The structural units and degree of branching of the hyperbranched polymers formed from general self-condensing vinyl polymerization (SCVP) with non-equal reactivities were investigated by the mechanism of kinetics. The dependent relationships of the average degree of branching ( ) on the conversion of group A (x), reactivity ratio of A* to B* (r), and activator/monomer ratio (α) were calculated, respectively. For any specified r and α, increases monotonously with increasing x. For a specified x, decreases monotonously with increasing r under the condition of α＜x/(1＋ ) and has a maximum under the condition of α＞x/(1＋ ). However, the maximum degree of branching does not exceed 0.5 for the SCVP. If some suitable monomers were added into the reaction system at the end of SCVP and all active groups were consumed, a higher value of , 2α/(1＋α), could be obtained.

Key words: hyperbranched polymer, self-condensing vinyl polymerization (SCVP), degree of branching, kinetics