Mohamed KHARRAT
,
Maher DAMMAK
,
Amine CHARFI
材料科学技术（英文）
Fibre-matrix interface is known to have contribution to the mechanical performance of fibre-reinforced composite by its potential for load transfer between the fibre and the matrix. Such load transfer is of great importance in dentistry when a post is used for fixing a ceramic crown on the tooth. In this study, a pull-out test was carried out to analyse the interfacial properties of a steel fibre embedded in a polyester and epoxy matrices. It was found that the fibre-matrix interface is debonded on the whole embedded length when the fibre stress reached the debonding stress. Then, the fibre stress fell down to the initial extraction stress required to pulling out the debonded fibre from the matrix. Both debonding stress and initial extraction stress initiated a linear increase with the implantation length after the debonding stress reached horizontal asymptotes. To analyse the fibre-matrix load transfer before debonding, an analytical shear-lag model was adopted to in this test conditions. Fitting the experimental results with the analytical model provided the interfacial shear strength. By considering the Coulomb friction at the fibre-matrix interface during the fibre extraction process, an analytical model which considers Poisson's effects on both fibre and matrix, was developed. In this model, knowledge of the initial extraction stress of the fibre provides the residual normal stress at the fibre-matrix interface.
关键词:
Fibre
,
null
,
null
,
null
,
null
,
null
,
null
WU Zhichun YU Shuqiu CHEN Jiayong CHEN Chiayung Institute of Chemical Metallurgy
,
Academia Sinica
,
Beijing
,
China
金属学报(英文版)
The tertiary amine can be used to extract Fe(Ⅲ) very effectively in the pH range resulting in partial hydrolysis of Fe~(3+) ions.The iron extracted into the organic phase can be stripped rather easily with dilute H_2SO_4 or even with H_2O.Fe(Ⅲ) is extracted into the tertiary amine sulfate solution in the form of[(R_3NH)_2Fe(OH)(SO_4)_2]_2 complex by adduct formation.Equa- tion was derived to represent the chemical reactions involved during extraction.From the infrared spectrum studies on the extraction species in waxy solid form separated from the so- lution,sulfate group is a bidentate ligand to the iron atom.The extraction species has been considered to contain (FeOH)_2 unit based on the ultra violet spectra.The possible structure of the extraction species has been proposed.
关键词:
tertiary amine
,
null
,
null
,
null
LIU Huizhou
,
YU Shuqiu
,
CHEN Jiayong
,
Institute of Chemical Metallurgy
,
Academia Sinica
,
Beijing
,
China LIU Huizhou
,
Institute of Chemical Metallurgy
,
Academia Sinica
,
Beijing 100080
,
China
金属学报(英文版)
Mechanism of extraction of Fe (III) from sulphate solution by primary amine N1923 and stripping of Fe loaded organic phase with dilute H_2SO_4 was investigated. The organic phase was characterized by FT-IR and photon correlation spectroscopy. The composition of extracted species as well as the content of H_2O in organic phase were determined. The dependence of both the rate of extraction and stripping on the formation of reverse micelle in primary amine (N1923)system has been confirmed. It is shown that the extraction of Fe(III) by primary amine sulphate may be related to the adduct formation or cation exchange reaction under different concentrations of H_2SO_4 in aqueous solution.
关键词:
Fe(III)
,
null
,
null
,
null
Bulletin of Electrochemistry
The performance of inhibition mechanism and desorption behaviour of the N,N-dipropynoxy methyl amine trimethyl phosphonate for iron in hydrochloric acid were investigated by means of static polarization technique and the electrochemical impedance spectrum, The results show that N,N-dipropynoxy methyl amine trimethyl phosphonate possesses high inhibition efficiency and shows geometric blocking effect, It is also found that this inhibitor obeys the Freundulich adsorption isotherm. With the increase of anodic potential, a low frequency inductive are was observed.
关键词:
inhibition;desorption;adsorption and EIS
MA Genxiang LI Deqian Changchun Institute of Applied Chemistry
,
Academia Sinica
,
Changchun
,
China Changchun Institute of Applied Chemistry
,
Academia Sinica
,
Changchun
,
Jilin
,
China
金属学报(英文版)
The synergistic extraction of Cd(Ⅱ)with primary amine N-1923 and neutral organophosphorus reagents(TBP,DBBP,B)from hydrochloric acid has been investigated at μ=0.5,t=25℃.The compositions of the synergistic extraction complexes and the mechanism of the synergistic extraction have been determined by the methods of slope and constant mole. The synergistic extraction complexes with composition(RNH_3Cl)_2·CdCl_2·B have been demonstrated.The synergistic extraction reactions and additional reaction of Cd(Ⅱ)have been proposed as follows: CdCl_2+2RNH_3Cl_(o)+B_(o)(RNH_3Cl)_2·CdCl_2·B_(o) (RNH_3Cl)_3·CdCl_(2(o)+B_(o)(RNH_3Cl)_2·CdCl_2·B_(o)+RNH_3Cl_(o) In addition,the equilibrium constants and the thermodynamic functions of the synergistic ex- traction reactions have been calculated.The IR and NMR spectra of the synergistic ext-ac- tion complexes of Cd(Ⅱ)have been studied as well.
关键词:
primary amine
,
null
,
null
,
null
B.C.Samanta
,
T.Maity
材料科学技术（英文）
An investigation was carried out to modify the toughness of triethylene tetramine cured DGEBA (diglycidyl ether of bisphenol-A) resin using solid amine terminated poly (ethylene glycol) benzoate (ATPEGB) as modifier with and without red mud waste particles. The solid ATPEGB modifier synthesized from the acid catalyzed esterification reaction of poly (ethylene glycol) (PEG) and 4-amino benzoic acid was characterized by Fourier transform infrared spectroscopy (FT-IR) and 1H-NMR (nuclear magnetic resonance) spectroscopies, viscosity measurements, and solubility parameter calculation. The unfilled and red mud waste filled modified epoxy networks were evaluated with impact, adhesive, tensile, flexural and thermal properties by differential scanning calorimetry (DSC), thermogravimetric (TG) and dynamic mechanical analysis (DMA). The effect of modifier concentration and red mud waste particles on toughening behavior was also investigated. The optimum properties were obtained at 12.5 phr (parts per hundred parts of resin) concentration of the modifier. The ATPEGB modified cured epoxy was thermally stable up to 315℃. The morphology on fracture surfaces of cured epoxy was also analyzed by scanning electron microscopy (SEM).
关键词:
Epoxy
,
toughness
,
adhesive
,
morphology
