Influence of the airflow and humidity on the chain aggregation during the film-formation in a flexible waterborne polyurethane formulation

Our results show how the environment's relative humidity strongly influences chain aggregation and chain interdiffusion due to extended plasticization of the hard segment at high humidities, while accelerated air flows are responsible for the occurrence of (partial) skinning. Interestingly, despite changes in the chain aggregation behavior and occurrence of skinning and skin breakup during drying resulting in higher roughness at the film surface, minor influence is registered on the bulk tensile properties of the films, revealing the resilient nature towards environmental conditions of these soft weakly phase segregating polyurethane systems.