INTEMA   05428
INSTITUTO DE INVESTIGACIONES EN CIENCIA Y TECNOLOGIA DE MATERIALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Synthesis of nanocomposites based on methacrylate monomers containing in-situ formed silver nanoparticles
Autor/es:
S.V. ASMUSSEN; C.I. VALLO
Lugar:
Dresden
Reunión:
Conferencia; 8th ECNP International Conference on Nanostructured Polymers and Nanocomposites; 2014
Resumen:
Silver nanoparticles were in-situ synthesized in methacrylate monomers by chemical reduction of silver nitrate (AgNO3, from Aldrich) with hydroquinone methylether (MEHQ). The methacrylate monomers were 2,2-bis[4-(2-methacryloxy ethoxy)phenyl]propane (BisEMA, from Esstech, Essington, PA) and a 70:30 weight ratio of 2,2-bis[4-(2-hydroxy-3-methacryloxyprop-1-oxy)phenyl]propane (from Esstech, Essington,PA) and triethylene glycol dimethacrylate, from Aldrich) (BisGMA). The monomers contain MEHQ as inhibitor, to increase the shelf life, preventing premature polymerization of the monomer. The methacrylate monomers containing the reducing agent (MEHQ ), silver nitrate and ethanol absolute were mixed at 80 °C using magnetic stirring until complete evaporation of the solvent. No stabilizing agent was used. The AgNPs/monomer suspensions were yellow resins stable at room temperature. Both BisTEG and BisEMA monomers prevent both oxidation and coalescence of the nanoparticles which contributes to long-time stability of the suspensions. The suspensions of AgNPs were examined with a spectrometer (1601 PC, Shimadzu). UV-vis spectra showed plasmon resonance absorption bands centered at 410 nm. TEM images  showed that the size of the AgNPs was in the 20-60 nm range. From UV-vis and TEM images it emerges that the methacylate monomers used in this study are good stabilizers of the AgNPs. This is attributed to strong interaction between the silver ions and the monomers through functional groups present in BisEMA and BisTEG. Uniformly dispersed ultrafine particles in a polymer matrix may not be easily achieved by incorporating pre-made nano-size particles into a polymer due to the easy agglomeration of nanoparticles and high viscosity of monomers and polymers. Conversely, the in-situ formation of AgNPs in methacrylate results in a uniform dispersion of nanoparticles. The AgNPs/monomer suspensions can be polymerized by thermal or phothochemical means.