Kinetic Evaluation of Hyperbranched A₂ + B₃ Polycondensation Reactions

Abstract

Abstract 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. Degree of branching ( DB ) versus conversion of A‐functionalities ( p A ) for various monomer compositions. image Degree of branching ( DB ) versus conversion of A‐functionalities ( p A ) for various monomer compositions.