A biocompatibility study of a reinforced acrylic-based hybrid denture composite resin with polyhedraloligosilsesquioxane.
ABSTRACT Acrylic-based denture materials have several common weak points, such as shrinkage after curing, lack of strength and toxicity. In order to solve these problems, we adapted a hybrid system using acrylic polymer and polyhedraloligosilsesquioxane (POSS). The aim of the study was to investigate the biocompatibility of a reinforced acrylic-based hybrid denture composite resin with POSS. Specimens of a novel polymeric denture base resin, in which POSS was used to partially replace the commonly used base monomer, were fabricated. In order to examine changes in biocompatibility with time, fresh specimens, along with specimens soaked in distilled water for 24 and 72 h were fabricated. Three other types of acrylic denture base resins were used to prepare the resin specimens. Biocompatibility (as measured by a metabolic assay, an agar overlay test, and a mutagenesis assay) of the composites was tested. The metabolic and mutagenesis assays were conducted with pure culture medium as a control. In this study, the reinforced acrylic-based hybrid denture composite resin with POSS showed improved biocompatibility and lower mutagenicity than the control. Statistical examinations showed the cell metabolic activity of the novel polymeric denture base resin in the 72-h immersion case as having almost the same inclination as the control. We hope that these results might aid in the development of a reinforced acrylic-based denture resin.
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ABSTRACT: Polylactide (PLA), a main biodegradable and biobased candidate for the replacement of petrochemical polymers, is stiff and brittle at room conditions. It is therefore of high interest to formulate new PLA-based materials suitable for applications demanding flexibility and toughness. In this work, novel blends of PLA with polyhedral oligomeric silsesquioxanes (POSS) grafted with longer (P1) and shorter (P2) arms of ethylene glycol derivatives were prepared and studied. It was hypothesized that, owing to their architecture with the central POSS cage grafted with arms, miscibility and stability of the blends could be improved. Indeed, PLA/P1 blends were homogeneous despite P1 relatively high M w of 9,500 g mol(-1). The blend with 20 wt% of P1, having T g at 16 °C, was transparent and flexible, elastomer-like material with excellent drawability. The blend remained homogeneous and retained its good drawability as well as flexibility during 6 months of aging at room temperature: a 2 % secant modulus of elasticity well below 100 MPa, a low yield stress below 2 MPa, and and a large strain at break of 8 (800 %). Contary to that, PLA/P2 blends were only partially miscible. Nevertheless, owing to the liquid state of the dispersed phase, the blend with 15 wt% of P2 was transparent and ductile, with T g at 49 °C, a relatively high yield strength of 29 MPa, and a large strain at break of 2.3 (230 %). The toughening mechanism involved the initiation of crazes and facilitation of their propagation by the liquid inclusions via the local plasticization effect.Colloid and Polymer Science 01/2014; 293(1):23-33. DOI:10.1007/s00396-014-3344-3 · 2.41 Impact Factor
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ABSTRACT: This article reports on the synthesis of a novel amphiphilic polyhedral oligomeric silsesquioxane (POSS) end-capped poly(2-(2-methoxyethoxy)ethyl methacrylate)-co-oligo(ethylene glycol) methacrylate) (POSS-P(MEO2MA-co-OEGMA)). These thermoresponsive organic–inorganic hybrid polymers exhibit critical phase transition temperature in water, which can be finely tuned by changing the feed ratio of OEGMA and MEO2MA. The lower critical solution temperature (LCST) of POSS-P(MEO2MA-co-OEGMA) increases from 31 to 59 °C with the increasing of OEGMA content. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) studies show that these polymers can self-assemble into spherical micelles with the thermosensitive block into the corona and the POSS forming the core, and larger aggregates are formed when the temperature values are above their LCSTs. These thermoresponsive polymers POSS-P(MEO2MA-co-OEGMA) with self-assembly behavior and tunable tempetature-responsive property have the potential applications in material science and biotechnology.Colloid and Polymer Science 11/2014; 292(11). DOI:10.1007/s00396-014-3262-4 · 2.41 Impact Factor
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ABSTRACT: Polysilsesquioxane-polyacrylate/silica hybrid latexes (PSQ-PAS) with high silicon content were prepared by directly mixing colloidal silica with polysilsesquioxane-polyacrylate emulsion (PSQ-PA), which was prepared through seeded emulsion polymerization using polymethacryloxypropylsilsesquioxanes as the core and polyacrylate (PA) as the shell respectively. The chemically bonded PSQ-PAS thin films were obtained via sol-gel process after addition of hydrophilic cosolvent to PSQ-PAS emulsion and subsequent drying at room temperature. The effects of silica/PSQ-PA ratio (w/w) on the film properties of hardness, optical property and thermal stability were investigated. Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS) and transmission electron microscopy (TEM) were used to characterize the chemical composition and morphology of the resultant hybrid particles. DLS and TEM results indicated that both PSQ and PSQ-PA particles had narrow size distribution and their average diameters were about 200 and 350 nm, respectively. Pendulum durometer, UV–vis spectroscopy, and thermogravimetric analysis (TGA) were used to characterize the hardness, optical property and thermal stability of PSQ-PAS latex films. The results showed that the PSQ-PAS films hardness increased with the increasing ratio of silica/PSQ-PA, whereas the transmittance decreased slightly. TGA curves demonstrated PSQ-PAS films displayed excellent thermal stability, and the residual silicon weight exceeded 30%. POLYM. COMPOS., 2014. © 2014 Society of Plastics EngineersPolymer Composites 02/2014; 36(2). DOI:10.1002/pc.22954 · 1.46 Impact Factor