CONDENSATION POLYMERIZATION OF PYROGALLOL AND BENZALDEHYDE

Novolac-type polycondensation of benzaldehyde (B) and pyrogallol (P) h as been carried out at 60 degrees C, 75 degrees C and 90 degrees C and at B/P mole ratios of 1.5 and 3.0 using phosphoric acid as catalyst. The reaction follows a 2nd order rate law. By using GC consumption dat a of benzaldehyde and pyrogallol, kinetic parameters such as the overa ll rate constants, activation energies (E(a)) and logA values are inve stigated. The activation energies for 1.5 and 3.0 B/P mole ratios are found as 62.3 kJ mol(-1) and 56.4 kJ mol(-1), respectively. The molecu lar weights of the resins determined by measuring intrinsic viscositie s (25 degrees C, THF) are in the range of 0.03 to 0.07 dL g(-1) at var ious temperatures and B/P mole ratios.