Development of nanocomposite based on hydroxyethylmethacrylate and functionalized fumed silica: mechanical, chemico–physical and biological characterization (original) (raw)
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Poly(methyl-methacrylate) nanocomposites with low silica addition
The Journal of Prosthetic Dentistry, 2014
Statement of problem. Poly(methyl-methacrylate) (PMMA) represents the most popular current denture material. However, its major drawbacks are insufficient ductility and strength. Purpose. The purpose of this study was to improve the mechanical properties of PMMA in denture base application by adding small quantities of nanosilica. Material and method. Silica nanoparticles were added to the liquid component of the tested materials. The standard heat polymerizing procedure was followed to obtain 6 PMMA-silicon dioxide (/SiO 2) concentrations (0.023%, 0.046%, 0.091%, 0.23%, 0.46%, and 0.91% by volume). Microhardness and fracture toughness of each set of specimens was compared with the unmodified specimens. Furthermore, differential scanning calorimetry and scanning electron microscopy analyses were conducted, and the results obtained were correlated with the results of mechanical properties. Results. It was found that the maximum microhardness and fracture toughness values of the materials tested were obtained for the lowest nanosilica content. A nanosilica content of 0.023% resulted in an almost unchanged glass transition temperature (Tg), whereas the maximum amount of nanosilica induced a considerable increase in Tg. A higher Tg indicated the possible existence of a thicker interfacial layer caused by the chain immobility due to the presence of the particles. However, scanning electron microscopy results demonstrated extensive agglomeration at 0.91% nanosilica, which may have prevented the formation of a homogenous reinforced field. At a nanosilica content of 0.023%, no agglomeration was observed, which probably influenced a more homogenous distribution of nanoparticles as well as uniform reinforcing fields. Conclusions. Low nanoparticle content yields superior mechanical properties along with the lower cost of nanocomposite synthesis.
Biomaterials, 2004
A novel hydrogel based on 2-hydroxyethylmethacrylate and fumed silica nanoparticles is presented. The filler was mixed at increasing amount (3-40% w/w) to the organic monomer, before accomplish thermal polymerization. The hybrid composite materials obtained were characterized as far as concern the physical-chemical stability and sorption behaviour in water and water solutions. The novel hybrid hydrogels were compared to poly(hydroxyethylmethacrylate) (pHEMA) on cytocompatibility and ability to elicit cell adhesion and proliferation. These in vitro assays showed that the first ones were supporting cell growth better then pHEMA, moreover experiments on murine fibroblasts showed improved adhesion and proliferation with the increase of the nanomeric filler content. For a more physiological response, the in vitro tests should match biomaterials with cell populations typical of the implant site. Therefore, in view of future applications of these composites as scaffolds for bone engineering, in a successive step of our research we selected primary cultures of human osteoblasts (OB) as the most appropriate models to study the in vitro performance of these materials. The preliminary results obtained confirmed the remarkable improvement of OB adhesion properties of the new hybrids with respect to pure pHEMA. r
Nanocomposites based on polymethylmethacrylate and silica
2010
Nanocomposites based on polymethylmethacrylate and silica were synthesized by means of bulk polymerization. The morphology of the obtained polymer composites was studied by scanning electron microscopy. It was established that silica influences the mechanical and tribological properties of nanocom posites.
Modulus, Strength and Cytotoxicity of PMMA-Silica Nanocomposites
Coatings
Key advantages of Poly(methyl methacrylate)—PMMA for denture application are related to aesthetics and biocompatibility, while its main deficiency is related to mechanical properties. To address this issue, SiO2 nanoparticle reinforcement was proposed, containing 0 to 5% nanosilica, to form nanocomposite materials. Flexural strengths and elastic moduli were determined and correlated to nominal nanoparticle content and zeta potential of the liquid phase nanoparticle solutions. Another issue is the biocompatibility, which was determined in terms of cytotoxicity, using L929 and MRC5 cell lines. The addition of nanoparticle was proved to be beneficial for increasing flexural strength and modulus, causing a significant increase in both strength and moduli. On the other hand, the formation of agglomerates was noted, particularly at higher nanoparticle loadings, affecting mechanical properties. The addition of nanosilica had an adverse effect on the cytotoxicity, increasing it above the le...
Grafting of Poly(glycidyl methacrylate) onto Nano-SiO 2 and Its Reactivity in Polymers
In order to introduce reactive groups onto the surface of inorganic nanoparticles, which can take part in the in-situ reaction when being compounded with matrix polymers to produce nanocomposites, poly(glycidyl methacrylate) (PGMA) was grafted onto silane pretreated nano-SiO 2 by free-radical polymerization. This paper mainly studied the factors that influence the graft polymerization, including monomer concentration, initiator consumption, reaction temperature and reaction time. The reactive kinetics of the PGMA grafted on the nanoparticles with 4,4 0diaminodiphenylsulfone (DDS) in polypropylene (PP) or polystyrene (PS) matrices were evaluated by differential scanning calorimetry (DSC). It was shown that the appearance of PP or PS in the model composites did not change the overall curing reaction mechanism and the grafted nanoparticles gave a stable dispersion in the good solvent for the grafting chains.
Polymer, 2010
Biodegradable nanocomposites consisting of poly(3-caprolactone) (PCL) reinforced by PEGylated silica (polyethylene-glycol/SiO 2 ) nanoparticles were prepared by a melt-extrusion process. The PEGylated silica nanoparticles were prepared in a facile, one-pot synthesis process. Transmission electron microscopy (TEM) observations of the PEGylated silica nanoparticles inside the PCL matrix indicated that a homogeneous dispersion had been achieved. As a result, the storage modulus (E 0 ) in the rubbery plateau increased significantly with the filler contents at all temperatures studied, at values approximately 45% higher than the neat PCL, at a loading level of only 4 wt.%. In comparison, in the absence of polyethyleneglycol (PEG) the silica nanoparticles formed aggregates inside the PCL matrix, and the reinforcement was negligible. The results from X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FTIR) analyses identified the location of the PEG at the PCL/silica interface.