Characterization of Nanoparticle-Polymer Nanocomposites

The presence of TiO nanoparticle in the low density polyethylene (LDPE) system decreased the overall crystallinity [37]. The decrease in crystallinity in the LDPE with respect to modified nanoparticle is comparatively lower than unmodified nanoparticle. It was suggested that the difference in surface energy between the immodified nanoparticles and the polymer is comparatively larger and may lead to strong immiscibility, which affects the crystallinity. 

Similarly, the coating of nanoparticles by surfactants or acid will also help in enhancing the dispersion of the nanoparticle in the polymer matrix. The CaCOj nanoparticle was coated with stearic acid [40]. The monolayer-coated particles are well dispersed in the polypropylene matrix. However, at higher particle concentration, a omerates still exist. 

The presence of coupling agent has also enhanced the dispersion of the nanoparticle in the polymer matrix. Incorporation of 5 wt% of trimellitic anhydride chloride-treated CaCO in PET and the coupling agent enhanced the dispersion of the nanoparticle in the polyethylene terephthalate matrix [63]. The coupling agent acts as bi-fimctional reactant. Anhydride ends xmdergo acid-base interactions with nanoparticle surface calcium ions, which may lead to better dispersion. 

Similarly, transmission electron microscopy studies are widely used in analyzing the dispersion of various nanoparticles in thermoplastic and thermosetting polymers. The dispersion of TiO nanoparticles in the thermoplastic polypropylene matrix prepared via melt blending technique was analyzed [67]. This tool is highly used to analyze the size and dispersion state of the particle dispersed in the polymer matrix. 

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