Composites with an elastomeric matrix containing rigid particles of diameter 10–1000 μm are studied. One of possible mechanisms
of the rheological behavior of such filled systems, related to the origination and growth of vacuoles near the rigid inclusions
in a viscous matrix, is considered. For simulating the mechanism of formation of rheological properties of the filled elastomers,
we use a structural cell in the form of an elastomeric cylinder, whose height and diameter are equal in magnitude, with a
rigid spherical inclusion at its center. Deformation of the cells is examined with the observance of boundary conditions providing
the preservation of their close packing. The inclusion is assumed to be rigid, and the matrix properties are described by
equations of the linear hereditary viscoelasticity theory. The formation of vacuoles is described by using the approach suggesting
that an initial debonding begins to propagate when the energy accumulated in the extended matrix reaches a value sufficient
to create a new interface. The heterogeneity of the composite is simulated by taking into account the variability of the local
filler concentration. Creep curves obtained for composite cells with different content of the solid phase are presented. Comparisons
between the numerical and experimental results show a satisfactory agreement.
Translated from Mekhanika Kompozitnykh Materialov, Vol. 44, No. 6, pp. 895–906, November–December, 2008. 相似文献
A procedure is developed for studying the interfacial friction in filled polymers. The paper presents results of experiments on physical models which represent an elastic matrix contacting with the friction surface. The friction law established experimentally was used to develop computational algorithms describing the processes of cyclic loading and relaxation in filled polymers in the case of permanent contact between the matrix and a hard inclusion and on detachment of the matrix from the inclusion. 相似文献
Due to the adsorption of biomolecules, the control of the biodistribution of nanoparticles is still one of the major challenges of nanomedicine. Poly(2‐ethyl‐2‐oxazoline) (PEtOx) for surface modification of nanoparticles is applied and both protein adsorption and cellular uptake of PEtOxylated nanoparticles versus nanoparticles coated with poly(ethylene glycol) (PEG) and non‐coated positively and negatively charged nanoparticles are compared. Therefore, fluorescent poly(organosiloxane) nanoparticles of 15 nm radius are synthesized, which are used as a scaffold for surface modification in a grafting onto approach. With multi‐angle dynamic light scattering, asymmetrical flow field‐flow fractionation, gel electrophoresis, and liquid chromatography‐mass spectrometry, it is demonstrated that protein adsorption on PEtOxylated nanoparticles is extremely low, similar as on PEGylated nanoparticles. Moreover, quantitative microscopy reveals that PEtOxylation significantly reduces the non‐specific cellular uptake, particularly by macrophage‐like cells. Collectively, studies demonstrate that PEtOx is a very effective alternative to PEG for stealth modification of the surface of nanoparticles.
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