Matsunami Yuki, Ichikawa Kimio
Fujinomiya Laboratory, Fuji Photo Film Co. Ltd, 200 Onakazato, Fujinomiya, 418-8666, Shizuoka, Japan.
Int J Pharm. 2002 Aug 21;242(1-2):147-53. doi: 10.1016/s0378-5173(02)00138-2.
A series of poly(urea-urethane) microcapsules containing phthalate derivatives as a core material were prepared by an interfacial polymerization process in order to investigate the structural formation mechanism. Scanning electron microscopy (SEM) analysis for the cross sections of microcapsules revealed the systematic formations of porous structures followed by the formation of core/shell structures. Critical values of the core oil content for the formation of porous and core/shell structures were obtained from SEM results and the critical values were found to be proportional to the solubility parameters of core materials. Dynamic mechanical measurements indicated an amorphous structure of wall membrane and the glass transition temperature was found to decrease with increasing the core oil content suggesting a plasticizing effect. The surface amount of the core oils absorbed in the wall membrane was estimated using time of flight secondary ion spectroscopy analysis and found to increase with increasing the oil content before reaching constant. This tendency was interpreted in terms of the structural formation of the microcapsules. The results obtained in the present investigation were reasonably understood on the basis of swelling theory of wall membrane and the Flory-Huggins interaction parameters of the systems were discussed.
为了研究结构形成机理，通过界面聚合法制备了一系列以邻苯二甲酸酯衍生物为芯材的聚（脲 - 聚氨酯）微胶囊。对微胶囊横截面的扫描电子显微镜（SEM）分析揭示了多孔结构的系统形成，随后是核/壳结构的形成。从SEM结果获得了形成多孔和核/壳结构的芯油含量的临界值，并且发现临界值与芯材的溶解度参数成比例。动态力学测量表明壁膜为无定形结构，并且发现玻璃化转变温度随着芯油含量的增加而降低，这表明存在增塑作用。使用飞行时间二次离子光谱分析估计了壁膜中吸收的芯油的表面量，发现在达到恒定之前随着油含量的增加而增加。这种趋势根据微胶囊的结构形成进行了解释。基于壁膜的溶胀理论，合理地理解了本研究中获得的结果，并讨论了体系的弗洛里 - 哈金斯相互作用参数。
