Preparation and properties of UV curable room temperature repair bio‐based poly(siloxane‐urethane) coating

Abstract In order to improve the problems of traditional self‐healing polyurethane coating, such as harsh curing and repair conditions, poor hydrophobicity, thermal stability and human affinity, the prepolymer was synthesized by bio‐based polyol castor oil (CO), self‐made alkyl aryl modified silicone polyol (SiOH) and isophorone diisocyanate (IPDI), and dimethylglyoxime (DOU) was used as chain extender containing dynamic imine bond, methacrylic acid 2‐(tert‐butylamino)ethyl ester (MABE) was used as a capping agent containing acrylate and high steric hindrance amino structure, and a UV curable room temperature repair bio‐based poly(siloxane‐urethane) coating (PUESi) was prepared by stepwise polymerization. In this article, the effect of the amount of DOU on the properties of PUESi was studied. The results showed that PUESi with different dosages of DOU could achieve self‐healing at room temperature. The maximum repair efficiency of full cut could reach 91.8%, and the scratch repair efficiency could reach 99.3%; The contact angle meter and synchronous thermal analyzer proved that the introduction of SiOH significantly improved the hydrophobicity, oil repellency and thermal stability of PUESi. The water contact angle increased from 78° to 104°, the oil contact angle increased from 63° to 91°, and the 5% thermal decomposition temperature increased from 179 to 196°C. The coating has broad application prospects in the fields such as antifouling and anticorrosion, building material protection, and automotive instruments.