Thermogravimetric analysis of ethylene-vinyl acetate copolymers with Fourier transform infrared analysis of the pyrolysis products

Ethylene-vinyl acetate (EVAc) copolymers were examined using thermogravimetric analysis (TGA). The method permitted rapid and reproducible determination of the vinyl acetate content of the copolymer. The weight loss profile for low density polyethylene, i.e., ethylene-vinyl acetate with a 0% vinyl acetate content, showed a single-step decomposition from 460 to 560°C that accounts for 100% of the observed weight loss of the sample. The heating of ethylene-vinyl acetate with vinyl acetate contents from 9 to 40% resulted in a two-step decomposition in the ranges 360–450°C and 450–550°C. A TGA-Fourier transform infrared spectrometer (FTIR) coupled system permitted the identification of the pyrolytic products in the effluent gas as acetic acid for the first-step product, and a mixture of 1-butene, carbon dioxide, ethylene, methane, and carbon monoxide.