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摘要
Oxidized starch gel material has become a hot material in fields such as food and biomedicine because of its advantages of hydrophilicity, chargeability, easy reaction and assembly in recent year. However, when used as a hot-extrusion 3D printing (HE-3DP) gel material, it has defects such as poor printability and low gel strength. This study investigated the influence of different chitosan addition amount on the rheological properties, printing formability and gel strength of oxidized starch-chitosan gel materials by adding different amounts of chitosan and utilizing non-covalent and chemical cross-linking between chitosan and oxidized starch. The results show that the oxidized starch-chitosan pastes exhibit typical shear-thinning characteristics. As chitosan is added in varying concentrations (0. 5%~2%), non-covalent interactions such as hydrogen bonding and electrostatic attraction lead to an increase in the viscosity of the system. The thixotropic property initially increases and then decreases, while the flow stress (τf) first decreases, and then increases; and the yield stress (τy) increases first and then decreases. Compared with oxidized starch gel, oxidized starch-chitosan gel has good printing formability. Especially when the amount of chitosan added is 1%, the composite gel has the best thixotropic property, the minimum flow stress (τf) and the largest yield stress (τy), so the printing formability and printing accuracy is the best. Additionally, due to the non-covalent interaction between chitosan and oxidized starch and the schiff base chemical cross-linking, the oxidized starch-chitosan gel forms a dense network structure to improve gel stability and gel strength significantly. These effects are more significant with a higher chitosan content. The results can provide a theoretical basis and technical support for the performance improvement of oxidized starch gel material and the design and application of oxidized starch-chitosan gel materials suitable for HE-3DP. ? 2024 South China University of Technology.
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