STUDYING OF PROPERTIES OF THE EXTRACTS OF THE PINE RECEIVED BY SOLVENTS OF VARIOUS NATURE BY METHOD OF THE DIFFERENTIAL SCANNING CALORIMETRY (DSC)
The paper studies the influence of solvents on the properties of pine bark extracts. Thermal stability of the extractives obtained is assessed by differential scanning calorimetry (DSC). It is found that destruction of the extractives consists of several stages occurring in the respective temperature ranges and is accompanied by a change in the energy balance system. Destruction of aqueous pine extract substances has an endothermic and 2 exothermic effects and an ethanolic pine extract has an endothermic and 3 exothermic effects. The DSC of the alkaline extract has an endothermic and 5 exothermic effects. Destruction of an alkaline extract, unlike aqueous and ethanolic extracts, comes up with weight loss in four stages, which is likely due to a higher degree of crystallinity of the extractives. The experimental results showed that the extractives could be used as tanning agents in leather and fur production and highlighted their properties stability during storage under unfavorable conditions.