Characterization of Aquazol polymers using techniques based on pyrolysis and mass spectrometry

• Aquazol 500 is a polyoxazoline recently used as consolidant in restoration.
• We characterized Aquazol 500 by techniques based on pyrolysis and mass spectrometry.
• We used Py-GC/MS and DEMS (direct exposure mass spectrometry).
• The thermal degradation occurs by random chain scissions of the polymer backbone.
• The analytical approach permits the identification of Aquazol 500 in treated heritage objects.

Aquazol is the commercial name of a family of thermoplastic polymers made up of poly(2-ethyl-2-oxazoline) (PEOX), which has only been investigated to a limited extent. PEOX is a nonionic tertiary amide formed by cationic ring opening polymerization. The most interesting properties of Aquazol include non-toxicity, solubility in a range of organic solvents, such as alcohols and ketones, and hydrophilicity. Due to the combination of these proprieties, Aquazol has been introduced as an adhesive and coating in the conservation of paintings, wood and textiles. Pyrolysis coupled with mass spectrometry (Py-GC/MS and DEMS) and thermal analysis techniques (TGAs) were used in this study to investigate the chemical composition of Aquazol 500, in order to provide the molecular characterization of the polymer and to identify it in complex matrices. A sample taken from a paint layer consolidated with Aquazol 500 was also analysed, to evaluate the ability of the proposed methods to identify oxazoline polymers in complex matrices.