Analysis of volatile organic compounds in polyurethane coatings based on Eucalyptus sp bio-oil pitch using comprehensive two-dimensional gas chromatography (GC x GC)

The development of biomass products seems to be a near-term alternative to fossil derivatives, which aim to mitigate climate changes. It is therefore necessary to investigate whether biomass technologies are really safe and without environmental impact. This work presents a characterization of the volatiles that are released from biopitch and its polyurethane films. Biopitch was obtained via the distillation of Eucalyptus sp. bio-oil; it was recovered by the condensed smoke that was obtained during slow pyrolylis, which is a process that is used to produce charcoal for the iron-making industry in Brazil. Biopitch and castor oil mixtures, in different proportions, were used as polyols in the polyurethane synthesis. The reactions were carried out when the polyol mixtures were stirred together with polymeric MDI (4,4' methylene diphenyl diisocyanate) NCO/OH = 1.1 and dibutyltin dilaurate as a catalyst. The films were analyzed by comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry (GC × GC/TOFMS). The best experimental conditions that permit the identification of 104 volatile organic compounds were determined. Although the analysis was not quantitative, it was possible to conclude that a large content of biopitch led to the release of a large number of different substances. The main compounds that were released are phenolic methoxyl substituted substances with one aromatic ring and a low toxicity. Due to its high resolution and sensitivity, the methodology that was used seems to be adequate for the analysis of other macromolecular fractions (biopitches) and polymeric materials that are derived from bio-oils.