Fluorine-Free, Biobased Antismudge Polyurethane Coating with Enhanced Flame Retardancy

Abstract

Antismudge coating materials are generally synthesized by using petroleum-based polyols and fluorinated compounds, which are harmful to the environment and human health. Thus, researchers are more inclined to develop polyurethane (PU) coating from biobased polyols and fluorine-free materials. Here, silicone-containing diol was used with soybean oil polyol (SOP) to produce a PU coating. The chemical inertness to acid, base, and salt, along with the nonstick properties of silicone, would help achieve the desired properties of the antismudge PU coating. Metal (stainless steel) and wood coupons (oak wood) were coated with this synthesized coating material and tested to study the chemical resistance along with an ink test. In addition, the coated metal coupons were subjected to water and solvent drops more than 50 times without any discernible influence on the metal. Contracted ink was used to write 1000 times on the coating, and ink was easily erased by a paper napkin. The coating material was also subjected to a burning test, and the ignition time increased in direct correlation with the proportion of the Si-containing diol. More than twice as long as the control sample, 11 s were required for Si-40 wt % to start burning. The weight loss achieved with Si-40 wt % PU coating material is only 1%. Furthermore, after being immersed in water for 24 h, these PU coating materials failed to demonstrate any discernible impact. With a water contact angle of 95°, this PU coating material is hydrophobic. The coatings were exhibited to test their ability to absorb solvents as well as heat analysis. All available results suggest that environmentally friendly materials are promising candidates for future surface protective coatings.