Novel biodegradable nanocomposites containing multi wall carbon nanotubes (MWCNT) and poly(citric acid) (PCA) were successfully synthesized. For preparation of nanocomposites, MWCNT was opened using a mixture of sulfuric and nitric acid and its derivative containing – COOH and – OH functional groups was obtained. Polycondensation of monohydrate citric acid in the presence of functionalized MWCNT in the melting state was lead to nanotube-graft-poly(citric acid) (CNT-g-PCA) nanocomposites. The degree of polymerization of grafted hyperbranched poly(citric acid) onto the CNTs was controlled using CNT/citric acid ratio. The CNT-g-PCA were soluble in water freely and stirring their water solution and silver nitrate at room temperature lead to the CNT-g-PCA containing encapsulated silver nanoparticles in their polymeric shell. The structure of nanocomposites was characterized by TEM, DLS and spectroscopy methods.

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This study investigated the microwave absorption properties of core-shell composites containing; iron oxide decorated carbon nanotubes (CNTs) and silica (SiO2@Fe3O4-MWCNTs) with various thicknesses of silica shells (7, 20 and 50 nm). Transmission electron microscopy (TEM) and X-ray diffraction results confirmed the formation of these core-shell structures. Microwave absorption characterization of the samples at the ranging band under consideration (the X-band) showed increased absorption and shifting of the peaks to lower frequencies compared to the uncoated sample (Fe3O4-MWCNTs). The minimum reflection loss decreased with increasing SiO2 thickness. The minimum reflection loss of the composite with an optimized thickness of the silica shell (7 nm) exceeded -41 dB at 8.7-9 GHz.

A simple method has been developed for decorating multi wall carbon nanotubes (MWCNTs) with palladium and silver nanoparticles. In this method, MWCNT was opened and functionalized using nitric and sulfuric acid mixture. Then citric acid was polymerized in the presence of functionalized MWCNT and MWCNT-graft-poly (citric acid) (MWCNT-g-PCA) was obtained. The mixing of MWCNT-g-PCA with metal salts, such as palladium chloride and silver nitrate, leads to encapsulation of metal nanoparticles in the polymeric shell ( MWCNT/Pd, AgNPs ). The structure of MWCNT/Pd and AgNPs were characterized by usual spectroscopy and microscopy methods. The influence of nanoparticles on the electrical conductivity of MWCNT was also investigated.

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