posted on 2020-03-13, 14:13authored byVladimír Raus, Ana Hološ, Juraj Kronek, Jaroslav Mosnáček
2-Isopropenyl-2-oxazoline
(IPOx) is an important double functional
monomer with multiple potential applications. However, until now,
the attempts at reversible-deactivation radical polymerization (RDRP)
of IPOx via its double bond have met with little success, leading
to low conversions and high-dispersity products. Here, we demonstrate
that IPOx can be polymerized through aqueous Cu(0)-mediated RDRP in
a controlled way using the 2-chloropropionitrile/CuCl(CuCl2)/TPMA initiation and catalytic system and 0.67 M NaCl as a solvent.
It is shown that the polymerization is highly sensitive to the initiator
concentration and the CuCl/CuCl2 ratio; however, with careful
optimization of the polymerization parameters, low-dispersity products
can be obtained at quantitative conversions. The synthesized poly(IPOx)
polymers were subsequently transformed into different ATRP macroinitiators
by the reaction of the pendant 2-oxazoline units with 2-bromoisobutyric
or 2-chloropropionic acid under optimized reaction conditions. Styrene
and methyl methacrylate were then grafted as model monomers from these
macroinitiators under ATRP conditions, confirming that defined poly(IPOx)-based
graft copolymers with controlled grafting density and molecular weights
of the poly(IPOx) backbone and of the grafts are accessible by the
presented method. This provides a straightforward route to a new class
of 2-oxazoline-based materials.