Development of waterborne polyurethane-ureas added with plant extracts: Study of different incorporation routes and their influence on particle size, thermal, mechanical and antibacterial properties

Abstract

A B S T R A C TPolyurethane-ureas are a versatile family of polymers which can be employed in a wide range of applications. Among them, waterborne polyurethane-urea (WBPUU) dispersions are gaining relevance in the field of environmentally-friendly products since their productive process adopts green synthesis routes, avoiding the use of organic solvents. Furthermore, their waterborne character can be exploited to incorporate several water compatible ingredients able to confer functional properties to the final materials. Among them, plant extracts, which are known to have relevant bioactivities, can be viewed as interesting candidates. Therefore, in this work, two extracts known to present antimicrobial activity (Melissa officinalis L. and Salvia officinalis L.) were obtained by the infusion method and incorporated into the WBPUU (1, 3 and 5 wt%) following different incorporation routes comprising its adding during different phases of the productive process (post-, in-situ and pre-methods). Thereafter films were prepared by solvent-casting and characterized from the viewpoint of physicochemical, thermal, mechanical, thermomechanical and antibacterial properties and morphologically. The studied incorporation routes resulted in different intercalation mechanisms that varied from extract positioned among the polyurethane-urea nanoparticles (post-method) to extract partially embedded inside them (in-situ and premethods), which produced stiffening or flexibilizing effects in the produced films, enhancing in general the antimicrobial characteristics of films after 4 days of incubation comparing with base WBPUU, especially when the extract is embedded.

Influence of the addition of PEG into PCL‐based waterborne polyurethane‐urea dispersions and films properties

“…Similar thermal and mechanical behaviors were found for PCL100 and PCL95PEG5 WBPUUs. Comparing these values with those reported in previous works, one can notice higher values of Young modulus (23 ± 2 MPa against 6.4 ± 0.4 MPa), as well as similar strain at breaks (842 ± 102% vs. 891 ± 51%) . Other systems presenting higher amount of PEG exhibited similar Young modulus values as well as similar strain at break suggesting that the addition of only 3.4 wt % is enough to modify the behavior of the WBPUU.…”

“…In this way, the aim of this work was to determine the minimum PEG content in the synthesized WBPUU dispersion at which the properties of the final material change significantly, in order to demonstrate that the incorporation of different contents of PEG could be a suitable strategy to modulate the final properties of the dispersions and films. The synthesized dispersions could be employed in VOCs free coatings or adhesives, as well as base for the preparation of environmentally friendly functional coatings by means of the incorporation of water dispersible nonentities and additives . As explained before, the solid content of the dispersion is a key parameter in order to obtain either dispersions or gels, hence in this work the solid content was maintained low enough (25 wt %) to avoid gelification so as to study both dispersions and films.…”

“…The synthesized dispersions could be employed in VOCs free coatings or adhesives, as well as base for the preparation of environmentally friendly functional coatings by means of the incorporation of water dispersible nonentities and additives. [38][39][40] As explained before, the solid content of the dispersion is a key parameter in order to obtain either dispersions or gels, hence in this work the solid content was maintained low enough (25 wt %) to avoid gelification so as to study both dispersions and films. The particle size, distribution, and stability of the colloidal dispersions as well as the physicochemical, thermal, mechanical, and thermomechanical properties, morphology, and hydrophilicity of the films were evaluated and compared to the literature.…”

Design of a Waterborne Polyurethane–Urea Ink for Direct Ink Writing 3D Printing

“…Additionally, the nature of this kind of water-based systems allowed the incorporation of hydrophilic nanoentities such as cellulose derivatives [17] and/or plant extracts [18,19], which can also be used as natural surfactants for other nanoentities like graphene [20]. This incorporation of nanoentities can lead to the realization of a final printed piece with different properties or even new functionalities.…”

Cellulose and Graphene Based Polyurethane Nanocomposites for FDM 3D Printing: Filament Properties and Printability

“…Salvia spectrum can also be seen on Figure 2 . Salvia extract spectrum shows two main characteristic bands, a wide band between 3700–3000 cm −1 , attributed to the hydroxyl groups in the salvia structure and a wide band between 1800–1500 cm −1 , related to an overlapping of the carboxylic group band and the C=C aromatic rings [ 54 ].…”