STUDY OF MELTING PROCESSES IN FATTY-ACIDS AND OILS MIXTURES - A COMPARISON OF PHOTOPYROELECTRIC (PPE) AND DIFFERENTIAL SCANNING CALORIMETRY(DSC)

Parallel photopyroelectric (PPE) and differential scanning calorimetry (DSC) measurements on some saturated and unsaturated fatty acids were performed in a temperature range, including their melting point. The melting temperature and the critical behavior of all static (volume sp ecific heat) and dynamic (thermal diffusivity, conductivity and effusi vity) thermal parameters were obtained for pelargonic (C9:0), behemic (C22:0) and oleic (C18:1) fatty acids. A similar PPE-DSC comparison st udy was performed for a triglyceride mixture (10% fully hydrogenated p alm oil in sunflower oil), material involved in various phase transiti ons in the range -60 degrees C to +60 degrees C, II was demonstrated t hat the two techniques are in a way complementary: PPE gives the behav iour of the thermal parameters in the melting region, and DSC the sign and amount of latent heat involved in the process; both methods suppl y information about the melting temperature.