Reactivity of a polyamine macromonomer in radical copolymerization with 2‐hydroxyethyl methacrylate

A series of copolymerization reactions of polyamine macromonomer 1 having controlled molecular weight with 2‐hydroxyethyl methacrylate (HEMA) were examined, in order to obtain a reliable estimation of the reactivity of the macromonomer in radical copolymerization. The monomer reactivity ratio r 2 (HEMA as M 2 ) was estimated to be 0,49 by a newly developed method which is expressed by Eqs. (4) and (5). This method, however, could basically be applied only to the estimation of the r 2 value. On the other hand, a novel method for the evaluation of the copolymer composition from the conversion of each monomer using gas chromatography and ultraviolet fourth‐order derivative spectra enabled us to estimate r 1 as well as r 2 . Numerical values obtained for the system macromonomer 1 (M 1 )/HEMA (M 2 ) amounted to r 1 = 0,16 and r 2 = 0,48; r 1 is much smaller than the reactivity ratio of a low‐molecular‐weight analogue of 1 , a fact which indicates that the reactivity of the growing radical with a 1 terminal toward 1 should be remarkably smaller than in case of a low‐molecular‐weight analogue of 1 . This may be explained by the presence of the kinetic excluded volume effect.