Upcycling prawn shells: Chitosan–carbon nanotube nanocomposites with boosted magnetic and electrical properties

Multi-walled carbon nanotubes (MWCNTs) were successfully synthesized and functionalized by chemical vapour deposition and acid reflux methods, respectively. Chitosan (CTS) was prepared by a chemical extraction method from waste prawn shells. Various weight fractions of functionalized multi-walled carbon nanotubes (f-MWCNTs) have been used as reinforcing agent in CTS biopolymer matrix. Fourier transform infrared spectroscopy analysis was done, which confirms the presence of absorption bands of the various functional groups of chitin, CTS, and MWCNTs. Raman spectra revealed the quality of MWCNTs, the extent of their functionalization, and the quality of nanocomposites. The X-ray diffraction analysis showed the distinctive peaks for f-MWCNTs’ and also revealed the formation of CTS/f-MWCNTs nanocomposites. Transmission Electron Microscopy (TEM) analysis also exhibited that the CTS/f-MWCNTs nanoparticles have a well-defined crystalline structure. The highest coercivity and magnetization (Ms) of the CTS/5%f-MWCNTs nanocomposite are 602 Oe and 0.1202 emu/g, respectively that have been enhanced by 3.83 and 5.27 times compared to the pure CTS respectively. It showed that the conductivity is getting higher with the addition of f-MWCNTs in the CTS matrix. CTS/5% f-MWCNTs composites exhibit the highest conductivity than other composites and the conductivity of CTS/5% f-MWCNTs composite is 4.0×10⁻⁴ S/m.