Synthesis and characterization of waterborne polyurethane and polyurethane-urea towards eco-friendly materials by cellulose nanocrystals and plant extracts incorporation

Abstract

In this work, environmentally friendly anionic waterborne polyurethane and polyurethane-urea dispersions were synthesized in order to prepare films by casting. The effect of molar composition and synthesis route were analyzed on the waterborne polyurethane and polyurethane-urea dispersions, as well as the properties of films. Furthermore, these dispersions were used for the preparation of new eco-friendly materials. In this way, cellulose nanocrystals were isolated for the preparation of nanocomposite films. The effect of matrix nature, cellulose nanocrystals content and their incorporation route were analyzed in the final properties of the nanocomposites. Moreover, electrospun nanocomposite mats were prepared from waterborne polyurethane-cellulose nanocrystals dispersions using poly(ethylene oxide) as polymer template. The effect of varying the nanoreinforcement content and incorporation route was analyzed in the morphology and surface behavior of mats. In a second section, extracts containing bioactive compounds from two plants (Salvia officinalis L. and Melissa officinalis L.), were obtained for being incorporated to polyurethane-urea dispersions in order to confer antimicrobial properties. Three different incorporation routes were designed for the incorporation of different extract contents. Polyurethane-urea dispersions containing plant extracts were characterized and films were prepared. The final properties of films were analyzed and antimicrobial tests were carried out against Gram positive Staphylococcus aureus and Gram negative Escherichia coli and Pseudomonas aeruginosa bacteria.