Synthesis of poly(dimethylsiloxane)‐containing diblock and triblock copolymers by the combination of anionic ring‐opening polymerization of hexamethylcyclotrisiloxane and nitroxide‐mediated radical polymerization of methyl acrylate, isoprene, and styrene

Abstract

Poly(dimethylsiloxane)‐containing diblock and triblock copolymers were prepared by the combination of anionic ring‐opening polymerization (AROP) of hexamethylcyclotrisiloxane (D3) and nitroxide‐mediated radical polymerization (NMRP) of methyl acrylate (MA), isoprene (IP), and styrene (St). The first step was the preparation of a TIPNO‐based alkoxyamine carrying a 4‐bromophenyl group. The alkoxyamine was then treated with Li powder in ether, and AROP of D3 was carried out using the resulting lithiophenyl alkoxyamine at room temperature, giving functional poly(D3) with Mw/Mn of 1.09–1.16. NMRPs of MA, St, and IP from the poly(D3) at 120 °C gave poly(D3‐b‐MA), poly(D3‐b‐St), and poly(D3‐b‐IP) diblock copolymers, and subsequent NMRPs of St from poly(D3‐b‐MA) and poly(D3‐b‐IP) at 120 °C gave poly(D3‐b‐MA‐b‐St) and poly(D3‐b‐IP‐b‐St) triblock copolymers. The poly(dimethylsiloxane)‐containing diblock and triblock copolymers were analyzed by 1H NMR and size exclusion chromatography. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6153–6165, 2005

In situ generation of nitroxide from alkoxyamines for controlled acrylate polymerization

“…Such structured polymers, including block, graft, and more highly branched macromolecules, have traditionally been prepared by living ionic polymerization techniques 1–4. In recent years, radical polymerization methods with many of the characteristics of living polymerizations have increasingly been used in the preparation of novel polymer architectures 5–22. These methods have facilitated the preparation of a wide range of polymer structures, many of which would be difficult if not impossible to prepare through more traditional living ionic polymerization methods.…”

“…Nitroxide‐mediated radical polymerization, as one of these controlled radical polymerization methods, has held great promise for the preparation of many interesting polymer architectures since its initial development in the late 20th century 5, 11, 12, 23–25. Its widespread adoption has been limited by a number of issues: a limited range of monomers, not including methacrylates, is polymerizable; high temperatures and long reaction times are generally necessary due to the high CO bond strength in the dormant alkoxyamine species; and preparation of useful nitroxides and alkoxyamine initiators is not always trivial.…”

Polydimethylsiloxane macromonomer bearing N‐vinylcaprolactam as end group: thermosensitive graft copolymers via free radical polymerization

“…Certain properties of PDMS, e.g. low glass transition temperature, low surface energy, selective gas permeability, excellent thermal and oxidative stability, low solubility parameter and sufficient biocompatibility, are some of the reasons for its many industrial applications …”

Synthesis of graft copolymer by ATRP of MMA from poly(phenylacetylene)

“…In a previous report17 we described the nitroxide‐mediated radical polymerization (NMRP) of styrene (St) from the poly(PA) in the cis ‐transoid form. The combination of living radical polymerization and other polymerization techniques provide a variety of well‐defined polymeric architectures 18–26. Since the NMRP of St from the poly(PA) was carried out at 120 °C, the complete isomerization from the cis ‐transoid to trans ‐transoid forms took place during the polymerization to give a densely grafted comb structure consisting of a rigid poly(PA) and flexible poly(St) side chain.…”

“…The combination of living radical polymerization and other polymerization techniques provide a variety of well-defined polymeric architectures. [18][19][20][21][22][23][24][25][26] Since the NMRP of St from the poly(PA) was carried out at 120 8C, the complete isomerization from the cis-transoid to trans-transoid forms took place during the polymerization to give a densely grafted comb structure consisting of a rigid poly(PA) and flexible poly(St) side chain. If the poly(PA) maintains the cis-transoid form during the living radical polymerization, it is expected that the resultant graft copolymer would have a centipede-like structure which consists of a rigid poly(PA) backbone and flexible vinyl polymer side chains.…”