Preparation and performance study of photo-initiated self-healing self-warning microencapsulated coated fabrics

Microcracks on the surface and inside inevitably occur during processing and use. The use of photo-initiated, self-healing, self-warning microcapsules to repair and monitor these microcracks is of practical importance to prolong the life of coated fabrics. In this work, the microcapsules (EP/FA/SiO2) with SiO2 as wall material, epoxy resin, fluorescent agent and cationic photoinitiator as core material were prepared using the interfacial in situ polymerization method. The self-healing self-warning PVC coated fabric was obtained by scraper coating method. The self-healing, self-warning and mechanical properties of the coated fabric were characterized. The results show that the microcapsules have an encapsulation efficiency of 79 % and a core-wall structure. The wall thickness is about 200 nm and the particle size is 1.7 μm. The microcapsules have excellent thermal stability below 320 °C. The microcapsules have good dispersion in the PVC coating surface and the repair agent has good wettability in the PVC coating surface. When the cuts expand, the previously embedded microcapsules break open and release the fluorescent active ingredient and the repair agent of the capsule core. Under UV light irradiation, the scratches may show a yellow fluorescence to indicate the location of the damage to the coating. The repair agent (epoxy resin) fills the cuts and then polymerizes with the cationic photoinitiator under UV light. As the exposure time increases, the cut gradually narrows and the strength of the coated fabric increases. After 36 h of UV exposure, the cut disappears and the strength of the coated fabric is 742 N, reaching the strength (768 N) of the fabric before scratching. This indicates that the coated fabric has a good photo-initiated self-healing effect.