Kinetic evaluation of hyperbranched A2+B3 polycondensation reactions

The kinetics of hyperbranched A(2) + B-3 systems is discussed theoretically with respect to the development of the 7 different structural units, the degree of branching, DB, and the monomer sequences considering the adjacent groups of a structural unit. For A(2) + B-3 systems, the comonomer ratio, the relative rate constants and the process conditions have an influence on the resulting structure as shown by numerical simulations. With increasing A:B ratios f(A/B), the degree of branching will be increased. Also the relative reaction rate constants have a strong impact on the distribution of structural units, especially when the reaction rate constants for the pathway of the B-3 monomer are changed. On the other hand, differences in the reaction rate constants for the pathway of the A(2) monomer do not have any influence on the degree of branching. The simulation indicates that slow addition of either both monomers or just the B-3 monomer has the strongest effect on the resulting DB. In all cases, the conversion is a critical issue to obtain high molecular weight products.