On-line version ISSN 1678-5169
POLEY, Luiz H. et al. Photothermal characterization of low density polyethylene food packages. Polímeros [online]. 2004, vol.14, n.1, pp. 8-12. ISSN 1678-5169. http://dx.doi.org/10.1590/S0104-14282004000100007.
The present work discuss the applicability of photothermal techniques for determining diffusion coefficients of oxygen and carbon dioxide of commercial low-density polyethylene (LDPE). The methodology involves the monitoring of diffused gas by a photoacoustic analyzer. Diffusion coefficients measured for CO2 and O2 were 2.77 x 10-8 cm2/s and 1.68 x 10-7 cm2/s, respectively. To support the gas diffusion results, thermal properties were studied using photoacoustic spectroscopy and crystallinity was determined using X-ray diffraction. Values obtained for thermal diffusivity and specific heat capacity were 1.65 x 10-3cm2/s and 2.33 J.cm-3K-1, which are in good agreement with values available in the literature for pure LDPE and thus assure reliability of diffusion coefficients values.
Keywords : Photoacoustic spectroscopy; LDPE; diffusion coefficients.