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1.
The influence of the content of carbon nanofillers (multi-and single-wall nanotubes) on the thermophysical properties of epoxy
nanocomposites was investigated on the temperature range from −150 to 150°C. A “plateau” was found to exist in the concentration
dependence of thermal conductivity on the concentration interval from 0.1 to 1.0 wt.% carbon nanotubes (CNTs). The thermal
conductivity of the CNT composites exceeded that of pure epoxy resin by about 40%. A further increase in CNT content de creased
the conductivity, owing to increasing interfaces between the two phases and the additional thermal resistance caused by phonon
scattering on them. It is found that the temperature interval of transition of the composite from a glassy to a viscoelastic
state greatly depends on the filler type and concentration. There exists a critical concentration at which a drop in the glass-transition
temperature by 30% can be observed. The reason is the undercure of binder as a result of interaction between CNTs and epoxy
macromolecules, which reduces the cross-linking density of structure of the polymer.
Translated from Mekhanika Kompozitnykh Materialov, Vol. 44, No. 5, pp. 697–708, September–October, 2008. 相似文献
2.
M. H. G. Wichmann J. Sumfleth B. Fiedler F. H. Gojny K. Schulte 《Mechanics of Composite Materials》2006,42(5):395-406
A masterbatch process based on a minicalander (three-roller mill) and a vacuum dissolver was developed in order to produce
multiwall carbon nanotube/epoxy composites with loading fractions of 0.5, 1.0, and 2.0 wt.%. TEM and SEM analyses were performed
to investigate the dispersion results. A contrast imaging in the SEM backscattering mode revealed a homogeneous distribution
of carbon nanotubes in the whole volume of the material. Furthermore, an interesting correlation was found to exist between
the network structure formed by the nanotubes in the epoxy matrix and the appearance of fracture surface of the nanocomposites.
Furthermore, the nanocomposites exhibited an electrical conductivity in the regime of some 10−2 S/m.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 42, No. 5, pp. 567–582, September–October, 2006. 相似文献
3.
By introducing a new simplified 3D representative volume element for wavy carbon nanotubes, an analytical model is developed
to study the stress transfer in single-walled carbon nanotube-reinforced polymer composites. Based on the pull-out modeling
technique, the effects of waviness, aspect ratio, and Poisson ratio on the axial and interfacial shear stresses are analyzed
in detail. The results of the present analytical model are in a good agreement with corresponding results for straight nanotubes.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 45, No. 2, pp. 299-306, March-April, 2009. 相似文献
4.
The dependence of physical and mechanical properties of monolithic and foamed rigid polyurethanes on the content of flame
retardants was investigated at 293 and 98 K. The character of the influence of the content of trichloroethyl phosphate on
the ultimate tensile elongation and the coefficient of linear thermal expansion for monolithic and foamed polyurethanes at
a temperature of 98 K was established.
Latvian State Institute of Wood Chemistry, Riga, LV-1006 Latvia. Translated from Mekhanika Kompozitnykh Materialov, Vol. 35,
No. 5, pp. 671–676, September–October, 1999. 相似文献
5.
The dependence of physical and mechanical properties of oligoether-based foam polyurethanes on the molecular mass (Mc) of polymer chains between the nodes of the polymer network and on the content of rigid segments in the polymer is investigated at 293 and 98K. The values of Mc at which the foam plastics have the best mechanical properties at low temperatures are determined. The content of rigid segments in the polymer at which foam polyurethanes have the best combination of the linear thermal expansion coefficient and mechanical properties in tension at a temperature of 98K is found.Latvian State Institute of Wood Chemistry, Riga, LV-1006, Latvia. Translated from Mekhanika Kompozitnykh Materialov, Vol. 35, No. 4, pp. 517–526, July–August, 1999. 相似文献
6.
Properties of GaAs single crystals grown at low temperatures by molecular beam epitaxy (LTMBE GaAs) have been studied. The
results show that excessive arsenic atoms of about 1020 cm−3 exist in LTMBE GaAs in the form of arsenic interstitial couples, and cause the dilation in lattice parameter of LTMBE GaAs.
The arsenic interstitial couples will be decomposed, and the excessive arsenic atoms will precipitate during the annealing
above 300°C. Arsenic precipitates accumulate in the junctions of epilayers with the increase in the temperature of annealing.
The depletion regions caused by arsenic precipitates overlap each other in LTMBE GaAs, taking on the character of high resistivity,
and the effects of backgating or sidegating are effectively restrained. 相似文献
7.
Isaac Lare Animasaun 《Journal of the Egyptian Mathematical Society》2017,25(1):79-85
Steady mixed convection micropolar fluid flow towards stagnation point formed on horizontal linearly stretchable melting surface is studied. The vortex viscosity of micropolar fluid along a melting surface is proposed as a constant function of temperature while dynamic viscosity and thermal conductivity are temperature dependent due to the influence of internal heat source on the fluid. Similarity transformations were used to convert the governing equation into non-linear ODE and solved numerically. A parametric study is conducted. An analysis of the results obtained shows that the flow-field is influenced appreciably by heat source, melting, velocity ratio, variable viscosity and thermal conductivity. 相似文献