Thermal degradation behaviors of polyoxymethylene in nitrogen are systematically studied by Thermo-gravimetry-Fourier Transform infrared spectroscopy (TG-FTIR). Two primary degradation mechanisms are definitely determined by the production of formaldehyde and carbon monoxide collected from successive FTIR spectrum. First, POM tends to split off formaldehyde starting at unstable chain-ends, then random chain scission occurs at elevated temperature, and several related reactions possibly occur during the degradation process. The results prove that during the degradation, formaldehyde is the predominant product, and therefore polyether as die stabilizers used can greatly improve the degradation temperature of POM in the initial stage, and consequently effectively inhibit the thermal degradation of POM. (c) 2006 Wiley Periodicals, Inc.