Functional polyolefins: Poly(ethylene)-graft-poly(tert-butyl acrylate) via atom transfer radical polymerization from a polybrominated alkane

摘要

Poly(cis-cyclooctene) is synthesized via ring-opening metathesis polymerization in the presence of a chain-transfer agent and quantitatively hydrobrominated. Subsequent graft polymerization of tert-butyl acrylate (tBA) via Cu-catalyzed atom transfer radical polymerization (ATRP) from the non-activated secondary alkyl bromide moieties finally results in PE-g-PtBA copolymer brushes. By varying the reaction conditions, a series of well-defined graft copolymers with different graft densities and graft lengths are prepared. The maximum extent of grafting in terms of bromoalkyl groups involved is approximately 80 mol. DSC measurements on the obtained graft copolymers reveal a decrease in T _m with increasing grafting density. The Cu-catalyzed atom transfer radical graft polymerization of tert-butyl acrylate from polyhydrobrominated ring-opening metathesis polymerization-derived poly(cis-cyclooctene), which structurally corresponds to polybrominated poly(ethylene), is reported. Up to 80 mol- of the non-activated bromo-groups present in the polymer can be addressed offering unique and unprecedented access to functional polyolefins. Melting points of the graft copolymers correlate with the degree of grafting.