Preparation of smart coatings with self-healing and anti-wear properties by embedding PU-fly ash absorbing linseed oil microcapsules

Abstract

The wear resistance of self-healing coatings embedded microcapsules, an important indicator to determine whether it can be used industrially, has received little attention. Herein, an innovative method has been developed to synthesize Polyurea (PU) microcapsules containing inorganic porous fly ash absorbing linseed oil (FA-oil) as core materials by interfacial polymerization to enhance the mechanical property of the microcapsules, thereby preparing the smart self-healing coatings with and wear resistance properties. Compared with the coatings embedded PU-linseed oil microcapsules without fly ash, the wear loss of the smart coatings embedded PU-FA-oil microcapsules was 2.4 mg/8 h, which was 61.5 times lower than the former. Moreover, it was 161.7 times lower than pure epoxy coatings without any microcapsules in anti-wear test. The results showed the addition of PU-FA-oil microcapsules significantly improved the wear resistance of the smart coatings. This main reason was that the inorganic porous fly ash had the characteristics of high hardness, super wear resistance, and the slow-release effect of FA-oil in friction. In self-healing of smart coatings test, the impedance modulus at 0.01 Hz of the cured region was very close to 109 Ω·cm2, which was further higher than the uncured region of 106 Ω·cm2 and only lower an order of magnitude than unscratched region of 1010 Ω·cm2. It indicated that the linseed oil released from PU-FA-oil microcapsules could still form film, healing the microcracks and cracks in smart coatings, and self-healing property of the smart coatings embedded PU-FA-oil microcapsules was unaffected.