Synthesis and characterization of polyfunctional aziridine/polyester microcapsules by multiple emulsion-solvent evaporation method

Abstract

Polyfunctional aziridine/polyester microcapsules as control-release waterborne cross-linker were synthesized by multiple emulsion-solvent evaporation method. The results show that, a lower surface free energy with shell polyester is more favourable for the formation of microcapsules. Full encapsulating microcapsules are synthesized with the polyester with a surface free energy of 34.5 mJ/m². Shell-to-core feeding mass ratio has a significant influence on the morphology and core content of the resulting microcapsules. Well defined spherical microcapsules with uniform shell thickness and core content at around 22% are produced at a shell-to-core mass ratio of 1:1. When 2.5% of colloid stabilizer is used, hollow spherical microcapsules are obtained. A high solvent evaporation rate results in wrinkling and porosity of the microcapsules, and an evaporation rate equivalent to solvent elimination in about 2 h provides a uniform rate of surface hardening. The characterization of the microcapsules by SEM and FTIR demonstrates that polyfunctional aziridine is encapsulated at the centre of the microcapsule. The microcapsules synthesized can be broken at a high shear rate.

Keywords

microcapsule / aziridine / polyester / multiple emulsion-solvent evaporation

References

[1] KondoA.Microcapsule processing and technology [M], 1979, New York, Marcel Dekker: 165

[2] SparksR. E.Microencapsulation [M], 1989, New York, Marcel Dekker: 255

[3] BenitaS.Microencapsulation: Methods and Industrial applications [M], 1996, New York, Marcel Dekker: 12

[4] ArshadyR.Microspheres, microcapsules and liposomes [M], 1999, London, Citrus Books: 25

[5] AoZ., YangZ., WangJ. F., ZhangG. Z., NgaiT.. Emulsiontemplated liquid core-polymer shell microcapsule formation [J]. Langmuir, 2009, 25: 2572-2574

[6] BlaiszikB. J., CarusoM. M., McIlroyD., MooreJ., WhiteS. R., SottosN. R.. Microcapsules filled with reactive solutions for self-healing materials [J]. Polymer, 2009, 50: 990-997

[7] GHOSH S K. Functional coatings by polymer microencapsulation [M]. Wiley-VCH, 2006: 282.

[8] HoganJ. E., AultonM.Pharmaceutical coating technology [M], 1995, London, Taylor & Francis: 215

[9] OlivierP. H., NicolasJ., LahoussineO.. Real-time monitoring of fragrance release from cotton towels by low thermal mass gas chromatography using a longitudinally modulating cryogenic system for headspace sampling and injection [J]. Anal Chem, 2010, 82(2): 729-737

[10] HuS. H., TsaiC. H., LiaoC. F., LiuD. M., ChenS. Y.. Controlled rupture of magnetic polyelectrolyte microcapsules for drug delivery [J]. Langmuir, 2008, 24(20): 11811-11818

[11] UttamM., SatishP.. Dual drug delivery microcapsules via layer-by-layer self-assembly [J]. Langmuir, 2009, 25(18): 10515-10522

[12] StevenA. C., StephenL. W.. Modeling approach to assess clustering impact on release rates of pesticides from microencapsulated products [J]. J Agric Food Chem, 2009, 57(12): 5443-5451

[13] BrownE. N., KesslersM. R., SottostN. T.. In situ poly(urea-formaldehyde) microencapsulation of dicyclopentadiene [J]. J Microencapsulation, 2003, 20: 719-730

[14] XuX., DongJ., LiJie.. Analysis of volatile components in propolis by solid-phase micro-extraction and GC-MS [J]. Food Industry Technology, 2008, 29(5): 57-60

[15] XiangZ. Y., LuY. C., ZouY., GongX. C., LuoG. S.. Preparation of microcapsules containing ionic liquids with a new solvent extraction system [J]. Reactive and Functional Polymers, 2008, 68: 1260-1265

[16] YuanL., LiangG.-zheng.. Synthesis and characterization of microencapsulated dicyclopentadiene with melamine-formaldehyde resins [J]. Coll Poly Sci, 2007, 285: 781-791

[17] RuleJ. D., SottosN. R., WhiteS. R.. Effect of microcapsule size on the performance of self-healing polymers [J]. Polymer, 2007, 48: 3520-3529

[18] YangH., WuG., ChenH. Z., WangM.. Oil core/polymer shell microcapsules prepared by solvent evaporation technique [J]. Sciencepaper Online, 2009, 4(4): 288-291

[19] LiM., RouaudO., PonceletD.. Microencapsulation by solvent evaporation state of the art for process engineering approaches [J]. International Journal of Pharmaceutics, 2008, 363(1/2/3): 26-39

[20] TorzaS., MasonS. G.. Three-phase interactions in shear and electrical fields [J]. Journal of Colloid and Interface Science, 1970, 33(1): 67-83