Synthesis and characterization of environmentally-friendly waterborne poly (urethane-urea)s

In this work, corn-based 100% renewable carbon poly(trimethylene ether glycol) (P3MG), biodegradable and biocompatible poly(ethylene oxide) (PEO), 4,4'-diphenylmethane diisocyanate (MDI) and sodium 2,4-diamino-benzenesulfonate (SDBS) were used to synthesize novel biobased waterborne poly(urethane-urea) (WPUU) dispersions following an environmentally-friendly process, which avoids the use of organic solvent. The particle size of WPUU dispersions were determined by dynamic light scattering. The molar ratio of PEO/P3MG polyols was varied to identify the WPUU dispersion with the optimum equilibrium between renewable content and final properties. Increase of P3MG content in polyol mixture led to smaller particle size, what could be related to the hydrophilic character of PEO. All investigated WPUU films were characterized by means of their physicochemical, thermal and mechanical properties, as well as their morphology by atomic force, microscopy. Higher P3MG content in the WPUU films led to phase separation, at the nanoscale, higher glass transition temperature and T-1 endotherm temperature induced by the decrease in the hydrogen bonding between soft segment and hard segment. Moreover, higher P3MG content also resulted in higher modulus and elongation at break of the WPUU films. The present work highlights that waterborne poly(urethane-urea) dispersions with promising properties can be successfully prepared without using any catalyst and organic solvent.