醛交联剂对壳聚糖复合膜性能的影响

以壳聚糖、聚乙烯醇、淀粉为原料，通过交联反应制备了壳聚糖复合膜，详细讨论了甲醛、戊二醛、乙二醛3种交联剂对膜性能的影响。结果表明：pH值对甲醛、戊二醛、乙二醛交联复合膜的性能均有显著的影响。强酸条件下反应速度快，相容性强。随着pH值的增加，拉伸强度和断裂伸长率都降低，甲醛和乙二醛交联膜的吸水率和透水率增加，而戊二醛交联膜的吸水率和透水率降低。随着pH的改变，戊二醛和乙二醛交联膜呈现不同颜色。醛的用量对膜的性能影响显著，随着醛用量的增加，拉伸强度和断裂伸长率先增后降，吸水率和透水率逐步降低，过量的醛会使膜的性能变差。醛的存在使膜的相容性得到改善。

Effect of Aldehydes on the Properties of the Composite Chitosan Films

The biodegradable composite films were prepared by cross-linked reaction with chitosan,polyvinyl alcohol(PVA) and starch as raw materials in this paper.The effects of cross-linking reagents such as formaldehyde,glutaraldehyde and glyoxal on the properties of the films during preparation were investigated in detail.Results showed that pH had great effect on the properties of cross-linked films.The reaction was quick and its compatibility increased under strong acidic condition.The tensile strength and the percentage of breaking elongation of the films decreased with the the pH,increase of pH high level also led to the increase of water-retaining rate and water-permeability rate of the films cross-linked by formaldehyde and glyoxal and the decrease of water-retaining rate and water-permeability rate of the films cross-linked by glutaraldehyde.The color of the films cross-linked by glutaraldehyde and glyoxal varied with the variation of pH.The properties of the films were also affected by the dosage of aldehydes.If the dosage in-(creased,) the tensile strength and the percentage of breaking elongation of the films increased firstly and then decreased,but the water-retainig rate and water-permeability rate decreased gradually.Superfluous aldehydes could impair the properties,whereas the existance of aldehydes is favorable to compatibility of the films.