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Migration and release profile of Chimassorb 944 from low-density polyethylene film (LDPE) in simulated landfills

1999; Elsevier BV; Volume: 64; Issue: 2 Linguagem: Inglês

10.1016/s0141-3910(98)00210-9

1873-2321

Nadejzda Haider, Sigbritt Karlsson,

Recycling and Waste Management Techniques

A low-density polyethylene film (LDPE) with a commercial polymeric hindered piperidine stabiliser was exposed to simulated landfill environments, viz. aqueous media at pH 5 and 7, temperatures of 25, 50, 80 and 105°C and solid-to-liquid ratios of 1:10 and 1:5. The migration of the stabiliser, including diffusion and desorption, and the resultant degradation of the polymeric matrix were studied. For this purpose, an ultrasonic extraction technique using chloroform as extraction solvent was explored to recover the non-migrated stabiliser from the polymeric matrix, followed by quantitative analysis of the extracted stabiliser by UV spectroscopy. It was found that the release of Chimassorb 944 from the degrading matrix increases at higher temperature, longer time, lower pH and higher solid-to-liquid ratio. In general, the kinetics of this total migration process are well described by equations of the first order and an Arrhenius-type relationship applicable for the temperature-dependence of the constants. General constants calculated for the total migration process allowed the complete release of the stabiliser at different conditions in landfill to be predicted. Surface morphology of the LDPE film before and after treatment was studied by scanning electron microscopy (SEM). Degradation of the polymeric matrix was shown by Fourier transform infrared spectroscopy (FTIR) and size-exclusion chromatography (SEC).