A novel synthesis route for waterborne polyisocyanate crosslinkers

The article introduces a novel synthesis route for waterborne polyisocyanate crosslinkers, addressing the growing demand for eco-friendly coatings. By designing a polyol intermediate containing both rigid moieties and carboxyl groups, the authors propose a one-step process that simplifies the traditional two-step method. This approach not only reduces energy consumption and cost but also improves the mechanical properties of the cured materials. The synthesis involves the esterification of trimethylolpropane with pyromellitic dianhydride, followed by polymerization with isophorone diisocyanate and blocking with methyl ethyl ketone oxime. The resulting waterborne polyisocyanate crosslinker, EWPI, is characterized using FT-IR, 1H-NMR, and thermal analysis techniques. The study also investigates the thermal properties, water dispersibility, and curing performance of EWPI, highlighting its potential for use in water-based coatings. The findings suggest that EWPI-1.8 offers superior comprehensive performance, making it a promising candidate for practical applications in the coatings industry.