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Silica‐based self‐healing microcapsules for self‐repair in concrete
Author(s) -
Tan Noel Peter Bengzon,
Keung Lok Hang,
Choi Wing Ho,
Lam Wai Chak,
Leung Hei Nga
Publication year - 2016
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.43090
Subject(s) - materials science , polymerization , self healing , composite material , fourier transform infrared spectroscopy , scanning electron microscope , polyurethane , emulsion polymerization , monomer , chemical engineering , polymer , medicine , alternative medicine , pathology , engineering
New self‐healing material for concrete repair has been fabricated through microencapsulation of silica sol via interfacial polymerization of poly(urea‐urethane). Smooth, uniform, and spherical capsules of 60–120 µm sizes were synthesized and optimized by studying the emulsification and polymerization steps of its synthesis. A hydrophile–lyophile balance (HLB) value of 3.0–5.0 and a rotational speed of 500 rpm were necessary to produce a stable emulsion system of silica sol in surfactants. The polymerization speed of 900 rpm and the methylene diisocyanate (MDI) monomer content of 15 wt % were both significant in getting the right size and smoothness of the microcapsules. With this method and cheap healing agents, industrial scale‐up is highly possible. The viscoelastic properties of the microcapsules were examined, and further characterizations were carried out through scanning electron microscopy, energy dispersive X‐ray spectroscopy, and Fourier transform infrared spectroscopy. After healing the microcracks in concrete, the results showed that the significant increase of compressive and bending strengths manifested the self‐healing ability of the microcapsules in concrete. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 43090.