Improvement Effect of Functionalized Cnts on Mechanical and Thermal Properties of Epoxy Matrix

2012 ◽  
Vol 217-219 ◽  
pp. 272-275 ◽  
Author(s):  
Wen Jing Zhang ◽  
Xiao Yan Li ◽  
Xia Wang ◽  
Deng Guang Yu ◽  
Wen Hui Qian ◽  
...  

Targeting at the brittleness of cured epoxy (EP), functionalized CNTs were integrated into the thermoset to make high-performance CNTs/EP nano-composites.In this investigation, polymaleic acid modified CNTs with a high surface grafting ratio (PMA-CNTs)was prepared through the plasma induced grafting technique , then further functionalized with amino groups to yield A-PMA-CNTs, which were then incorporated into epoxy matrix. Characterization of mechanical properties and heat resistance of the A-PMA-CNTs/EP nanocomposites indicates that A-PMA-CNTs can significantly strengthen and toughen the epoxy resin, with an increased glass transition temperature.

2012 ◽  
Vol 730-732 ◽  
pp. 277-282 ◽  
Author(s):  
Janaina L. Leite ◽  
Gean V. Salmoria ◽  
Carlos H. Ahrens ◽  
António Sergio Pouzada

Metallic fibres in polymeric matrix are used for mouldings blocks of hybrid injection moulds improving the mechanical and thermal properties. This paper reports on the characterization of epoxy resin/short steel fibres (SSF) composites. The effect of the concentration of 2,4,6-tris (dimethylamino-methyl) phenol as accelerator in the epoxy system was evaluated by viscosity and dynamical mechanical analyses. The composites were characterized by compression and microhardness tests. The fibres dispersion into the epoxy matrix was analysed by optical microscopy. It was found that the best accelerator concentration for this type of composite was 5,0 parts by weight


1991 ◽  
Vol 12 (4) ◽  
pp. 273-280 ◽  
Author(s):  
E. M. Woo ◽  
J. C. Seferis ◽  
R. S. Schaffnit

e-Polymers ◽  
2013 ◽  
Vol 13 (1) ◽  
Author(s):  
Fangting Chi ◽  
Jie Xiong ◽  
Sheng Hu ◽  
Jingwei Hou ◽  
Mei Gu ◽  
...  

Abstract Amidoxime-based adsorbents are widely investigated as the main adsorbent in the recovery of uranium from seawater. However, the adsorption rate and loading capacity of such adsorbents should be further improved due to the economic viability consideration. In this paper, the adsorption properties of amidoxime-based adsorbent were enhanced through the cografting of amino groups. The acrylonitrile (AN) and glycidyl methacrylate (GMA) were firstly cografted onto polypropylene fibers by preirradiation grafting technique. Then the cografted fibers were treated with ethylenediamine to convert GMA to amino group, following treated with hydroxylamine to convert AN groups to amidoxime (AO) group. Fourier transform infrared spectroscopy, scanning electron microscopy and contact angle measurement were used to characterize the structure of the adsorbent. The results showed that the amidoxime and amino groups had been successfully grafted onto the polypropylene fibers. For AO fiber, high adsorption rate was observed within the first 30 min and the plateau value of 42.3% uranium loading (0.0904mg/g) was reached at around 30 min. The AO/amine fibers exhibited a higher adsorption rate. The adsorption equilibrium for AO/amine fiber was attained within 20 min, resulting in the adsorption of 93.3% uranium loading (0.191mg/g). Additionally, AO/amine fibers can avoid pH reducing for better adsorption efficiency.


2015 ◽  
Vol 754-755 ◽  
pp. 135-139 ◽  
Author(s):  
Muhammad Razlan Zakaria ◽  
Hazizan Md. Akil ◽  
Muhammad Helmi Abdul Kudus ◽  
Mohd Zharif Ahmad Thirmizir

This paper presents the multi-scale hybridization of carbon nanotube (CNT) with microparticles in polymers which offers new opportunity to develop high performance multifunctional composites. The hybrid carbon nanotube-alumina (CNT-Al2O3) compound was synthesized via chemical vapour deposition (CVD) by direct growth of CNT on alumina particles. This hybrid CNT-Al2O3 compound was incorporated into the epoxy matrix at various filler loadings (i.e., 1–5%) and compared to physically mixed CNT-Al2O3. The CNT-Al2O3 hybrid epoxy composites showed higher hardness compared to the CNT-Al2O3 physically mixed epoxy composites. This enhancement was associated with the homogenous dispersion of CNT-Al2O3 hybrid compound in the epoxy matrix.


