Model-Based Visualization and Understanding of Monomer Sequence Formation in Gradient Copoly(2-oxazoline)s On the basis of 2-Methyl-2-oxazoline and 2-Phenyl-2-oxazoline

• DOI: 10.1021/acs.macromol.5b01642
• Publication Date: 2015-10-23T14:01:13Z
• Authors: Paul H. M. Van St...; Bart Verbraeken; Marie-Françoise R...; Richard Hoogenboom; Dagmar R. D’hooge
• Keywords: 02 engineering and technology; 0210 nano-technology

For the first time, the formation of monomer sequences of individual macromolecules during cationic ring-opening copolymerization (CROcoP) of 2-methyl-2-oxazoline (MeOx) and 2-phenyl-2-oxazoline (PhOx) in acetonitrile (3 mol L–1; 100–140 °C; target degree of polymerization (DP): 50–400) is visualized via kinetic Monte Carlo simulations with model parameters optimized based on experimental data. It is shown that chain transfer via β-elimination and branching reactions are required to describe the experimental data. At complete monomer conversion for target DPs below 200, at most 5% of the chains are macromonomers and the average number of branches per chain remains below 15%. A higher amount of chains with a defined, steeper MeOx to PhOx gradient is obtained by lowering the polymerization temperature albeit at the expense of polymerization time. The simulations results highlight the great potential of CROcoP of 2-oxazolines for the direct synthesis of well-defined steep gradient copolymers.