For slow release of tea tree oil (TTO), TTO were encapsulated by urea-formaldehyde (UF) resin via in situ polymerisation. The effects of curing time and drying condition on particle size, and TTO loading of the TTO/UF microcapsules were investigated. The results indicated that TTO/UF resin microcapsules with curing time of 80 min had narrow size distribution and good wall cover. Drying at ambient was better to maintain the TTO content than drying at oven. The loading of TTO with curing time of 80 min can be up to 45 wt.% of the mass-proportion to the prepared microcapsules, and more than 90 wt.% of the loaded TTO could be sustainably released in about 5 days. Moreover, the release kinetics of TTO/UF microcapsules was well described by Ritger-Peppas model, revealing non-Fickian diffusion. Promisingly, TTO/UF microcapsules with good stability can be used as a slow release vehicle for antibacterial application.

中文翻译：

---

通过原位聚合及其缓慢释放的模型制备TTO / UF树脂微胶囊。

为了缓慢释放茶树油（TTO），通过原位聚合将TTO用脲醛（UF）树脂封装。研究了固化时间和干燥条件对粒径的影响以及TTO / UF微胶囊的TTO负载量。结果表明，固化时间为80 min的TTO / UF树脂微胶囊具有较窄的粒径分布和良好的壁覆盖率。在室温下干燥比在烘箱中干燥更好地保持TTO含量。固化时间为80分钟的TTO的负载量可以占所制备微胶囊质量比例的45％（重量），并且在约5天之内可以持续释放90％（重量）以上的TTO。此外，Ritger-Peppas模型很好地描述了TTO / UF微胶囊的释放动力学，揭示了非菲克扩散。很有希望