الفهرس 
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Abstract
The preparation of polymeric hybrid composite consisting of organic and inorganic nanofillers is of interest for industries like automotive, packaging and construction. In order to understand and predict the physico-chemical properties of these hybrid nanocomposites, it is necessary to fully understand the nature and properties of the applied nanofillers. In this study, the preparations of polypropylene hybrid nanocomposites consisting of different layered double hydroxide were investigated. Copper-aluminum layered double hydroxides (Cu-LDHs) and Nickel-aluminum layered double hydroxides (Ni-LDHs) were synthesized using co-precipitation method. Nanosized LDHs were organically modified by long chain sodium stearate. Polypropylene (PP)/ layered double hydroxides (LDHs) and Polypropylene (PP)/organically-modified layered double hydroxides nanocomposites (m.Cu-LDHs or m.Ni-LDHs) were prepared by the melt blending of the PP with either nanosized LDHs or m.LDHs without any other additives. The dispersion of the different percentages of LDHs into the polypropylene was investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). Thermal stability properties of PP/LDHs nanocomposites were also studied by thermogravimetric analysis (TGA). Mechanical properties of the PP/LDHs nanocomposites, tensile strength and modulus of elasticity were investigated. Ni-Al–LDH and Cu-Al–
SUMMARY
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LDH have been used as nanofillers and potential flame-retardant additives in
PP. The flammability properties were investigated using cone calorimeter test.
Intercalation of modified nanosized LDHs was determined by XRD in the
presence of stearate. Modified nanosized LDHs showed a good disperasbility in
PP matrix. Thermal stability of PP has been improved up to 6 % using
nanosized m.Ni-LDHs. Unmodified and modified nanosized LDHs decreased
the fire growth rate of PP from 10.8 kW/m2.sec to 4.1 kW/m2.sec and 4.5
kW/m2.sec. Band gap values were found to be 4.2, 3.5, 3.25 and 2.5 eV for
neat PP, PP/m.Cu-LDH 0.5% (wt/wt), PP/m.Cu-LDH 1 %(wt/wt) and
PP/m.Cu-LDH 1.5% (wt/wt) respectively. With increasing the percentage of
m.Cu-LDH added to PP, Eg shifted to be located in the semiconductor
materials range. The values of Eg are in the range reported for the high efficient
photovoltaic materials. So, the present composites could be considered
potential materials for harvesting solar radiation in solar cell applications
Keywords: Modified nanosized layered double hydroxide; polypropylene nano composites;
flame retardancy& Optical band gap.