Thermal degradation of polyester coating powders: 1,4-dicyanobenzene as an occupational marker compound

Abstract

A method for the determination of emissions in workroom air as a result of the thermal degradation of polyester coating powders is described. The method is based on the determination of certain marker compounds only. Polyester coating powders were degraded thermally in laboratory experiments and 1,4-dicyanobenzene was chosen as the marker compound. An air sampling method and a high-performance liquid chromatographic method for the determination of the marker compound are proposed. The detection limit for a 48-I air sample was 0.4 microgram m-3.

Determination, Correlation, and Thermodynamic Analysis of the Solid–Liquid Phase Equilibrium of 1,4-Dicyanobenzene in Pure Solvents at Various Temperatures

“…Combined with the PXRD analysis, a conclusion can be drawn that no solvate formation or polymorph transformation existed during the solubility measurement experiments. Based on the DSC analysis, the melting temperature ( T m ) of DCB was 499.01 K with a standard uncertainty of 0.3 K. The value of T m determined in this work is in good agreement with that reported by Pukkila and Kokotti . The slight deviation may result from the differences in instruments, measurement methods, sample sources, experimental environments, and other related factors.…”

“…Based on the DSC analysis, the melting temperature (T m ) of DCB was 499.01 K with a standard uncertainty of 0.3 K. The value of T m determined in this work is in good agreement with that reported by Pukkila and Kokotti. 39 The slight deviation may result from the differences in instruments, measurement methods, sample sources, experimental environments, and other related factors. The enthalpy of fusion was estimated to be 22.94 kJ/mol with a relative standard uncertainty u r (Δ fus H) of 0.03.…”

Health hazard evaluation report: HETA-90-174-2231, Modern Materials Incorporated, Rochester, Indiana.

“…Although the specific organics varied with the choice of powder, xylenes and isobutyl-methyl ketone were the most abundant compounds that were released by heating epoxies. A similar set of studies published by Pukkila et al indicates that benzil can be used as an indicator of vapors released during the normal curing process of polyester paints, and that the presence of 1,4-dicyanobenzene is an indicator of their thermal decomposition (Pukkila 1989). Thermal decomposition was reported to begin at temperatures of about 350 o C (650 o F).…”