RHEOLOGICAL CHARACTERIZATION OF POLYMER BLENDS FOR MANUFACTURING OF DENTAL PROSTHESES
Daniel Osorio1; Andrey Perez1; Sandra Gaviria2; Diana Lopez1
1 Universidad Nacional De Colombia; 2 New Stetic
doi:10.20906/CPS/COB-2015-2707
Resumo
In this study the rheological response of a polymer blend composed by polymethyl methacrylate- (PMMA) and monomer (MMA) used for manufacturing dental prosthesis was analyzed. Preliminary test were performed using the technique of concentric cylinders in a conventional viscometer with the objective to determine the effect of shear stress on the viscosity. After that, two types of oscillatory tests were performed using rotational rheometer with cooling / heating ETC System, fed by liquid nitrogen for temperature control. The first kind of oscillatory test (one stage) was carried out at 25ºC and -6ºC, trying to simulate the behavior of the blend under the mixing and storage stage. The second kind of oscillatory test (multistage) was developed following a sequence of temperatures: 20ºC,-10ºC,-4 ºC and 25ºC, trying to simulate the thermal path during the manufacture of the prostheses. It was found that changes in the viscosity and shear stress are functions of time of polymerization, and that the storage G'(ω) and loss modulus, G''(ω), can be good properties to characterize the different polymerization stages that passes the polymer blend during a production process of dental prostheses.
Palavras-chave: Rheology; PMMA; polymer blends; dental prostheses