Morphology and Interfacial Action of Nanocomposites Formed from Ethylene-Vinyl Acetate Copolymers and Organoclays
writer：Zhang QL, Ma XY*, Wang YF, and Kou KC
keywords：polarity ,modifier and polymer matrixes,morphology , interfacial action ,nanocomposites,molecular dynamics (MD) , inverse gas chromatography (IGC),ethylene-vinyl acetate (EVA)
source：期刊
specific source：Journal of Physical Chemistry B, 2009,113(35), pp11898-11905
Issue time：2009年
The effect of the polarity of modifier and
polymer matrixes on the morphology and interfacial action of nanocomposites was
studied by molecular dynamics (MD) and inverse gas chromatography (IGC) based
on ethylene-vinyl acetate (EVA) /organic montmorillonite (OMMT), where vinyl
acetate (VA) concentrations are 9.3 and 18 wt %, respectively. It is found that
EVA with higher VA concentration displays a higher surface energy than that
with lower VA concentration. Modifier with two long alkyl tails will lower the surface
energy of montmorillonite (MMT) more effectively. Combined with transmission
electron microscopy (TEM) photography of EVA/OMMT nanocomposites, it is found
that the surface energies of organic montmorillonite and EVAs make great
contributions to the dispersion of the OMMT in polymer matrixes. OMMT modified
by two long alkyl tails displays weaker acid and base properties which will
have a better interaction with EVAs through acid-base
interaction. Molecular simulation (MD) proved that nonpolar interaction
determines the binding between EVAs and organoclays, otherwise electrostatic
interaction in polar polymer/organoclay systems. Binding energies were
calculated by MD, and the results show stronger interaction between20A(organoclay made from two long alkyl
tails surfactant) and EVA. Interfacial action between filler and polymer matrix
should be accountable for the mechanical properties of the nanocomposite