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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 r2 (HEMA as M2) 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 r2 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 r1 as well as r2. Numerical values obtained for the system macromonomer 1 (M1)/HEMA (M2) amounted to r1 = 0,16 and r2 = 0,48; r1 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. |
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