Effect of organomodified nanoclay in poly (3-hydroxybutyrate) (PHB)-, epoxidized natural rubber (ENR-50) and PHB/ENR-50 blend nanocomposites
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Date
2014-09
Authors
Salehabadi, Ali
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Abstract
This treatise investigates the influences of alkyl ammonium organomodified
montmorillonite (MMT) on the property profiles of biodegradable polyester, PHB,
an epoxy modified natural rubber, ENR-50, and their respective PHB/ENR-50
blends. Several compositions of nanohybrids were prepared by dispersion of MMT
nanolayers in polymer solution employing solvent casting technique. Surface
morphology and interfaces characteristics of different nanohybrids were investigated
using polarized optical microscopy (POM) and scanning electron microscopy (SEM).
Structural morphology over interfaces analysis indicated a proper distribution of
MMT in polymer matrix by either reducing or complete dissolution of interface sizes
and dimensions. Thermal stability and thermal transition of the systems were
characterized by thermogravimetry (TG-DTG) and differential scanning calorimetry
(DSC), respectively. The thermal stability of different systems varied upon addition
of MMT. MMT nanolayers exhibited either catalytic or barrier effect in thermal
profiles of nanohybrids. The ability of silicate layers of MMT to interact via
intercalation or exfoliation and also structural rearrangement of PHB crystals were
investigated using X-ray diffraction analysis. The reflected peaks intensities and the
basal spacing varied upon addition of MMT. The (020) and (110) orthorhombic
crystalline planes of PHB have changed in position and d-spacing upon addition of
both ENR-50 and MMT. FTIR spectra provide further evidence that supports the
reaction possibilities through the hydrogen bonding and ring opening reaction of
epoxy groups. The reaction mechanisms were proposed. The Kissinger plots showed
that the nanohybrids exhibited a decrease in degradation activation energy (Ed). The
nanomechanical study of these samples indicates changing in hardness (H) and
elastic modulus (E) upon increasing MMT content in the sample.
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Keywords
Organomodified Nanoclay