硅藻土添加对HDPE/LDPE基抗氧化活性膜性能的影响

The Influences of Diatomite Addition on the Performance of HDPE/LDPE Antioxidant Active Film

目的研究硅藻土添加量对HDPE/LDPE基抗氧化活性膜的拉伸强度、阻氧阻湿性能、热封性能等物理性能及抗氧化剂在活性膜中释放性能的影响。方法以硅藻土为活性膜内层的无机填料,乙烯-醋酸乙烯共聚物(EVA)为无机填料增容剂,槲皮素为抗氧化剂,采用共挤流延法制备外层为HDPE、内层为LDPE的HDPE/LDPE基多层抗氧化活性膜,通过改变内层膜中硅藻土的添加量调整槲皮素从活性膜中的释放。结果添加硅藻土的质量分数为0,1%,2%,3%,4%时,槲皮素扩散系数D(cm2/s)分别为5.91×10-13,2.30×10-11,1.59×10-11,2.44×10-11,3.22×10-11。随着硅藻土的增加,活性膜的热封强度逐渐减小,拉伸强度先增加后减小,透氧系数、透湿系数均呈先减小后增加的趋势。结论硅藻土的添加对活性膜的拉伸性能、阻氧阻湿性能影响较小,显著削弱了活性膜的热封性能,使达到平衡时槲皮素的最终释放量增加;硅藻土的添加及添加量的改变能有效调整槲皮素的释放。

This paper aims to study the influence of diatomite addition and amount on the release property of antioxidant and the physical properties such as tensile strength, oxygen and moisture barrier properties, heat sealing properties of HDPE/LDPE antioxidant active film. HDPE/LDPE antioxidant active film was prepared by co-extrusion casting method. The outer layer was HDPE, and the inner layer was LDPE with the diatomite as inorganic filler and ethylene-vinyl acetate copolymer（EVA） as the compatibilizer for the inorganic filler, and quercetin as the antioxidant. The release rate of quercetin was adjusted through changing the diatomite amount in the inner layer. As a result, when the diatomite amount was 0, 1%, 2%, 3%, 4%, the 2diffusion coefficient D（cm/s） of quercetin were 5.91× 10-13, 2.30× 10-11, 1.59× 10-11, 2.44× 10-11 and 3.22× 10-11 accordingly. With the increase of diatomite amount, the heat seal strength gradually decreased, tensile strength firstly increased and then decreased, and oxygen and moisture permeability coefficient were first decreased and then increased. In conclusion, the addition and amount of diatomite have few effects on the tensile properties, oxygen and moisture barrier properties of the film, but significantly weaken the sealing performance of the active film. Besides, the addition of diatomite made the final release amount of quercetin increased, and changing the amount of diatomite can effectively adjust the release rate of quercetin.