Green fluorescent waterborne polyurethane polyols

In this paper, we reported a series of green fluorescent flame-retardant waterborne polyurethane polyols. The polyurethane polyols were uniformly sized and possessed decent colloidal stability. Comparing to other reported products, our aqueous dispersions showed much stronger fluorescence intensity and greatly improved long-term stability, which were desired for practical applications. Small molecule conjugation units were gated into polyurethane chains via reaction between −OH of naphthalene and −NCO of diisocyanate, which restricts intramolecular rotation of naphthalene chromophores and non-radiative transition to enhance fluorescence intensity. The non-radiative transition and chromophore aggregation are weakened to hinder aggregation-caused quenching of chromophores to improve fluorescence by weak collision. This study has demonstrated a facile method to prepare waterborne polyurethane polyols, providing detailed explanation and guidance for related work in the future.