Active compounds encapsulation in polymeric carriers is a widely used technology as it protects and improves the physical characteristics of the active compound and controls its delivery. Polymeric microcapsules (MCs) effectiveness is strongly related to the barrier properties of the polymeric shell, which in turn are dependent on the shell molecular weight and crystallinity. Therefore, the aim of this study was to tailor these two MCs attributes via solid state polymerization (SSP) and to examine SSP efficiency as a post-encapsulation modification step. More specifically, double emulsion-solvent evaporation technique was efficiently applied to prepare unloaded PLA MCs of four different molecular weights which were then subjected to SSP in a fixed bed reactor under nitrogen flow. Post-polymerization reactions occurred in the shell of the microcapsules as evidenced by the increase of the molecular weight. In parallel, SSP on the MCs served as a post-crystallization step resulting in higher melting properties, i.e. melting temperature and crystallinity. Adapting the SSP process from the conventional bulk polymer scale to the microcapsule geometry scale was herein proved feasible to overcome any drawbacks of the conventional encapsulation stage and to produce customized application products.

活性化合物封装在聚合物载体中是一项广泛使用的技术，因为它可以保护和改善活性化合物的物理特性并控制其传递。聚合物微囊（MCs）的有效性与聚合物壳的阻隔性能密切相关，而阻隔性能又取决于壳的分子量和结晶度。因此，本研究的目的是通过固态聚合（SSP），并检查SSP的效率，作为封装后的改性步骤。更具体地说，有效地应用了双重乳液-溶剂蒸发技术来制备四种分子量的未负载PLA MC，然后在氮气流下在固定床反应器中对其进行SSP处理。分子量增加证明了聚合后反应发生在微胶囊的壳中。同时，MC上的SSP用作后结晶步骤，从而导致更高的熔融性能，即熔融温度和结晶度。在本文中证明了将SSP方法从常规的本体聚合物规模调整到微囊几何尺寸的可行性是可行的，以克服常规封装阶段的任何缺点并生产定制的应用产品。