We have successfully synthesized magnetic chitin (MCH) by incorporating iron oxide nanoparticles into biodegradable and abundantly naturally available chitin by the coprecipitation method. X-ray diffraction (XRD) characterization revealed formation of cubic inverse spinel structure of Fe3O4 nanoparticles. In addition to this, other characterization studies like energy dispersive X-ray analysis (EDX) and vibrating sample magnetometry (VSM) were also performed to have an insight into the compositional and functional nature of the structure. A detailed spectroscopic study of complex impedance and dielectric constant for a wide frequency range of ~1 Hz to 10 MHz at discrete temperatures ~300–400 K has been performed by us for the first time on MCH in order to understand various relaxation processes. From permittivity, we have estimated the height of the potential barrier to be ~95.8 ± 0.3 meV. Impedance measurements yielded an activation energy of ~35.85 meV. Thermogravimetric analysis (TGA) of the sample showed exceptionally high thermal stability of the sample with percentage of residual mass at 800 ℃ being ~73% in MCH, which is quite high in comparison to the pristine chitin. An S shaped curve obtained through VSM measurement confirmed the superparamagnetic nature of the nanocomposite. The study assumes significance in the present scenario of rising awareness about the environment and demand to explore alternative green materials with numerous biomedical/environmental applications ranging from drug delivery vehicles in COVID-19 treatment to food packaging.

The authors conducted free radical polymerization using an initiator to synthesize a copolymer of isobornyl methacrylate—Acrylonitrile (I/A). The reactivity ratios of I (r1) and A (r2) monomers were determined as r1 = 1.63 ± 0.14, r2 = 0.61 ± 0.06 for linear KT (Kelen–Tudos) method and r1 = 1.58, r2 = 0.60 for the EVM (Error-in-Variable Method). We interpreted 1H and 13C{1H} NMR spectra of the I/A copolymers using DEPT-135 and 2D HSQC spectra. The α-CH3 carbon in the I-unit was identified and confirmed using a 2D HSQC NMR spectrum, up to the level of triad of compositional and configurational sequences. The CH (C14) and β-CH2 carbon peaks were also identified up to the triad level and higher, respectively. A 2D TOCSY spectrum revealed geminal and vicinal interactions within various CH and β-CH2 protons. A 2D HMBC NMR spectrum provided a complete assignment of the coupling between nitrile, carbonyl, and quaternary carbons with CH3 and CH2 protons.

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