乙酸钠和柠檬酸钠对淀粉-海藻酸钠包装膜性能及结构影响

Effects of Sodium Acetate and Sodium Citrate on Properties and Structure of Starch-sodium Alginate Packaging Film

在玉米淀粉-海藻酸钠共混体系中,分别添加质量分数为0,0.05%,0.10%,0.20%,0.40%,0.80%的有机盐乙酸钠和柠檬酸钠至50 g/L淀粉悬液中,于90℃条件下搅拌40 min后流延成膜。测定包装膜机械性能、透光度、水溶性、水蒸气透过率,并用红外光谱(IR)、扫描电镜(SEM)、X-射线衍射(XRD)检测包装膜结构与形貌表征。结果显示,乙酸钠和柠檬酸钠的添加改变了包装膜机械强度,使膜透光度下降,水蒸气透过率、水溶性升高。SEM显示,添加乙酸钠包装膜表面凹凸不平,聚合大分子团分布不均匀;添加柠檬酸钠包装膜表面较为平整,有结晶现象,颗粒分布均匀。XRD分析表明,2种有机盐都增加了包装膜结晶度。

In the corn starch- alginate blend system,0,0.05%,0.10%,0.20%,0.40%,0.80% organic sodium acetate and sodium citrate are added to 50 g/L starch suspension, 90 ℃ stirring 40 min cast film forming. The mechanical properties,transmittance,water solubility and water vapor transmission of the packaging films are measured. The structure and morphology of the films are characterized by IR,SEM and XRD. The results show that the addition of sodium acetate and sodium citrate changed the packaging films’ mechanical strength,the transmittance decreased,the water vapor permeability and water solubility increased. SEM shows that the surface of sodium acetate film is irregular and unevenly distributed. The surface of sodium citrate film is smooth and crystallized,and the particles are evenly distributed. XRD analysis show that both organic salts increased the crystallinity of packaging films.