Polymer, Vol.125, 117-125, 2017
Dynamics of hyperbranched polymers derived from acrylated epoxidized soybean oil
In this article we demonstrate the role of chain architecture on the relaxation dynamics of poly(acrylated epoxidized soybean oil) (PAESO), a hyperbranched polymer, with a particular focus on the role played by intramolecular loops. PAESO is produced by reversible addition-fragmentation chain transfer (RAFT) polymerization from acrylated epoxidized soybean oil (AESO) containing an average of 2.6 polymerizable acrylic moieties per trigylceride. By adjusting the relative concentrations of solvent, monomer, and RAFT chain transfer agent, PAESO undergoes a series of both inter-molecular and intra-molecular reactions such that both molecular weight and chain architecture vary throughout the reaction. While intermolecular reactions are responsible for branching, intramolecular reactions introduce loops to the structure with altogether different consequences on chain conformations and segmental dynamics. Using dynamic shear rheology in the linear viscoelastic regime we find that Rouse/Zimm-like dynamics persist to molecular weights as high as 390 kDa and that the primary influence of looping is to strongly suppress the number of Zimm relaxation modes. (C) 2017 Elsevier Ltd. All rights reserved.