Analysis of Lacquer and CNSL Using Infrared Spectrometer and Pyrolysis-GC/MS

Nowadays, synthetic resin varnish such as cashew nut shell liquid (CNSL) is being used as well as traditional lacquer. The code of ethics states that material must be identical to the original when preserving cultural heritage. Therefore, lacquer should be used. However, problem is that even experts have difficulties differentiating lacquer and CNSL as they have similar components. Therefore, this study was carried out to identify the difference between lacquer and CNSL using IR and Py-GC/MS. As a result of IR, in lacquer, 720 cm-1 peak was detected and in CNSL, 750 cm-1, 720 cm-1 and 700 cm-1 peaks were detected. The results of Py-GC/MS detect benzene compounds and alkyl chains for both varnishes. However, hexanoic acid was detected from CNSL but not lacquer. Using these analytical methods, the differences between lacquer and CNSL can be identified on the scene. This is expected to be applied to the authentic conservation and restoration of lacquerware.