entire processing cycle from mixing CNT with resin to adding and curing with hardener. Complimentary viscosity measurements were also performed at various stages of nanocomposite processing. A method to produce a good CNT dispersion in resin was established, but the state of CNT dispersion was found to be extremely sensitive to its physical and chemical environments. The cured nanocomposites were further tested for their thermo-mechanical properties by dynamic mechanical thermal analysis (DMTA), and for flexural and compressive mechanical properties. The measured properties of various nanocomposite plates were then discussed in view of the corresponding CNT dispersion. Keywords Carbon nanotubes Á Epoxy resin Á Nanocomposites Á Stability of dispersion Á Dispersing agent Á Optical microscopy Á Mechanical properties Á Flexural and compressive strengths
The effect of the surface modification of carbon nanotubes on their dispersion in the epoxy matrix
Polish Journal of Chemical Technology, 2011
Functionalization of multi-walled carbon nanotubes (MWCNTs) has an effect on the dispersion of MWCNT in the epoxy matrix. Samples based on two kinds of epoxy resin and different weight percentage of MWCNTs (functionalized and non-functionalized) were prepared. Epoxy/carbon nanotubes composites were prepared by different mixing methods (ultrasounds and a combination of ultrasounds and mechanical mixing). CNTs modified with different functional groups were investigated. Surfactants were used to lower the surface tension of the liquid, which enabled easier spreading and reducing the interfacial tension. Solvents were also used to reduce the liquid viscosity. Some of them facilitate homogeneous dispersion of nanotubes in the resin. The properties of epoxy/nanotubes composites strongly depend on a uniform distribution of carbon nanotubes in the epoxy matrix. The type of epoxy resin, solvent, surfactant and mixing method for homogeneous dispersion of CNTs in the epoxy matrix was evaluated. The effect of CNTs functionalization type on their dispersion in the epoxy resins was evaluated on the basis of viscosity and microstructure studies.
Effect of SWCNT dispersion on epoxy nanocomposite properties
Polymer Composites, 2012
In nanocomposites containing single wall carbon nanotubes (SWCNTs), the final properties strongly depend on the dispersion quality of these fillers. Various methods have been used to improve the dispersion of nanofillers; however, one of the most effective ways is to functionalize carbon nanotubes (CNTs) with covalent and noncovalent functional groups. In this work, the dispersion of SWCNTs in an epoxy system was studied by using surfactants, acid (COOH), and ester groups (PGE)-modified CNTs. Rheological and scanning electron microscopy analysis showed that functionalization of CNTs helped in improving the dispersion of fillers in the epoxy matrix. Systems with surfactant modified SWCNTs (1 wt%) exhibited the highest storage modulus at low frequencies after 5-min sonication. This behavior is associated to a stronger network of fillers as a result of a good dispersion. However, longer sonication times lowered the storage modulus, corresponding to a degradation of the tubes. The effect of the dispersion quality on mechanical properties was also studied using a three-point bending setup .
Journal of Polymer Research, 2000
A suitable dispersion technique and quantitative evaluation of degree of dispersion of carbon nanotubes (CNT) in any solvent and matrix system has been one of the key issues for achieving enhanced performance of CNT reinforced composites. We report the use of UV–vis spectroscopy as a useful technique to ascertain the degree of dispersion of multiwalled carbon nanotubes (MWCNT) in the epoxy resin. The study has enabled to maximize dispersion of MWCNT in the epoxy resin using two different routes. As a result the composite samples prepared with only 0.3 wt.% amine functionalized MWCNT showed flexural strength of 140 MPa over the neat resin value of 55 MPa, an improvement of ~155% which is maximum reported so far for CNT-epoxy isotropic composites.
