In this study, the thermal, dynamic-mechanical and tribological behavior of nanocomposites of a photocurable epoxy-acrylate resin and multiwalled carbon nanotubes (MWCNT) are investigated. A route consisting of a combination of sonication, mechanical and magnetic stirring is used to disperse 0.25-0.75 wt. (%) MWCNT into the resin. Two photocuring cycles using 12 hours and 24 hours of UV-A radiation are studied. The storage modulus, the loss modulus and the tan delta are obtained by dynamic mechanical analysis. Thermal stability is investigated by thermogravimetry, morphology by transmission electronic microscopy (TEM) and tribological performance using a pin-on-disk apparatus. The results indicate an increase in stiffness and higher ability to dissipate energy, as well as a shift in the glass transition temperature for the nanocomposites. The addition of nanofillers also decreased friction coefficient and wear rate of the nanocomposites but did not change the observed wear mechanisms.
Phase transitions and structural and magnetic properties of rapidly solidified Ni50Mn38Sn12 alloy ribbons have been studied. Ribbon samples crystallize as a single-phase, ten-layered modulated (10M) monoclinic martensite with a columnar-grain microstructure and a magnetic transition temperature of 308 K. By decreasing the temperature, martensite undergoes an intermartensitic phase transition around 195 K. Above room temperature, the high temperature martensite transforms into austenite. Below 10...
Last. Marco Sangermano(Polytechnic University of Turin)H-Index: 52
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Abstract In this work, the effect of several carbon fillers, exfoliated graphite (EG), functionalized graphene sheets (FGS), multi-walled carbon nanotubes (MWCNTs), and oxidized multi-walled carbon nanotubes (f-MWCNTs), were compared on the curing process and physical properties of a cationically photocurable epoxy resin. The extent of the photopolymerization was monitored by Real-Time FTIR spectroscopy. It was found that all the nanofillers delayed the curing reaction probably due to a shieldin...
#2Carlos V. Opelt(UDESC: Universidade do Estado de Santa Catarina)H-Index: 8
Last. Luiz A. F. Coelho(UDESC: Universidade do Estado de Santa Catarina)H-Index: 17
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Abstract In this work, thermal and mechanical behaviors of nanocomposites of a photocurable epoxyacrylate resin and multiwalled carbon nanotubes (MWCNT) were investigated. A combination of sonication, and mechanical and magnetic stirring was used to disperse 0.25 wt% and 0.75 wt% of MWCNTs into the resin. Two photocuring cycles using 12 and 24 h UV-A radiation were studied. Nanoindentation was the chosen technique for characterizing the modulus of elasticity and hardness of samples. The curing d...
Abstract Multiwall carbon nanotubes were coated with copper using an electroless two-step sensitization–activation method in order to improve the interfacial strength of the metal matrix. Copper-coated carbon nanotubes (5–20 vol.%) were mixed with copper metal powder and microwave heating was used to sinter them. The composites were subjected to pin-on-disc testing to study their tribological characteristics. Their mechanical and tribological properties were comparable to those of conventional a...
Abstract This paper examines the recent advancements in the science and technology of carbon nanotube (CNT)-based fibers and composites. The assessment is made according to the hierarchical structural levels of CNTs used in composites, ranging from 1-D to 2-D to 3-D. At the 1-D level, fibers composed of pure CNTs or CNTs embedded in a polymeric matrix produced by various techniques are reviewed. At the 2-D level, the focuses are on CNT-modified advanced fibers, CNT-modified interlaminar surfaces...
Polypropylene (PP) nanocomposites with multi-walled carbon nanotubes (CNT) were produced by a small-scale masterbatch melt dilution technique using five PP differing in melt flow index (MFI) and degree of maleination. PP used in a masterbatch has MFI = 12 (PP12), the others used PP which have MFI = 2 or MFI = 8. The state of CNT dispersion as assessed by melt rheological and morphological investigations indicated a better dispersion when using unmodified PP with MFI = 8 (PP8) and the masterbatch...
We demonstrate the alignment of multiwalled carbon nanotubes in bulk epoxy matrices by application of external electric field. The composites were prepared by a macro-layer-by-layer method; UV light was used to rapidly polymerize the epoxy and preserve the aligned nanotube network. The nanotube alignment generated strong anisotropy in the composite’s properties. The composite’s storage modulus was increased by ∼50%, and the electrical conductivity was improved by four orders of magnitude in the ...
