Bulk polymerization of diallyl benzene-dicarboxylates I. Influence of temperature on allyl group reactivity

The bulk polymerization of the three isomeric diallyl benzene-dicarboxylates was carried out in the temperature range 80–285°C. The progress of the polymerization process was examined by determination of the conversion of allyl groups double bonds. The reactivity of these groups in the polymerization increases in the following order of isomers: ortho < para < meta at 80–230°C. At temperatures above 200°C the thermal polymerization with activation energies for ortho, meta and para isomers 32, 27, and 28 kcal/mol of allyl group, respectively, has been observed. With the increase of temperature from 80 to 230°C for each of the monomers the number of allyl groups consumed when forming one C? C chain (degree of chain polymerization) decreases, but at the same time the kinetic chain length increases several times. The results have been explained by the growing role of chain transfer reactions with simultaneous increase of an ability to reinitiation by occured radicals. The mechanisms of thermal polymerization have been proposed.