Prediction of intrinsic viscosities of dendritic, hyperbranched and branched polymers

摘要

The intrinsic viscosities of a series of dendritic, hyperbranched, branched and linear polymers were predicted using a bead model. The model is an extension of the Muthukumar model allowing for a large range of degrees of branching. Intrinsic visosities were calculated from the radius of gyration and by using the hydrodynamic tensor approach. It is found that (flexible) hyperbranched polymers exhibit a maximum of intrinsic viscosity as function of molecular weight, as dendrimers do, but the maximum is situated at a higher level of intrinsic viscosity and shifted to higher molecular weights. Terminating the end groups with long-chain aliphatic tails decreases the intrinsic viscosity once as a certain threshold molecular weight is exceeded. The value of the latter increases with increasing degree of branching.