Enhancing corrosion protection and luminescence in bio-based polyurethanes with fluorescent azine segments

Abstract

Bio-based polyurethanes (PUHs) derived from castor oil (CO) have emerged as promising materials due to their mechanical resistance and chemical inactivity; they have found tremendous application growth. The physical and chemical properties of polyurethane (PUH1–3) made from castor oil polyol (COP) and various polyols, such as 1,4-phenylene bis (2,4-dihydroxy benzylidene) azine (PDaz) or polyol of (epoxy castor oil (ECO) with PDaz) (Eaz) with hexamethylene diisocyanate (HMDI), are investigated and compared for their light emission and corrosion inhibition of mild steel (MS). Thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) are used to assess the differences in characteristics of different PUH forms. As a result of incorporating fluorescent hard segment azine PDaz into the polymer with various preparation strategies, luminescent non-conjugated polyurethane derivatives (PUHs) have been obtained straightforwardly in high yields, affording PUHs with advantageous emission and corrosion inhibition properties. According to the photoluminescence (PL) study, simply changing the strategy by which a fluorescent material is incorporated can either increase the intensity of the emitted color or cause it to shift to a longer wavelength as the PUHs exhibit excitation dependency behavior. The corrosion inhibition applications of PUHs were discovered to be very effective and varied depending on the procedure of molecule preparation. PUH3 exhibited a corrosion inhibition efficacy of about 97.6 %, and these compounds display properties of mixed-type corrosion inhibitors. The intriguing results of these compounds indicate promising coating applications characterized by outstanding strength and optimal adherence and open up promising avenues for using these compounds in luminous coatings.