The polymerisation kinetics of lower dialkyl itaconates

Abstract

The free radical polymerisation kinetics of diethyl- (DEI), dipropyl- (DnPI), dibutyl- (DnBI), and dihexyl itaconate (DHI) in the bulk were studied in the temperature range from 50 to 70 degrees C. The concentration of the initiator, 2,2'-azoisobutyronitrile (AIBN), was varied between 0.02 and 0.085 mol/dm(3). The rate of polymerisation (R-p), degree of polymerisation (DP), overall polymerization rate constant (K), the ratio of the propagation and termination rate constants (k(p)/k(t)(1/2)), as well as the chain transfer constant to monomer (C-M) were determined. The values of R-p, K, and k(p)/k(t)(1/2) of the investigated monomers all increase with increasing size of the alkyl group in the ester substituent, whereas C-M decreases when going from the dimethyl to the dihexyl ester. The values of C-M are larger than the corresponding values for the alkyl esters of methacrylic acid.