Physically Crosslinked Composite Hydrogels of Hemicelluloses with Poly(vinyl alcohol phosphate) and Chitin Nanowhiskers

Abstract

Hydrogels have been widely studied as tissue engineering scaffolds due to their swelling capabilities in water and other physical properties. In this study, phosphatized PVAs of varying degrees were prepared by esterification of phosphoric acid, and a freeze-thaw technique was introduced to fabricate hydrogels from hemicelluloses, poly(vinyl alcohol phosphate) (P-PVA), and chitin nanowhiskers. The obtained hydrogels were characterized by Fourier transform infrared (FT-IR) spectrometry, scanning electron microscopy (SEM), X-ray diffraction (XRD), and CP/MAS 13C nuclear magnetic resonance; their swelling properties and compressive strength were also determined. The repeated freeze-thaw cycles induced physically crosslinked chain packing among the three polymers by hydrogen bonds. The results showed that the hydrogels possessed higher swelling ratio and mechanical strength when the PVA was phosphatized by phosphoric acid and urea and more hydroxyl groups were introduced into the polymer matrices. This suggested that hydrogels with good mechanical properties were prepared successfully by the freeze-thaw technique.

Keywords

• Hemicelluloses
• Hydrogel
• Poly(vinyl alcohol phosphate)
• Freeze-thaw
• Chitin nanowhiskers