Page 37 - Polymer-based Nanocomposites for Energy and Environmental Applications

16 Polymer-based Nanocomposites for Energy and Environmental Applications

1.7 Theories and simulating models for polymer
nanocomposite

Modeling strategy is always employed for better understanding and also predicting the
experimental behaviors of materials prior to practical evaluation. Valavala et al. [117]
illustrated the relation between different parts in modeling process (Fig. 1.6).
Obviously, there is a close relation between models, theory, and simulation.
Mechanical characteristics of nanostructured materials can be measured via the
computational techniques. The modeling methods cover a wide length range and time.
Computational chemistry methods are used for predicting the atomic structure, while
computational mechanics is carried out to anticipate the mechanical factors of mate-
rials and also engineering structure. Both the computational chemistry and mechanical
simulating techniques are defined on the basis of thoroughly established developed
principles in science and engineering. But there is no general modeling technique
for the intermediate length and time analogous to the smallest and largest time and
length scales; therefore, multiscale modeling methods are developed in order to pro-
vide simultaneously both advantages of computational chemistry and mechanics
methods to prognosticate the material and structure abilities.
Fig. 1.7 illustrates a diagram that describes the relationship of specific modeling
techniques in computational mechanics and chemistry.
Even though multistate molecular modeling (M3) is useful in many areas of mate-
rial science, it is specifically helpful in the polymer science because of its wide range
of phenomena at various scales and also its impacts on the ultimate material charac-
teristics [118-124]. In multiscale modeling, three important factors are required for the
accurate prediction of the abilities of polymer material systems including
(A) the relationship of which is assumed as continuum mechanics-based,
(B) potential selection for the molecular-level interatomic potential,
(C) procedure for the molecular modeling.
In this field, for polymer-based materials under the large changes, formulating the
constitutive law within a finite-deformation framework is essential for accurate
description of mechanical stress-strain feedbacks [125]. Yang et al. [126] developed
an efficient and extensible multiscale analysis to consider the carbon nanotube (CNT)
size and weakened bonding on the effective elastic stiffness of CNT/PNCs by using
continuum micromechanics and molecular dynamics (MD) simulations. Also, Pereira
et al. [118] represented the application of a multiscale molecular modeling method to

Measuremen Model Theory Simulation Experiment

Fig. 1.6 Developing process of theory experimental validation data.
Derived from Valavala PK, Odegard GM. Modeling techniques for determination of
mechanical properties of polymer nanocomposites. Rev Adv Mater Sci 2005;9:34–44.