酰氯接枝淀粉缓释肥包膜材料的制备与表征

目的]探讨淀粉的接枝改性对缓释肥包膜材料疏水性及尿素缓释性能的影响。方法]以吡啶为溶剂,采用硬酯酰氯对淀粉进行接枝改性,并通过流延法制得一系列接枝改性膜。采用元素分析法对所得接枝改性膜的取代度进行分析,采用FT-IR、扫描电镜对其结构形貌进行表征,通过接触角、尿素渗透性及生物降解性等测试对改性膜性能进行分析。结果]随着接枝取代度的增加,改性膜的接触角迅速增大,达110°以上,疏水性增强。7 d尿素累积渗透率下降,最低达23.6%。接枝改性后,膜材的生物降解速率下降,60 d的降解率由纯淀粉的86.0%降至29.3%。结论]通过调节反应时间及酰氯与淀粉的添加比例,获得不同缓释性的酰化淀粉膜,以满足不同农作物在不同生长周期对养分的要求。

Preparation and Characterization of Acyl Chloride Grafted Starch Coating Materials of Fertilizers

Objective] To study the effect of grafting modification of starch on slow release property of urea and hydrophobicity of the membrane material.Method] A series of modified starch membrane, which modified by grafting with stearyl chloride, were prepared by the method of casting.The grafting degree, structure and morphology of as-prepared modified starch membrane were characterized by elemental analyzer, infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), respectively.And the properties of as-prepared modified starch membrane were characterized by contact angle analysis method, urea permeability and biodegradability under national conditions.Result] With the increase of grafting degree, the hydrophobicity increased and the contact angle increased rapidly, and reached to above 110 degrees.And the accumulated permeability of urea of 7 days decreased, with a minimum value of 23.6%.The biodegradation rate of the membrane decreased, and the degradation rate of 60 days decreased from 86% of pure starch to 29.3% after graft modification.Conclusion] The acylated starch films with different release properties, which can meet the different requirements of nutrient of different crops in different growth periods, were obtained by adjusting the reaction time and the proportion of added chloride and starch.