Thermal behavior and properties of chitosan fibers enhanced polysaccharide hydrogels

• Chitosan, in fiber form, was introduced into polysaccharide hydrogels.
• Strong interactions in hybrid hydrogels are systematically investigated.
• Dehydration activation energy decreases as the content of CSFs increases.
• Chitosan fibers improved hydrogels’ structural stability and storage modulus.

Composite hydrogel based on chitosan fibers (CSFs), high- and low-acyl gellan gum (HLG) was fabricated. The strong interactions between CSFs and HLG were confirmed by Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD) and thermogravimetric (TG) analysis. Differential scanning calorimetry (DSC) study shows that the dehydration activation energy decreases as the content of CSFs increases. The rheological measurement showed that the storage modulus of 2.0CSF–HLG (where 2.0 represents the mass ratio between CSF and HLG) hydrogels is 48 kPa at regular frequency of 1 rad/s, which is 1.8 times higher than that of HLG hydrogel. In addition, the SEM images demonstrated that 2.0CSF–HLG hydrogel exhibits three dimensional architectures with HLG attaching to CSFs. A weak swelling capacity of CSF–HLG hydrogels was observed, indicating fibroid CSFs would hinder the movement of HLG chain segments in solution.

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