Non-isocyanate polyurethane nanoparticles prepared by nanoprecipitation

The present study describes the preparation of non-isocyanate polyurethane nanoparticles by nanoprecipitation. The protocol consists in the dropwise addition of a previously prepared poly(hydroxy)urethane (PHU) organic solution into permuted water. PHU synthesis was performed by polyaddition reaction between a bio-based bis-(cyclic carbonate) monomer and a diamine, in solution and without catalyst, in a reproductible manner. The control of the polymer purity was crucial for the nanoprecipitation step and final nanoparticle characteristics. PHU chemical structure was thoroughly examined by 1H and 13C NMR. Molar masses were determined by MALDI-TOF and SEC. PHU thermal behaviour was investigated by TGA and DSC. Size and size distribution of nanoparticles obtained by nanoprecipitation were determined by DLS. The effect of polymer concentration in the organic phase, nature of the organic solvent and solvent-to-water volume ratio on the colloidal characteristics was investigated. PHU nanoparticle ageing behaviour was also studied.