Abstract
Microcapsules containing reactive diisocyanate for use in self-healing polymers are successfully fabricated via interfacial polymerization of polyurethane (PU). Isocyanates are potential catalyst-free healing agents for use in humid or wet environments. The preparation of PU prepolymer and microencapsulation of isophorone diisocyanate (IPDI) healing agent are presented. Smooth spherical microcapsules of 40-400 μm in diameter are produced by controlling agitation rate (500-1500 rpm) according to a power law relation (n = -2.24). The PU shell wall thickness varies linearly with capsule diameter, such that the capsules wall thickness to diameter ratio is constant (∼0.05). High yields (∼70%) of a free-flowing powder of IPDI/PU capsules are produced with a liquid core content of 70 wt % as determined by TGA analysis. The microcapsules are stable with only ∼10 wt % loss of IPDI detected after 6 months storage under ambient conditions. Direct mechanical compression testing of microcapsules reveals a brittle fracture mode and normalized shell wall strength that varies with capsule diameter in a power law fashion (n = -0.77).
Original language | English (US) |
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Pages (from-to) | 9650-9655 |
Number of pages | 6 |
Journal | Macromolecules |
Volume | 41 |
Issue number | 24 |
DOIs | |
State | Published - Dec 23 2008 |
ASJC Scopus subject areas
- Organic Chemistry
- Polymers and Plastics
- Inorganic Chemistry
- Materials Chemistry