Studies of thermal polymerization of vegetable oils with a differential scanning calorimeter

Vegetable oils are often thermally polymerized to provide a vehicle for pri nting inks and paints. The formations of isomerization, and the intra- and intermolecular bonds involved in the thermal process are crucial in designi ng a product with the appropriate characteristics. it was found, with a dif ferential scanning calorimeter, that the thermal polymerization of various vegetable oils could be activated at lower temperatures under a dry-air pur ge and/or in the presence of metallic catalysts. The Diels-Alder reaction a nd the formation of intermolecular bonds in alkali-refined soybean oil unde r a dry-air purge could be activated at 99 and 161 degrees C in the presenc e of metallic catalysts, compared with 231 and over 300 degrees C in the ab sence of metallic catalysts, respectively. The energies needed to activate the Diels-Alder reaction and to form intermolecular bonds were calculated, and is in good agreement with available data. The hardness test of baked ve getable-oil systems was also implemented to qualitatively determine the deg ree of cross-linking.