Systematic dc and ac magnetic susceptibility measurements performed on RuSr2Eu1.5Ce0.5Cu2O10−δ (Ru1222) demonstrate a paramagnetic to ferromagnetic transition around 95 K. The third harmonic of the ac susceptibility reveals that the system undergoes a spin glass transition below 75 K. The features of the zero-field cooled and field cooled dc magnetization curves of Ru1222 material resemble those of a cluster glass state, rather than those of a canonical spin glass state. The magnetization versus...
#2Zhong-Zhen Yu(Huada: Beijing University of Chemical Technology)H-Index: 86
Last. Yiu-Wing Mai(USYD: University of Sydney)H-Index: 112
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It is realized that the addition of a small percentage of rigid nanoparticles to polymers significantly improves many of their mechanical properties, especially stiffness and strength. Such improvements are often attributed to the availability of large numbers of nanoparticles with huge interfacial areas compared to their macro- and micro-scale counterparts. In particular, from the tribological viewpoint, the small size of nanoparticles with homogenous dispersion in the matrix and good interfaci...
Last. Luiz A. F. Coelho(UDESC: Universidade do Estado de Santa Catarina)H-Index: 17
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In this study, randomly oriented single-walled carbon nanotubes (SWCNTs)/epoxy nanocomposites were fabricated by tip sonication with the aid of a solvent and subsequent casting. Two different curing cycles were used to study the role of the stiffness of the epoxy matrix on the tensile and thermal behavior of the composites. The addition of a small amount of SWCNTs (0.25 wt.%) in rubbery, i.e., soft matrices, greatly increased Young’s modulus and tensile strength of the nanocomposites. The result...
Abstract null null New meta- and para-cyanoderivatives of 1,4-di(styryl)benzene and 1,3-di(styryl)benzene were synthesized and investigated for their use as photosensitizers of iodonium salt for various photopolymerization processes. Detail spectroscopic characteristic of this compound were performed, and the mechanism of initiation in binary photoinitiating system together with iodine salt was discussed and confirmed by experiments. Using real-time FTIR, the usefulness of the proposed meta- and...
Abstract The tribological performance of new epoxy resin (RE) coatings on mild steel AISI 1015 substrate has been studied under pin-on-disk configuration against AISI 316L stainless steel. Both single layer and double layer coatings were obtained by spin coating and curing. A single layer coating of RE modified by a dispersion of graphene (G) in the aprotic ionic liquid 1-octyl-3-methylimidazolium tetrafluoroborate, RE+9 wt.%([OMIM]BF4+0.1 wt.%G), prevents wear and reduces the coefficient of fri...
A series of 2-(diethylamino)-4-(1-ethylpropyl)-6-phenyl-benzene-1,3-dicarbonitrile derivatives were investigated in terms of photosensitisation in various photopolymerization processes in UV-A and vis light conditions. A full spectroscopic analysis of the tested compounds was performed. In addition to excellent spectroscopic properties, these compounds enable highly efficient photopolymerization processes, including free-radical, cationic and hybrid photopolymerization. As proven by a real-time ...
Acrylate/carbon nanotubes nanocomposites were prepared using sol-gel method. Carbon nanotubes with different percentage (0.2%, 0.4%, 0.6%, 0.8% and 1.0%) incorporated into acrylate and deposited on mild steel. Surface of acrylate/carbon nanotubes composites were characterized using by field emission scanning electron microscope (FESEM). Carbon nanotubes uniformly distributed in acrylate observed by FESEM shows increase in percentage of carbon nanotubes blend with acrylate the peak distribution b...
#1Karl S. Wagner(UMN: University of Minnesota)H-Index: 1
This paper aims to inform the reader about the aspects of compositing carbon nanotubes in photo curable resin that is commonly used in stereo lithography 3D printers. The focus is to increase the strength of the resin to allow for a greater range of objects to be printed with SLA printers. The paper will look at the different types of carbon nanotubes that can be used, what weight percent of nanotubes in resin will most likely work best in a printing environment based on surface hardness and cur...
The wear of parts because of friction is becoming the major problem for replacement of any product. The present research work is aimed to minimize the specific wear rate by fabricating the composite material by using multi walled carbon nanotube (MWCNT) as reinforcement. In this study the MWCNT is functionalized and then it is mixed with epoxy matrix composite by employing the chemical functionalization. Various characterization tests are done in order to predict various properties, nature and s...