Differentiation between copal and amber by their structure and thermal behaviour

Abstract The relationships between the polymerization related to structure and composition of different types natural resins were determined. Analyses carried out by Fourier transform infrared spectroscopy (FTIR), differential thermal analysis–thermogravimetry (DTA-TG) hot stage microscopy (HSM). Copal specimens collected from Mai-Ndombe Lake, Democratic Republic Congo, amber pieces that came Bitterfeld, Germany, Kaliningrad, Russia. FTIR spectra copal show a vibrational band at 1643 cm −1 (C=O stretching) attributed communic acids, while shows 1735 associated with ester-group vibrations shoulder about 3340 , suggesting partial oxidization. DTA main exothermic peak, combustion, 546–552 °C in 518 copal. derivative thermogravimetry (DTG) peaks vary resin types; amber, they occur 333–335, 401–404 548–555 are mass losses 31, 26 39 mass%, respectively; 394 507 °C, 71 27 respectively. In copal, (HSM) start sintering 131 followed an expansion produced material decomposition generation gases cannot be released because plastic behaviour. Finally, increase pressure produces explosion results lower viscosity liquid, which this point can no longer support internal gases. samples, smaller decrease is observed occurs 150 significant change their morphology.