International. The aim of a new study by scientists from Spain and Portugal was the development of water-based polyurethane-ureas added with plant extracts. The scientists examined different incorporation pathways and their influence on particle size, thermal, mechanical and antibacterial properties.
Polyurethane-ureas are a versatile family of polymers that can be used in a wide range of applications. Among them, polyurethane-urea dispersions in water (Wbpuu) are gaining relevance in the field of environmentally friendly products since their production process adopts ecological synthesis routes, avoiding the use of organic solvents. In addition, its water-based character can be exploited to incorporate various water-compatible ingredients capable of conferring functional properties on the final materials. Among them, plant extracts, which are known to have relevant bioactivities, can be seen as interesting candidates.
Therefore, 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% by weight) following different incorporation routes that include their addition during different phases of the production process (post-in-situ and pre-methods). Next, the films were prepared by solvent casting and were characterized from the point of view of physicochemical, thermal, mechanical, thermomechanical and antibacterial properties and morphologically.
The incorporation routes studied resulted in different collation mechanisms that varied from the extract positioned between the polyurethane-urea nanoparticles (post-method) to extract what was partially embedded within them (in-situ and pre-methods), which produced rigidity or flexibility in the films, improving in general the antimicrobial characteristics of the films after 4 days of incubation compared to the Wbpuu base, especially when the extract is embedded.
Source: https://www.sciencedirect.com/