1984 ◽  
Vol 51 (01) ◽  
pp. 016-021 ◽  
Author(s):  
S Birken ◽  
G Agosto ◽  
B Lahiri ◽  
R Canfield

SummaryIn order to investigate the early release of NH2-terminal plasmic fragments from the Bβ chain of fibrinogen, substantial quantities of Bβ 1-42 and Bβ 1-21 are required as immunogens, as radioimmunoassay standards and for infusion into human volunteers to determine the half-lives of these peptides. Towards this end methods that employ selective proteolytic cleavage of these fragments from fibrinogen have been developed. Both the N-DSK fragment, produced by CNBr cleavage of fibrinogen, and Bβ 1-118 were employed as substrates for plasmin with the finding of higher yields from N-DSK. Bβ 1-42 and Bβ 1-21 were purified by gel filtration and ion-exchange chromatography on SP-Sephadex using volatile buffers. When the purified preparation of Bβ 1-42 was chromatographed on reverse-phase high performance liquid chromatography, two peaks of identical amino acid composition were separated, presumably due either to pyroglutamate or to amide differences.


1992 ◽  
Vol 57 (10) ◽  
pp. 2151-2156 ◽  
Author(s):  
Peter Chabreček ◽  
Ladislav Šoltés ◽  
Hynek Hradec ◽  
Jiří Filip ◽  
Eduard Orviský

Two methods for the preparation of high molecular weight [3H]hyaluronic acid were investigated. In the first one, hydrogen atoms in the molecule were replaced by tritium. This isotopic substitution was performed in aqueous solution using Pd/CaCO3 as the catalyst. In the second method, the high molecular weight hyaluronic acid was alkylated with [3H]methyl bromide in liquid ammonia at a temperature of -33.5 °C. High-performance gel permeation chromatographic separation method was used for the isolation and characterization of the high molecular weight [3H]hyaluronic acid. Molecular weight parameters for the labelled biopolymers were Mw = 128 kDa, Mw/Mn = 1.88 (first method) and Mw = 268 kDa, Mw/Mn = 1.55 (second method). The high molecular weight [3H]hyaluronic acid having Mw = 268 kDa was degraded further by specific hyaluronidase. Products of the enzymatic depolymerization were observed to be identical for both, labelled and cold biopolymer. This finding indicates that the described labelling procedure using [3H]methyl bromide does not induce any major structural rearrangements in the molecule.


2019 ◽  
pp. 089270571987822
Author(s):  
Saud Aldajah ◽  
Mohammad Y Al-Haik ◽  
Waseem Siddique ◽  
Mohammad M Kabir ◽  
Yousef Haik

This study reveals the enhancement of mechanical and thermal properties of maleic anhydride-grafted polypropylene (PP- g-MA) with the addition of nanocrystalline cellulose (NCC). A nanocomposite was manufactured by blending various percentages of PP, MA, and NCC nanoparticles by means of a twin-screw extruder. The influence of varying the percentages of NCC on the mechanical and thermal behavior of the nanocomposite was studied by performing three-point bending, nanoindentation, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy tests. The novelty of this study stems on the NCC nanoparticles and their ability to enhance the mechanical and thermal properties of PP. Three-point bending and nanoindentation tests revealed improvement in the mechanical properties in terms of strength, modulus, and hardness of the PP- g-MA nanocomposites as the addition of NCC increased. SEM showed homogeneity between the mixtures which proved the presence of interfacial adhesion between the PP- g-MA incorporated with NCC nanoparticles that was confirmed by the FTIR results. DSC and TGA measurements showed that the thermal stability of the nanocomposites was not compromised due to the addition of the coupling agent and reinforced nanoparticles.


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