writer：Heng Chen, Jie Kong*
keywords：Highly Branched Polymers
source：期刊
specific source：J. Phys. Chem. B, 2014, 118 (12): 3441-3450
Issue time：2014年
Terminal index (TI) was presented as a new characteristic parameter for quantitative description of branched and cyclic topology of highly branched soluble polymers derived from A2 + B3 stepwise polymerization. TI is defined as the ratio of terminal units of an A2 + B3 type highly branched polymer to those in its perfect hyperbranched counterpart. TI is concisely represented as T/(D + L), which can be conveniently calculated from a quantitative NMR spectrum. The model of soluble A2 + B3 type polymers is suggested as an intermediate between multicyclic polymers and
perfect hyperbranched polymers. The TI ranges between 0 and 1 where a higher TI indicates a perfect hyperbranched topology while a low TI indicates a multicyclic structure. The analysis of soluble A2 + B3 type polyesters and polycarbosilanes as model
polymers demonstrates that TI as a more precise parameter, along with degree of branching, can be generally applied to understand the fine topology of highly branched polymers derived from A2 + B3 polymerization.