Abstract:
Highly dispersed isotactic polypropylene (iPP)
nanocomposites were prepared by incorporating two different
sized Mg−Al LDH nanoparticles with different loadings from 1
to 10 wt % using a modified solvent mixing method. Larger
sized LDH nanoparticles (∼3−4 μm) were prepared from the
gel form of Mg−Al LDH, and the smaller sized nanoparticles
(∼50−200 nm) were prepared by sonication of as-synthesized
LDH particles. Such obtained LDH nanoparticles were
carefully characterized using wide-angle X-ray diffraction
(WAXD), transmission electron microscopy, and scanning
electron microscopy. WAXD and atomic force microscopy
results indicate that the LDH nanoparticles were highly dispersed in the iPP matrix. The influence of LDH nanoparticles size and
concentration on the thermal stability, spherulitic morphology, melting behavior, isothermal crystallization kinetics, and lamellar
structure of iPP were investigated. Incorporation of low loadings of sonicated LDH particles (e.g., 1−2.5 wt %) show substantial
effect on thermal stability, spherulite size, crystallinity, and crystallization half-time and lamellar morphology of iPP compared to
the pure iPP and that of nanocomposites with larger LDH particles with same loadings. The better nucleation ability of iPP in the
presence of sonicated LDH can be attributed to the high surface area of LDH nanoparticles along with its better dispersibility
within the polymer matrix. The incorporation of LDH nanoparticles does not change the crystallization growth mechanism and
crystal structure of iPP
