Artículos de revistas
Evaluation of the Mooney viscosity of natural rubber by near-infrared spectroscopy
Registro en:
Spectroscopy Letters. Taylor & Francis Inc, v. 38, n. 6, n. 741, n. 748, 2005.
0038-7010
WOS:000234818600006
10.1080/00387010500316064
Autor
Pasquini, C
Figueiredo, FC
Prince, B
Institución
Resumen
The direct near-infrared spectroscopic reflectance measurements of prevulcanized natural rubber (brown crepe) was employed for determination of its Mooney viscosity. NIR reflectance spectra were obtained for a total of 100 samples whose Mooney viscosity (VM in the range 68-95 units) have been determined by the standard reference procedure using a commercial computerized Mooney viscometer. These samples were employed as the raw material or were treated to achieve better homogenization. A Fourier transform near infrared (FT-NIR) spectrophotometer was employed, and the reflectance spectra were obtained with resolution of 4 cm(-1) in the range 4000-10,000 cm(-1) as an average of 75 scans. The samples were split in a calibration set containing 70 samples and in an external validation set consisting of the remaining 30 samples. The calibration and validation spectra sets were treated to correct for baseline shift, further transformed by first derivative and finally modeled by partial least squares (PLS) employing four latent variables. The model was evaluated with the external sample test set, and a RMSEP of 3.6 and 3.9 units of Mooney viscosity were obtained for homogenized and nonhomogenized samples, respectively. The NIR method is capable of determining the Mooney viscosity in few minutes in the non-pretreated sample with an error that is satisfactory for quality control of natural rubber destined for automobile tire manufacturing. 38 6 741 748