【摘要】 本文采用冷冻爆破法,将壳聚糖在LiOH/尿素溶液中溶胀,-60℃冷冻结冰,解冻搅拌后得到澄清壳聚糖溶液。壳聚糖碱溶液在硫酸/乙醇凝固浴中反相沉析,得到壳聚糖凝胶膜。此碱性溶剂体系法能避免壳聚糖降解,提高力学强度。力学测试结果表明,壳聚糖水凝胶膜拉伸强度为2.28MPa,最大拉伸应变(ε)达到226%。SEM观测到水凝胶微观结构类似蜂窝状,孔径均匀、致密,大小分布为50nm～5μm;XRD分析结果表明,碱溶液体系处理后壳聚糖晶型由α型转变成β型,结晶度降低。致密的结构和低结晶度是壳聚糖凝胶膜透明性和力学强度提高的重要原因。该性能优异的壳聚糖凝胶膜在关节软骨、创口敷料等方面有良好的应用前景。更多还原

【Abstract】 Traditional way to prepare chitosan hydrogel films is to dissolve chitosan in acetic acid or hydrochloric acid,then precipitate in alkali solution.Our research tried a new way to prepare chitosan hydrogel films in the following procedure: to make chitosan solution using an aqueous solution of LiOH/ urea as the solvent system,then to take freezing-blasting treatment to solvent chitosan,and to form hydrogel film through precipitatation in the sulphuric acid / ethanol solution.The chitosan hydrogel films made by the new method have high mechanical strength.Results by universal testing machine show that chitosan hydrogel film tensile stress strength is 2.28Mpa,which is much higher than chitosan hydrogel films prepared by traditional way.The tensile strain(ε) is 226%,which shows excellent flexibility.The structure of the hydrogel possesses well-distributed honeycomb-like shapes,which have pore size of about 50nm~5μm.The crystal shape has been changed from α-to β-and the degree of crystallinity decrease.The interesting structure and low crystallinity can explain the increase of mechanical strength.更多还原