A general and efficient route to covalently surface modification of MWCNTs by dopamine and their synergistic reinforcing effects in chitosan films

• Chitosan composites reinforced with MWCNTs-Dop were fabricated by solution casting.
• The MWCNT functionalization with dopamine improves the dispersity of MWCNT.
• The amine and hydroxyl groups of chitosan performs a hydrogen bonding with MWCNT-Dop.
• Effect of MWCNT-Dop on the thermal, and mechanical properties of chitosan was studied.

Multiwalled carbon nanotubes (MWCNTs) were considered as ideal filler in a polymer matrix due to their outstanding mechanical, electrical and thermal properties. This article describes a simple route to preparation of nanocomposite (NC) of chitosan and modified MWCNT by solution casting method. The process involves modification of MWCNT with dopamine and effects of modified MWCNT on dispersion, mechanical, thermal and morphological properties. Atomic force microscopy, Fourier transform infrared spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy, transmission electron microscopy, have been used to characterize the NCs. Scanning electron micrographs showed that in all of the NC films, except chitosan/MWCNT-Dop NC 7 wt%, MWCNT were dispersed homogeneously throughout the chitosan matrix. The XRD studies showed that the crystallinity of composite films decreases through hydrogen bonding between chitosan and MWCNT-Dop. The determination of mechanical and thermal properties demonstrated that the NC films exhibited significant enhancement in strength, modulus, and thermal stability compared with the pure chitosan.

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