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Scipediacontent: Scipediacontent moved page Draft Content 310949821 to Santamaria-Echart et al 2019a

2022-03-31T18:50:08Z

Scipediacontent moved page Draft Content 310949821 to Santamaria-Echart et al 2019a

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Created page with "== Abstract == The environmental awareness has promoted the development of new materials towards eco-friendly systems based on both, green synthesis processes as well as the..."

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== Abstract ==

The environmental awareness has promoted the development of new materials towards eco-friendly systems based on both, green synthesis processes as well as the renewable origin of the raw compounds. In this way, focusing on synthesis methods, the use of waterborne polyurethane-urea dispersions have gained attention due to their versatility leading to a wide variety of applications, broadening the range of applications. In addition, it is worth nothing that the dispersibility in water offers the possibility of incorporating soluble additives, such as plant extracts.
Therefore, in this work Melissa officinalis L. plant was selected in order to obtain bioactive plant extract, in order to be incorporated to a waterborne polyurethane-urea dispersion, varying their content as well as using three different incorporation routes. These dispersions were characterized and employed in the preparation of films which were analyzed from the viewpoint of physicochemical, thermal and mechanical properties, among others. Finally, the antibacterial properties of the films were analyzed after 1 and 4 days of incubation, where it was observed that the content and incorporation route of the extract influenced in the behavior of the films against common pathogens (Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa).

== Full document ==
<pdf>Media:Draft_Content_310949821native-articles-205.pdf</pdf>

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-<span style="text-align: center; font-size: 75%;">V: There was not bacteria growth on the surface or behind the film </span>
+<div class="center" style="width: auto; margin-left: auto; margin-right: auto;">
-X: There was bacteria growth on the surface or behind the film
+<div class="center" style="width: auto; margin-left: auto; margin-right: auto;">
 ==4 Conclusions==

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 ==1 Introduction==
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 The particle size distribution of the base WBPUU and Melissa-based WBPUU dispersions prepared by ''in-situ'' and by the pre-methods and distribution profiles are shown in '''Figure 1a'''. It was observed that, in general, and in comparison with the base WBPUU, the addition of extract to the WBPUU dispersion contributed to the broadening of the particle size distribution towards smaller particle sizes, acting as natural surfactants [8-10], favoring the dispersion formation and thus contributing to the achievement of smaller particles. However, the effect varied attending to the incorporation route due to the intercalation of the extract in among WBPUU nanoparticles, as can be seen in '''Figure 1b'''. In the case of ''in-situ'' method a progressive decrease in particle size was observed with increasing extract content, whereas by pre-method, the reduction in the particle size remained similar without relying on the extract content.
+[[File:Santamaria-Echart_et_al_2019a-image5-c.png|centre|600x600px]]
-[[Image:Santamaria-Echart_et_al_2019a-image5-c.png|600px]]
 <div class="center" style="width: auto; margin-left: auto; margin-right: auto;">
-<span style="text-align: center; font-size: 75%;">'''Figure 1.''' a) Particle size distribution of base WBPUU and Melissa-based WBPUU, b) Plant extract incorporation mechanisms</span></div>
+<span style="text-align: center; font-size: 75%;">'''Figure 1.''' a) Particle size distribution of base WBPUU and Melissa-based WBPUU, b) Plant extract incorporation mechanisms.</span></div>
 The thermal behavior of base WBPUU and WBPUU containing Melissa extract bioactive films was analyzed by DSC, and thermograms are shown in '''Figure 2a'''. Analyzing the base WBPUU film, it was appreciated that the polyurethane-urea film presented a T<sub>gSS</sub> around -50 °C, which remained similar in the bioactive films series. Furthermore, a broad transition related with the long range order of hard segment domains [11] was observed. In general, it was observed that Melissa extract incorporation favored the ordering of hard segment domains, resulting in a progressive increase of both, T<sub>mHS</sub> and ∆H<sub>mHS</sub> values, except in Melissa3<sub>in-situ</sub> sample. It is thought that in this case different extract intercalation mechanisms were developed.
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 <div class="center" style="width: auto; margin-left: auto; margin-right: auto;">
-<span style="text-align: center; font-size: 75%;">'''Figure 2.''' a) DSC thermograms and b) stress-strain curves of base WBPUU and Melissa-based WBPUU bioactive films</span></div>
+<span style="text-align: center; font-size: 75%;">'''Figure 2.''' a) DSC thermograms and b) stress-strain curves of base WBPUU and Melissa-based WBPUU bioactive films.</span></div>
 The antibacterial properties of the base WBPUU and Melissa-based WBPUU films were analyzed against ''Staphylococcus aureus'', ''Escherichia coli'' and ''Pseudomonas aeruginosa'' microorganisms. It was observed that after 1 day of incubation, the base WBPUU and Melissa-based WBPUU film presented bacteriostatic properties against the three bacteria, hindering their growth on the film. Nevertheless, none of the samples showed an inhibition zone. However, it was observed that after 4 days of incubation the base WBPUU sample did not show inhibitory power against none of the assayed bacteria, whereas the addition of Melissa extract, as well as the incorporation route, resulted in different behaviors, which could be related with the bioactive components constituting the extracts and the different intercalation mechanisms [12-13]. The obtained results are summarized in '''Table 1'''. In the case of ''Staphylococcus aureus'' bacteria, Melissa-based films maintained the bacteriostatic effect in all analyzed samples, attributable to the composition of the extract [14]. Instead, in the case of ''Escherichia coli'' and ''Pseudomonas aeruginosa'' bacteria, at 1 and 3 wt% of extract incorporated by pre-method was not enough in order to maintain the bacteriostatic effect of the film. It could be related with the intercalation of the extract among and inside the WBPUU nanoparticles, as well as in 1 wt% of extract against ''Pseudomonas aeruginosa'' bacteria, taking into consideration that these bacteria is a more resistant pathogen.

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Santamaria-Echart et al 2019a - Revision history

Materiales.Compuestos at 15:35, 24 October 2022

Materiales.Compuestos at 15:34, 24 October 2022

Scipediacontent at 10:39, 7 May 2022

Scipediacontent: Scipediacontent moved page Draft Content 310949821 to Santamaria-Echart et al 2019a

Scipediacontent: Created page with "== Abstract == The environmental awareness has promoted the development of new materials towards eco-friendly systems based on both, green synthesis processes as well as the..."