• Van Steenberge, Paul
• Reyniers, Marie-Françoise
• Marin, Guy
• Dhooge, Dagmar R.

Abstract

Based on kinetic Monte Carlo simulations of the monomer sequences of a representative number of copolymer chains (approximate to 150,000), optimal synthesis procedures for linear gradient copolymers are proposed, using bulk Initiators for Continuous Activator Regeneration Atom Transfer Radical Polymerization (ICAR ATRP). Methyl methacrylate and n-butyl acrylate are considered as comonomers with CuBr2/PMDETA (N,N,N',N '',N ''-pentamethyldiethylenetriamine) as deactivator at 80 degrees C. The linear gradient quality is determined in silico using the recently introduced gradient deviation (< GD >) polymer property. Careful selection or fed-batch addition of the conventional radical initiator I-2 allows a reduction of the polymerization time with ca. a factor 2 compared to the corresponding batch case, while preserving control over polymer properties (< GD > approximate to 0.30; dispersity approximate to 1.1). Fed-batch addition of not only I-2, but also comonomer and deactivator (50 ppm) under starved conditions yields a < GD > below 0.25 and, hence, an excellent linear gradient quality for the dormant polymer molecules, albeit at the expense of an increase of the overall polymerization time. The excellent control is confirmed by the visualization of the monomer sequences of ca. 1000 copolymer chains.

Topics

• impedance spectroscopy
• simulation
• copolymer
• gradient copolymer