Composites Part B: Engineering, 2012
In this work, multi wall carbon nanotubes (MWCNTs) dispersed in a polymer matrix have been used to enhance the thermo-mechanical and toughness properties of the resulting nanocomposites. Dynamic mechanical analysis (DMA), tensile tests and single edge notch 3-point bending tests were performed on unfilled, 0.5 and 1 wt.% carbon nanotube (CNT)-filled epoxy to identify the effect of loading on the aforementioned properties. The effect of the dispersion conditions has been thoroughly investigated with regard to the CNT content, the sonication time and the total sonication energy input. The CNT dispersion conditions were of key importance for both the thermo-mechanical and toughness properties of the modified systems. Sonication duration of 1 h was the most effective for the storage modulus and glass transition temperature (T g ) enhancement for both 0.5 and 1 wt.% CNT loadings. The significant increase of the storage modulus and T g under specific sonication conditions was associated with the improved dispersion and interfacial bonding between the CNTs and the epoxy matrix. Sonication energy was the influencing parameter for the toughness properties. Best results were obtained for 2 h of sonication and 50% sonication amplitude. It was suggested that this level of sonication allowed appropriate dispersion of the CNTs to the epoxy matrices without destroying the CNT's structure.
Polymer Engineering & Science, 2018
In this study, the dispersion of multi-walled carbon nanotubes (MWCNTs) in epoxy was facilitated by an anionic surfactant, linear alkyl benzene sulfonic acid. Different types of composites were prepared using a fixed amount of MWCNTs (0.5 wt%), in absence of solvent/surfactant, in presence of solvent and solvent/surfactant. The composites were characterized using Fourier transform infrared spectrophotometer, thermogravimetric analyzer (TGA), differential scanning calorimeter (DSC), universal testing machine, pendulum impact system, X-ray diffraction, and scanning electron microscope. The epoxy/MWCNTs nanocomposite exhibited significantly higher mechanical properties due to the better dispersion in the presence of the surfactant. The tensile strength and flexural strength were increased by 75% and 108%, respectively. The thermal, structural, and morphological analyses were also excellent as a result of the better dispersion. In addition, the solventsurfactant behavior was hypothesized for the epoxy/ MWCNTs system.
Dispersion of carbon nanotubes in nanostructured epoxy systems for coating application
Progress in Organic Coatings, 2014
This study about the dispersion of carbon nanotubes into an epoxy matrix can be considered as a first approach to investigate a potential industrial coating. In order to well disperse carboxylic acid-modified multiwalled carbon nanotubes (a-MWCNT) in a commercial epoxy-based resin, its nanostructuring with an amphiphilic epoxidized styrene-b-butadiene-b-styrene triblock copolymer that also acts as surfactant was carried out. In order to determine if coating performance is suitable for industrial applications, morphologies generated for copolymer-modified coating and the dispersion of a-MWCNT was characterized by atomic force microscopy. Contact angle measurements, Taber abrasion testing and thermogravimetric analysis were also performed. A tailor-made coating was developed with improved a-MWCNT dispersion and hydrophobicity due to the effect of block copolymer. System modified with 5 wt% of block copolymer and filled with 1 wt% a-MWCNT present the lowest value in weight loss in the wear test, while systems filled with 0.2 wt% of a-MWCNT showed increased thermal stability. Coating properties analyzed depend largely on the amount of components and a-MWCNT dispersion level, thus adding new application possibilities to the coatings, while most of the conventional epoxy-coating advantages are retained.
Effect of processing techniques on the performance of Epoxy/MWCNT nanocomposites
The aim of this study is to investigate the optimum technique to disperse Multi-Walled Carbon Nanotubes (MWCNTs) in SC-1 epoxy uniformly and to evaluate the effect of processing technique on the performance of SC-1 epoxy. To achieve better dispersion, MWCNT was mixed with SC-1 resin directly or premixed with a solvent and then mixed with SC-1 resin after evaporating the solvent using sonication, thinky mixing and three-roll mill methods either in isolation or combination. Flexural tests were performed to evaluate mechanical performances and results exhibit up to 27.13, 13.51, and 21.99% improvement on flexural strength, flexural modulus, and maximum strain, respectively, over neat epoxy with only 0.2 wt % loading. Dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) indicated improvement in storage modulus, T g , inflection temperature, and residue content, respectively over neat SC-1 epoxy. Thermal and mechanical properties at higher loading conditions were seen to either reduce or not significantly improve. This was attributed to high viscosity of nanocomposites as determined by rheological analysis which prevents good dispersion of MWNCTs into epoxy system at 0.4 wt % loading.