?Functionalization of polyurethane nanocomposites with either gold or silver nanoparticles?

AGUSTINA B. LEONARDI, MARÍA E.V. HORMAIZTEGUI, VERÓNICA L. MUCCI, IGNACIO DELL´ERBA, M. ALEJANDRA FANOVICH, MIRTA I. ARANGUREN.

Mar del Plata

Congreso; XVI Simposio Latinoamericano de Polímeros y XIV Congreso Iberoamericano de Polímeros; 2018

SLAP

The aim of this work is the functionalization of films based in polyurethanes and polycaprolactone (PU-PCL) with gold nanoparticles (AuNPs) or silver nanoparticles (AgNPs). The PU-PCL films can be prepared from reactants obtained from renewable resources, giving a green alternative for the development of polymeric materials. They are used primarily as coating materials or adhesives for various substrates. AuNPs with an average diameter close to 5 nm could be uniformly dispersed in the PU-PCL, these AuNPs showed a significant photothermal effect even at very low concentrations when irradiated with a 532 nm laser at an irradiance close to 2 W/cm2 . On the other hand, AgNPs synthesized employing glycerol as both solvent and reducing agent with a diameter close to 23 nm were introduced in the PU-PCL film. This kind of NPs has very interesting antibacterial properties. EXPERIMENTAL METHODS The PU-PCL film was synthesized following the procedure of Hormaiztegui et al1 . Also the synthesis of AgNPs follows the procedure published by dell´Erba et al2 and the AuNPs procedure is also published3 . To prepare the films with different content of AuNPs or AgNPs, the solution that contains the NPs was mixed with the wet solution of PU and then dried at 40°C for 72 hours. Briefly, an aqueous solution containing PU-PCL was mixed with different amount of AuNPs (aqueous solution) or AgNPs (glycerol solution), the suspension is placed in glass Petri dishes coated with Teflon adhesive paper, then is heated at 40°C for 72 hours to remove all the solvent. The final materials were characterized by Differential Scanning Calorimetry, X-ray diffraction, Transmission electron microscope (TEM) and photothermal activity. RESULTS AND DISCUSSION Figure 1 shows four different composites obtained after the dry step (72h@40°C). The films with AuNPs or AgNPs seem very transparent without any signal of macro-aggregation of NPs. The amount of AgNPs or AuNPs is 0.5% w/w of silver or gold respect the PU-PCL bone. Figure 1.b represents the films with the same amount of glycerol that was introduced with the AgNPs, this was made to analyse separately the effect of the glycerol to the AgNPs. The Figure 1.c is the pure film, without any additive, it was prepared as a blank film for comparison purposes with the modified films. The most relevant feature of these films is their photothermal effect. Figure 2 shows the increase of temperature for the films irradiated with green light. An increase of more than 15ºC was observed for the sample with AuNPs, while in the case of AgNPs the rise was about 5ºC, both for 1 min of irradiation. Temperature attained asymptotic values after about 120 s irradiation, meaning that a steady state was attained. Cristallinity, physical aging and bactericidal properties of the films were also investigated. CONCLUSION Different materials based in PU-PCL were obtained changing the nature of the nanoparticles dispersed. The final properties of these materials may be interesting for a variety of applications. REFERENCES 1. Hormaiztegui et al, J.Appl. Polym. Sci. 2016. 133, 44207 2. I.E. dell´Erba, A. Y. Mansilla, C.E. Hoppe, R.J.J. Williams. J. Mater Sci. 2015. 51, 3817 3. V.J. Gandubert, R.B. Lennox. Langmuir 2005, 21, 6532.