FT-IR studies of factors affecting the diffusivity of oligo (oxyethylene) fatty acid ester in PE films: Effect of temperature, ethylene oxide chain length and base resin type

A migration kinetics study of a series of oligo (oxyethylene) fatty acid esters of various chain lengths in polyethylene film was studied using Fourier transform infrared (FT-IR) spectroscopy. Diffusion coefficients (D) were determined as a function of temperature, ethylene oxide (EO) chain length and base resin type. The activation energy of diffusion (Ea) for each oligo (oxyethylene) fatty acid ester was determined using the Arrhenius plot of D dependence on inverse temperature. The correlation between obtained D and the number-averaged molecular weight Mn of oligo (oxyethylene) fatty acid ester was described well by a power law expression (D=bMn−a), and the parameters a and b were determined from experimental data. Two other models, which have the form of an Eyring expression, were derived to express the effects of temperature and EO chain length on the diffusion process of oligo (oxyethylene) fatty acid esters. Diffusivity of oligo (oxyethylene) fatty acid ester in linear low density polyethylene (LLDPE) was higher than in high density polyethylene (HDPE) and low density polyethylene (LDPE). [Display omitted] •Effects of temperature, EO chain length and resin type on diffusivity are studied.•The molar mass dependence of diffusivity is described by a power law (D=bMn−a).•Two Eyring-type models involved in effects of temperature and EO number are given.