With people's increasing awareness of environmental protection and health,low efficiency,large dosage and residual problems caused by widespread use of pesticides were concerned extensively.Pesticide microcapsules has shown lots of benefits to help improve the utilization rate of pesticide and achieve other aims as well.Using urea-formaldehyde resin as wall material and chlor-pyrifos (CPS)as core,the chlorpyrifos/urea formaldehyde resin microcapsules (CPS/UFMCs)was fabricated by in-situ polymeriza-tion.The effects of emulsifier sorts and dosage,pH,acidification time on particle size and distribution of chlorpyrifos/urea-formalde-hyde microcapsules (CPS/UFMCs)were studied,and the optimal process of CPS/UFMCs preparation was obtained.Moreover,the release performance and kinetics of the CPS/UFMCs prepared by optimal process was carried out to further investigate the loading capacity of microcapsules,encapsulation efficiency and release kinetics.The results showed that CPS/UFMCs had a narrow particle size distribution and a small average size with 3wt% sodium dodecyl sulfate(SDS)as emulsifier,the acidification time of 90 min,pH of 2.5,core/wall ratio of 1:3 and curing temperature of 60 ℃.In addition,the average size of CPS/UFMCs prepared with the opti-mization process was around 113 μm.Meanwhile,the CPS/UFMCs showed excellent loading performance with more than 62% CPS encapsulated and the CPS loading rate was more than 5 3%.Moreover,the investigation of release performance showed the chlorpyri-fos was released sustainably from the CPS/UFMCs,and more than 90% of the CPS encapsulated was released within 10 days.Subse-quently,the release kinetics was analyzed following mathematical models of Korsmeyer-Peppas equation and Higuchi equation.In the kinetic study,the results showed that the release process of CPS/UFMCs followed a Fick diffusion mechanism.Generally,the pre-pared CPS/UFMCs shows high drug loading,efficient encapsulation and excellent release performance,and can be further developed as a new type of pesticide formulation,which can provide theoretical support and practical reference for the development of new for-mulations of sustained-release pesticide.%随着人们健康与环保意识的不断加强,农药施用量大、效率低、高残留等问题日益受到人们的重视,对农药进行微胶囊化,有助于有效解决当前农药使用过程中所面临的问题.采用脲醛树脂作为壁材,以十二烷基硫酸钠为乳化剂,采用原位聚合法制备毒死蜱/脲醛树脂微胶囊.研究了乳化剂种类和用量、pH 值、酸化时间对微胶囊粒径及其分布的影响,并进一步探讨微胶囊的载药量、包封率及释放动力学.结果表明,采用3%(质量分数)的十二烷基硫酸钠为乳化剂,在酸化时间为90 min、酸化终点 pH 值为2.5、搅拌速度为1200 r/min、芯壁比为1:3、固化温度为60 ℃时,所制备的毒死蜱/脲醛树脂微胶囊的粒径分布窄,平均粒径约为113 μm,载药量达53%以上,包封率达62%以上.毒死蜱/脲醛树脂微胶囊的缓释性能及动力学研究结果显示,所制备的毒死蜱/脲醛树脂微胶囊的缓释效果明显,10天内能释放90%的药物,释放过程遵循 Fick扩散机理.可见,制备的毒死蜱/脲醛树脂微胶囊具有较高的载药量、较好的包封率以及缓释性能,可进一步开发为新型的农药制剂,并为开发缓释农药新剂型提供理论支持与实践参考.
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