有机肥基可降解膜成膜助剂的优选及膜性能研究

Preferred Film-Forming Additives and Film Properties of Organic Fertilizer-Based Biodegradable Films

研发可降解膜对于缓解由传统塑料膜引起的土壤环境污染具有重要意义.在不同的生物可降解材料中,利用有机肥中丰富的纤维素、半纤维素和腐殖酸为骨架材料制备生物可降解膜成为一种新的选择,而成膜助剂是有机肥制备可降解膜的关键.为了探究膜制备过程中成膜助剂对膜性能的影响,分析成膜助剂对有机肥可降解膜的作用机理以及膜的降解规律,以海藻酸钠、丙三醇、戊二醛和羧甲基纤维素钠为成膜助剂,通过正交设计试验,以拉伸强度、断裂伸长率与气体透过性为指标,对成膜助剂最佳浓度进行优化.结果表明:当海藻酸钠、丙三醇、戊二醛和羧甲基纤维素钠添加量(以质量分数计)分别为0.70%、1.00%、0.20%和1.00%时,有机肥可降解膜的综合性能最佳,其中机械性能中的拉伸强度为16.88 MPa、断裂伸长率为28.47%,氨气和二氧化碳透过系数分别为1.23×10^(−11)和1.03×10^(−11)g·m/(m^(2)·d·Pa).光谱学分析结果表明,成膜后羟基、羧基、醛基等官能团含量和结晶度均有增加,因而实现了松散有机肥成为稳定性的可降解膜材料.土壤掩埋试验结果表明,膜材料降解过程符合二级降解动力学模型,降解速率常数为0.004,32 d降解失重率为58.97%,具有较好的降解性.因此,成膜助剂对有机肥制备的可降解膜机械性能和气体透过性影响显著,且降解性良好,在农业生产领域具有一定的实用价值.

The research and development of biodegradable film is of great significance to alleviate the pollution of soil environment caused by traditional plastic mulch.Among different biodegradable materials,it is a new choice to use cellulose,hemicellulose and humic acid which are abundant in organic fertilizer to prepare biodegradable film,and the film-forming additives are the keys to prepare biodegradable films successfully by using organic fertilizers as the raw materials.In order to study the influence of film-forming additives on the membrane performance during film preparation,the mechanism of action of film-forming additives on organic fertilizer degradable films and the degradation pattern of the films were analyzed.In this study,sodium alginate,propanetriol,glutaraldehyde and sodium carboxymethylcellulose were used as film-forming additives,and the concentrations of film-forming additives were optimized in terms of tensile strength,elongation at break and gas permeability through orthogonal design tests.The results showed that the best overall performance of the films was achieved when the contents of sodium alginate,propanetriol,glutaraldehyde and sodium carboxymethylcellulose were 0.70%(mass percentage),1.00%,0.20%and 1.00%,respectively.The tensile strength of the optimized product was 16.88 MPa,and the corresponding break elongation was 28.47%.Furthermore,the ammonia and carbon dioxide permeability coefficients of the optimized product were 1.23×10^(−11) and 1.03×10^(−11) g·m/(m^(2)·d·Pa),respectively.Spectral analysis results showed that the contents of functional groups such as hydroxyl,carboxyl,aldehyde groups and the crystallinity increased after the film was formed,resulting in a stable degradable film prepared from loose organic fertilizers.The soil simulation experiments showed that the degradation process of the degradable film conformed to the second-order degradation kinetic model,the degradation rate constant was 0.004,and the 32nd day degradation weight loss was 58.97%,which is a good degradability.The present study shows that the addition of film-forming additives has a significant effect on the mechanical properties and gas permeability of the organic fertilizer degradation film,which has good degradation properties and practical value in agricultural production.