Chemistry Reference
In-Depth Information
A solid-phase polymers deformation description is always in the center of
attention. Models, considering the indicated polymers as homogeneous (uni-
form) viscoelastic body or taking into consideration structure heterogeneity
on the basis of “effective homogeneity” hypothesis are known. This hypoth-
esis assumes the possibility of heterogeneity consideration with the help of
one effective elasticity modulus introduction [1]. Both approaches result to
multiparameter integral models, the application of which in practice is dif-
ficult enough, particularly in the range of finite strains. Such models com-
plexity is predetermined to a considerable extent by nonlinear hereditary
elasticity calculus formal application, which is assumed as an obligatory one
at polymer materials deformation analysis [2]. The first from the described
approaches was used for polyethylenes and nanocomposites on its basis,
filled with ogranoclay, creep processes description [3, 4].
Unlike the approach, averaging mechanically heterogeneous body prop-
erties, it has been offered to conduct analysis of polymers deformation by
another mode of their structural heterogeneity consideration [5, 6]. Struc-
ture heterogeneity or dynamical state in polymer materials bulk results to
sharply differing deformation ability of these materials various structural
components. Then it can be supposed that exactly deformation heterogene-
ity of polymer material structure results mainly to its viscoelastic properties
nonlinearity [6]. The authors of Ref. [7] conducted the description of poly-
ethylene and nanocomposites on its basis creep process with their structural
heterogeneity appreciation within the frameworks of cluster model of poly-
mers amorphous state structure [8].
Within the frameworks of the indicated structural model [8] it is supposed
that semicrystalline polymer at all and polyethylene in particular consists of
crystalline and amorphous phases, in addition the latter includes local order
domains (clusters) and loosely packed matrix, which for polyethylenes in
the case of testing at room temperature is in devitrificated state. It is obvious,
that the last circumstance defines small elasticity modulus and high com-
pliance of loosely packed matrix [6]. At introduction into polymer matrix
organoclay to the mentioned above structural components two another ones
are added: actually nanofiller and interfacial regions. Both semicrystalline
polymer and nanocomposites on its basis have heterogeneous structure, in
which devitrificated loosely packed matrix compliance will be essentially
higher than the remaining structural components. This means that at loading
firstly loosely packed matrix will be deformed and semicrystalline polymer
or nanocomposite on its basis compliance will be defined by this very com-
