CIOP   05384
CENTRO DE INVESTIGACIONES OPTICAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Measurement of thermal expansion post-curing Bis-GMA resins with a fiber optic interferometric sensor
Autor/es:
GUSTAVO ARENAS; RICARDO DUCHOWICZ
Lugar:
La Plata
Reunión:
Conferencia; Humboldt Kolleg - International Conference on Physics; 2011
Institución organizadora:
UNLP-Humbold
Resumen:
In this work we present a simple technique to measure thermal contraction of small samples of Bis-GMA photocuring resin using a Fizeau fiber optic interferometer and a thermocouple previously embedded in the specimen before photo-polymerized. After introducing the sample in a thermostatic bath operating in heating/cooling cycles,  measurement are performed by recording the contraction of the heated sample, in its cooling cycle, using a fiber optic Fizeau interferometer to determine the length changes simultaneously with the temperature evolution obtained with the thermocouple. Contrasting these two values, it is possible to determine the coefficient of thermal expansion (CTE) in a simple form. Moreover, not only possible to obtain the average CTE, but its value as a function of temperature can be determined, which is potentially useful to characterize many physical situations of interest in industry and research. For the specific case under study, coefficients of the monomer and vitrified resins were obtained.  Solid samples of the Bis-GMA resin thermal expansion coefficient values range from 120 x 10-6 1/K and 290 x 10-6 1/K. These results are in agreement with classical methods, offering a simpler and more compact experimental scheme. Measurement of contraction is optically stable, intrinsically self-calibrating and noninvasive. Since it provides information in time, it may be suitable to study shrinkage profiles and kinetic of polymerization. Furthermore it can be applied to other materials such as glass, rubber, metals, etc.