Effect of chitin nanowhiskers on structural and physical properties of konjac glucomannan hydrogels nanocomposites.

Konjac glucomannan (KGM) has been widely studied because of its excellent gelling properties. However, the freeze-thaw stability and weak gel strength significantly limit its industrial application. To solve these issues, we innovatively introduced oxidized chitin nanowhiskers (O-ChNWs) under heating and alkaline conditions, thus achieving the improvement of the properties of KGM gels. In this study, rheological measurement and textural analysis were performed to verify the physicochemical properties of the as-prepared KGM/O-ChNWs. Results showed that the KGM/O-ChNWs dispersion exhibited a typical non-Newtonian pseudoplastic fluid behavior and the mechanical property of the gels enhanced with the amount of O-ChNWs increasing. Also, Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) was applied to elucidate the interaction between KGM and O-ChNWs. It showed that both strong hydrogen bonding and amide bonds could be formed to stabilize the KGM/O-ChNWs structure. Additionally, morphological images show that O-ChNWs can influence the original KGM structure and then form more uniform pores. Furthermore, thermogravimetric (TGA) analysis and freeze-thaw measurement demonstrated that O-ChNWs could obviously improve the thermal and freeze-thaw stability of the nanocomposite gels. Taken together, this current work can provide new insights into existing KGM gel systems and stimulate the development of additional KGM-based nanocomposite gels with the desired mechanical strength and freeze-thaw stability. [Display omitted] • O-ChNWs acted as nano-filler of KGM and had strong hydrogen bond with KGM. • Microstructure and gel properties of KGM nanocomposite gels depended markedly on O-ChNWs concentration. • The introducing O-ChNWs improved freeze-thaw stability of the KGM-based nanocomposite gels. [ABSTRACT FROM AUTHOR]