不同增塑剂对结冷胶薄膜性能的影响

Effects of different plasticizers on properties of gellan gum films

为开发新型食品包装材料,以结冷胶为成膜基质,以甘油、丙二醇和聚乙二醇400为增塑剂,采用流延法来制备生物可降解包装薄膜,研究膜的微观结构、热稳定性、力学性能、透光性能、水蒸气及氧气透过率。采用红外光谱、X-射线衍射和电镜扫描对3种增塑剂与结冷胶之间的相容性进行分析。结果表明:以甘油为增塑剂,成膜性能最佳,丙二醇次之。热重分析表明,3种基膜在0~100℃表现出良好、均一的热稳定性,热稳定性依次为:丙二醇、甘油、聚乙二醇400。物理学性能测试分析表明,3种增塑剂的添加均会提高基膜的厚度、断裂延伸率、抗拉强度、水蒸气和氧气透过率,降低膜的透光性能。采用甘油添加量为40%(质量分数,结冷胶基)来制备薄膜时,抗拉强度最大为32.46 MPa,断裂延伸率最大为8.33%,氧气透过率最大为2.11 cm^(3)·mm/(m^(2)·d·atm),水蒸气透过率最大为2.45×10^(-10) g/(m·s·Pa),透光率最大为91.8%,满足包装薄膜的性能需求,为新型可降解包装膜的制备及应用提供理论基础。

To develop new food packaging materials,gellan gum was used as film-forming base with glycerol,propylene glycol,and polyethylene glycol 400 as plasticizers and biodegradable packaging films were prepared by casting method.The microstructure,stability,mechanical properties,light transmission,water vapor,and oxygen permeability of the films was investigated.Compatibility analyzed between the three plasticizers and gellan gum by infrared spectroscopy,X-ray diffraction,and electron microscope scanning showed that glycerol>propylene glycol>polyethylene glycol 400.Thermogravimetric analysis showed that the three base films exhibited good and uniform thermal stability in the temperature range of 0-100℃and propylene glycol>glycerol>polyethylene glycol 400.The physical performance test analysis showed that the addition of the three plasticizers increased the thickness,elongation at break,tensile strength,water vapor,and oxygen permeability rates of the base film,and reduced the light transmission performance.When the film was prepared by adding 40%glycerol(mass fraction,gellan gum base),the maximum tensile strength was 32.46 MPa,the maximum elongation at break was 8.33%,and the maximum oxygen permeability rate was 2.11 cm^(3)·mm/(m^(2)·d·atm),the maximum water vapor transmission rate was 2.45×10^(-10) g/(m·s·Pa),and the maximum light transmission rate was 91.8%,which met the performance requirements of packaging films.These results indicate a theoretical basis for the preparation and application of new degradable packaging films.