Preparations and properties of maleic acid and maleic anhydride functionalized multiwall carbon nanotube/poly(urea urethane) nanocomposites

The functionalized multiwall carbon nanotubes (MWNTs) have been prepared by free radical reaction with maleic acid and maleic anhydride. The functionalized MWNT was further blended with poly(dimethylsiloxane) (PDMS) based Poly(urea-urethane) (PUU). Both maleic acid modified MWNT (Maa-g-MWNT) and maleic anhydride modified MWNT (Mah-g-MWNT) showed enhanced dispersion compared with that of pristine MWNT and PUU. The content of maleic acid or maleic anhydride in modified MWNT was quantitatively characterized by TGA. The ratio of disorder band (D-band) to graphite band (G-band) of MWNT was investigated by Raman spectroscopy. Furthermore, the morphology of MWNT/PUU nanocomposites was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The mechanical property, molecular mobility, and electromagnetic shielding effectiveness (EMI) of MWNT/PUU nanocomposites were discussed in this study. For MWNT/PUU nanocomposites containing 5 phr functionalized MWNT, the maximum microwave absorption was −19.2 dB for Maa-g-MWNT/PUU nanocomposites and was −22 dB for Mah-g-MWNT/PUU nanocomposites.