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Coupling of chemical cross-linking, swelling, and phase separation in microencapsulation

発表形態:
原著論文
主要業績:
主要業績
単著・共著:
共著
発表年月:
2002年
DOI:
会議属性:
指定なし
査読:
有り
リンク情報:

日本語フィールド

著者:
Dobashi, T., Furukawa, T., Ichikawa, K., Narita, T.
題名:
Coupling of chemical cross-linking, swelling, and phase separation in microencapsulation
発表情報:
Langmuir 巻: 18 号: 16 ページ: 6031-6033
キーワード:
概要:
抄録:
In the interfacial polymerization of poly(urea-urethane) membranes that result in the formation of microcapsules, the mechanism of microencapsulation can be complex. To clarify this process, a series of organic solvents with different degrees of compatibility between the solvent and the polymer, consisting of diethyl phthalate (DEP), dibutyl phthalate (DBP), and dioctyl phthalate (DOP), was used to study the polymerization of triisocyanate in both film and microcapsule formation. The physical properties of both the films and of the microcapsules were then determined by using a combination of differential scanning calorimetry, optical microscopy, and atomic force microscopy. The glass transition temperatures of films with limiting amounts of DFP, DBP, and DOP and without the organic solvent were, respectively, 98, 115, 123, and 124 �C. The triisocyanate + DOP system had a lower critical solution temperature of about 5 �C, with a two-phase domain structure for the membrane synthesized with DOP above the critical solution temperature. The shape of the microcapsules was found to be spherical, biconcave, and biconcave with a hump for compositions with weight fraction of DOP, ws, being 0, 0.3-0.5, and 0.78, respectively. By taking into account the compatibility between the solvent and the polymer, the combined results suggest that chemical cross-linking, swelling, and phase separation can be coupled to control the mechanism in microencapsulation of poly(urea-urethane) membranes to form microcapsules. A homogeneous elastic membrane is formed with organic solvents that are compatible with the wall-forming monomers, whereas the membrane becomes brittle and heterogeneous with less compatible solvents due to phase separations.

英語フィールド

Author:
Dobashi, T., Furukawa, T., Ichikawa, K., Narita, T.
Title:
Coupling of chemical cross-linking, swelling, and phase separation in microencapsulation
Announcement information:
Langmuir Vol: 18 Issue: 16 Page: 6031-6033
An abstract:
In the interfacial polymerization of poly(urea-urethane) membranes that result in the formation of microcapsules, the mechanism of microencapsulation can be complex. To clarify this process, a series of organic solvents with different degrees of compatibility between the solvent and the polymer, consisting of diethyl phthalate (DEP), dibutyl phthalate (DBP), and dioctyl phthalate (DOP), was used to study the polymerization of triisocyanate in both film and microcapsule formation. The physical properties of both the films and of the microcapsules were then determined by using a combination of differential scanning calorimetry, optical microscopy, and atomic force microscopy. The glass transition temperatures of films with limiting amounts of DFP, DBP, and DOP and without the organic solvent were, respectively, 98, 115, 123, and 124 �C. The triisocyanate + DOP system had a lower critical solution temperature of about 5 �C, with a two-phase domain structure for the membrane synthesized with DOP above the critical solution temperature. The shape of the microcapsules was found to be spherical, biconcave, and biconcave with a hump for compositions with weight fraction of DOP, ws, being 0, 0.3-0.5, and 0.78, respectively. By taking into account the compatibility between the solvent and the polymer, the combined results suggest that chemical cross-linking, swelling, and phase separation can be coupled to control the mechanism in microencapsulation of poly(urea-urethane) membranes to form microcapsules. A homogeneous elastic membrane is formed with organic solvents that are compatible with the wall-forming monomers, whereas the membrane becomes brittle and heterogeneous with less compatible solvents due to phase separations.


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