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为明确15%甲霜灵微胶囊缓释剂配方及对烟草黑胫病的防治效果,采用原位聚合法制备并优化工艺,对获得的微胶囊进行释放规律研究及评价,并通过盆栽试验确定其防治效果。结果显示,微胶囊缓释剂最佳配方为(用质量分数表示):15%甲霜灵原药、27%二甲苯、2.5%农乳0203、2%氯化铵、4%乙二醇、0.2%黄原胶、2%NNO、47.3%水;制备优化工艺为:芯壁比例1∶1、搅拌速度400 r/min、调酸时间2 h、p H 4.5。所获得微胶囊制剂表面光滑致密无凹陷,大小均一,平均粒径12.93μm,包覆率93.58%。制剂有效成分在水相中缓慢释放,0~24 h为初期释放阶段,符合一级动力学方程,R2为0.9115,累计释放量达29.52%;24~360 h为匀速释放阶段,符合零级释放动力学方程,R2为0.9945,累计释放量为29.52%~93.22%;360 h后趋于稳定。施用所制备的15%甲霜灵微胶囊21 d后对烟草黑胫病的盆栽防治效果为82.2%,高于25%甲霜灵可湿性粉剂(75.7%)。表明制备的15%甲霜灵微胶囊具有良好的缓释性,对烟草黑胫病有较好的防治效果。
In order to clarify the formulation of 15% metalaxyl microcapsule sustained-release preparation and its control effect on tobacco black shank, the in-situ polymerization method was used to prepare and optimize the process, the release of microcapsules obtained was studied and evaluated, and determined by pot experiment Its control effect. The results showed that the optimum formulation of microcapsule sustained-release agent was (mass fraction): 15% metalaxyl, 27% xylene, 2.5% agrochemical 0203,2% ammonium chloride, 4% ethylene glycol, 0.2% xanthan gum, 2% NNO and 47.3% water. The optimal preparation process was as follows: the ratio of the core wall 1: 1, the stirring speed 400 r / min, the acid adjusting time 2 h, p H 4.5. The obtained microcapsule preparation has smooth and dense surface without depression and uniform size. The average particle size is 12.93 μm and the coverage rate is 93.58%. The effective components of the preparations were slowly released in the aqueous phase, 0 ~ 24 h for the initial release stage, in line with the first-order kinetic equation, R2 was 0.9115, the cumulative release of up to 29.52%; 24 ~ 360 h for uniform release stage, Kinetic equation, R2 is 0.9945, the cumulative release of 29.52% ~ 93.22%; 360 h later stabilized. The control efficacy of the prepared 15% metalaxyl microcapsule for 21 days on tobacco black shank was 82.2% higher than that of 25% metalaxyl WP (75.7%). The results showed that the prepared 15% metalaxyl microcapsules had good slow release and good control effect on tobacco black shank.