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The analytical expressions of the various structural units and the average degree of branching for the hyperbranched polymers resulted from AB_2 polycondensation with substitution effect were derived by the kinetic mechanism.The reactivity difference between the B group in linear unit and that in terminal group has great effect on the molecular parameters of the products obtained.The concentration of terminal units has a maximum with the increase of the conversion of A groups(x).The higher the reactivity ratio(r) of linear B group to branched one is,the later the maximum appears and the larger it is.The degree of branching of the hyperbranched polymers obtained is controllable by adjusting the parameters of r and x,which increases with increasing both x and r.
The analytical expressions of the various structural units and the average degree of branching for the hyperbranched polymers resulted from AB 2 polycondensation with substitution effect were derived by the kinetic mechanism. The reactivity difference between the B group in linear unit and that in terminal group has great effect on the molecular parameters of the products obtained. the concentration of terminal units has a maximum with the increase of the conversion of A groups (x). higher higher reactivity ratio (r) of linear B group to branched one is, the later the maximum appears and the larger it is.The degree of branching of the hyperbranched polymers obtained is controllable by adjusting the parameters of r and x, which increases with increasing both x and r.