J. Phys. IV France
Volume 125, June 2005
Page(s) 573 - 576

J. Phys. IV France 125 (2005) 573-576

DOI: 10.1051/jp4:2005125132

Optimization of dying variables in PET: Using thermal diffusivity response as a probe in a multivariable algorithm

L. Olenka1, A.F. Rubira2, E.C. Muniz2, A.N. Medina1, M.L. Baesso1 and A.C. Bento1

1  Departamento de Física, Universidade Estadual de Maringá, Av. Colombo 5790, Maringá-Paraná, 87020-900, Brazil
2  Departamento de Química, Universidade Estadual de Maringá, Av. Colombo 5790, Brazil

The conventional process (CP) using aqueous dyeing and the supercritical CO2 (SC-CO2) impregnation were used in the present work to impregnate Polyethylene terephthalate (PET) under several conditions by varying Time, CO2-Pressure, Temperature, Treatment and using fixed dye concentration (2 wt%) and dye color (Blue Samaron).. Samples were prepared following a Factorial Planning Design (FP) of the experiments and the thermal diffusivity ($\alpha$) were the FP response. It was found $\alpha$ in the range 1.0 to $2.0 \times 10^{-3}$ cm2/s, for CP and, from 1.4 to $1.8 \times 10^{-3}$ cm2/s for the SC-CO2 process. The thermal diffusivity increases if compared to virgin PET but, in order to analyze the thermophysical data, we shall analyze the variable effects implicit in the sample using the mains and the multivariable algorithm (MVA). Results contrast with a former photoacoustic work where intensities were used instead and showed that SC-CO2 process is more effective in incorporating dyes than the aqueous impregnation.

© EDP Sciences 2005