Preparation and properties of dialdehyde cellulose/polyvinyl alcohol composite hydrogel

Wheat straw was used as raw material to prepare lignin containing 2,3-dialdehyde cellulose (DAC) through sequential treatment of p-toluenesulfonic acid (p-TsOH), ultrasonication, sodium periodate oxidation. DAC was used as crosslinker to prepare 2,3-dialdehyde cellulose/polyvinyl alcohol (DAC/PVA) composite hydrogel through aldol condensation reaction. The microstructures, swelling properties, compression resistance and thermal stability of hydrogels were studied. Ampicillin (AP) was introduced to DAC/PVA composite hydrogel by embedding method to prepare DAC/PVA-AP hydrogel. Drug release process, release mechanism and antibacterial effect were studied as well. The results show that the microstructures of DAC/PVA composite hydrogels show a porous 3D network structure, and the crosslinking density increases with the increase of DAC. The water content and swelling property of composite hydrogel decrease with the increase of DAC. When the DAC concentration increases from 0.8wt% to 2.0wt%, the water absorption swelling rate decreases from 1823.54%±13.89% to 1105.41%±7.06%. The initial compressive strength of 1.0wt%DAC/PVA hydrogel reaches 5.765 MPa under 70% compression strain and present strong compression resistance. After sterilization at 121℃, the composite hydrogels can keep intact morphology, indicating that they have excellent high temperature resistance. The release model of DAC/PVA-AP hydrogel conforms to the Korsmeyer-Peppas model, and the sustained-release solution has a good antibacterial effect on the test bacteria. The DAC/PVA composite hydrogel prepared from wheat straw has a three-dimensional network structure, good mechanical properties and high temperature resistance, and has potential application the field of wound dressings.