Abstract
A dried linseed film was analyzed by two-stage pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) to investigate its structure and pyrolysis mechanisms. Heating furnace temperatures appropriate to the pyrolysis were determined to be 300°C and 600°C by thermogravimetry/differential thermal analysis-mass spectrometry (TG/DTA-MS). The dried linseed film was then pyrolyzed at 300°C and 600°C. From the pyrolysis at 300°C, saturated and monoenyl fatty acids were detected, and the relative peak intensities of hexadecanoic acid and of octadecanoic acid were highest. These fatty acids are the pyrolysis products of the terminal groups. The dried linseed film is terminated with saturated and monoenyl fatty acid esters, especially with hexadecanoic acid ester and octadecanoic acid ester. From the pyrolysis at 600°C, alkenes, alkanes and fatty acids were detected. Some alkenes and alkanes have carbon chains longer than the side chains of the glycerides. The alkenes and alkanes are the pyrolysis products of the glyceride polymers generated by the autoxidative C-C cross-linking. The formation of fatty acids is also attributed to the cross-links of the glyceride polymers. These results reveal that autoxidative cross-linking proceeds through the polymerization of linseed oil.
