No abstract

Hyperbranched polymers (HBPs) formed by a self-condensing vinyl polymerization (SCVP) of copolymerization of AB* monomers slowly added into trifunctional C 3* cores under various feed rates were investigated by a kinetic model. The dependences of average molecular weight, polydispersity, degree of branching, and number of structural units of the hyperbranched polymers on the feed rate were calculated by a generating function method. It was found that the final polydispersity index (PDI) can be attained below 1.5 by a slow addition of AB* at a feed rate parameter, φ, less than 2. While the AB* monomers fed quickly, the system with a lower content of the C 3* cores results in a broader molecular weight distribution. A high degree of branching, about 0.66, can be achieved by addition of AB* monomers into a small amount of C 3* cores at φ lower than 10.

Hyperbranched polymers generated from the polymerization of AB2-type monomers and trifunctional cores with various reactivities were examined by means of the kinetic theory. The average molecular weight, polydispersity, degree of branching, and structural units of the hyperbranched polymers, which all changed with time or conversion, were calculated by a generating function method. Growth of the hyperbranched polymers was limited by adding C3 monomers because no reactions occur among molecules with a core unit. The presence of multifunctional core monomers can reduce the polydispersity of the hyperbranched polymers but leads to less branching and more residual of unreacted core monomers. Increment of the reactivity of core monomers results in a lower weight-average degree of polymerization and a narrower molecular weight distribution of the hyperbranched polymers.