Block copolymers by sequential group transfer polymerization: poly(methyl methacrylate)‐block‐poly(2‐ethylhexyl acrylate) and poly(methyl methacrylate)‐block‐poly(tert‐butyl acrylate)

Abstract

AbstractPoly(methyl methacrylate)‐block‐poly(2‐ethylhexyl acrylate) (PMMA‐block‐PEHA) and poly(methyl methacrylate)‐block‐poly(tert‐butyl acrylate) with a methacrylate/acrylate unit ratio of 1:1 and 1:3, 16000 < Mn < 44000 and 1,9 < Mw/Mn < 2,5, were prepared by sequential group transfer polymerization using (1‐methoxy‐2‐methyl‐1‐propenyloxy)trimethylsilane as initiator and tetrabutylammonium fluoride monohydrate as a catalyst in tetrahydrofuran at −30°C, PMMA being the first block. The increase in Mn during the successive addition of monomers is linearly dependent on the (co)polymer yield and size‐exclusion chromatography (SEC) curves are shifted towards higher molecular weights in comparison with PMMA macroinitiators. The block structure of the copolymers was also proven by extraction experiments. The presence of homopolymers in the copolymers was not detected. When the former copolymer is prepared in a reverse way (PEHA segment being the first), the MMA polymerization ceases at ≈ 43–45% conversion.