The temperature-dependent desorption behavior of surfactants in linear low-density polyethylene (LLDPE) blend films was studied with Fourier transform infrared spectroscopy at 25, 40, and 50 degreesC. The LLDPE/low-density polyethylene blend was 70/30. Three different specimens (labeled II, III, and TV) were prepared with various compositions of the surfactant, sorbitan palmitate (SPAN-40), and the migration controller, poly(ethylene acrylic acid) (EAA). The calculated diffusion coefficients of SPAN-40 in specimens II, III, and IV at 25, 40, and 50 degreesC varied from 9.6 x 10(-12) to 17.4 x 10(-12) cm(2)/s, from 5.5 x 10(-12) to 11.0 x 10(-12) cm(2)/s, and from 3.1 x 10(-12) to 5.8 x 10(-12) cm(2)/s, respectively. In addition, the activation energies of specimens II, III, and IV measured between 25 and 50 degreesC were 18.74, 19.42, and 20.14, respectively. Hence, the desorption rate of the surfactant increased with the temperature and decreased with an addition of EAA, but the activation energy increased with EAA. The diffusion kinetics, analyzed with a plot of the integrated intensity ratio as a function of time, log(I-t/I-infinity) versus log t, at 25, 40, and 50 degreesC obeyed Fickian diffusion behavior. (C) 2000 John Wiley & Sons, Inc.