Exploring the homogeneous controlled radical polymerisation of hydrophobic monomers in anti-solvents for their polymers: RAFT and ATRP of various alkyl methacrylates in anhydrous methanol to high conversion and low dispersity
Exploring the homogeneous controlled radical polymerisation of hydrophobic monomers in anti-solvents for their polymers: RAFT and ATRP of various alkyl methacrylates in anhydrous methanol to high conversion and low dispersity
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DOI：
10.1039/c5py00791g
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发表时间：
2015-01-01
影响因子：
4.6
通讯作者：
Rannard, S. P.
中科院分区：
文献类型：
--
作者：
Dwyer, A. B.;Chambon, P.;Rannard, S. P.
在之前的报告中，尽管甲醇被广泛认为是 p(nBuMA) 的反溶剂，但在甲基丙烯酸正丁酯 (nBuMA) 的均相 ATRP 聚合中使用无水甲醇可产生分散度低至 D = 1.02 的聚合物。在此，我们描述了使用 ATRP 和 RAFT 三种疏水性甲基丙烯酸烷基酯单体（甲基丙烯酸甲酯、甲基丙烯酸叔丁酯和甲基丙烯酸正丁酯）的均相甲醇控制自由基聚合，生成一系列均聚物、统计共聚物、两亲性嵌段共聚物和支化聚合物。比较了甲醇 ATRP 和 RAFT，RAFT 能够在这些条件下以较短的反应时间（44 小时）以非常低的分散度（D = 1.06）实现高聚合度（800 个单体单元）。聚乙二醇衍生的大分子引发剂可生成明确的 A-B 和 A-B-A 嵌段共聚物 (D = 1.02-1.18)，同时很容易合成重均分子量高达 M-w = 2.33 x 10(6) g mol(-1) 的支化 A-B 嵌段共聚物。讨论了甲醇在聚合反应中的作用。
In previous reports, the use of anhydrous methanol in the homogeneous ATRP polymerisation of n-butyl methacrylate (nBuMA) was shown to yield polymers with dispersities as low as D = 1.02, despite methanol being widely regarded as an anti-solvent for p(nBuMA). Herein, we describe the homogeneous methanolic controlled radical polymerisation of three hydrophobic alkyl methacrylate monomers (methyl, t-butyl and n-butyl methacrylate) using both ATRP and RAFT to generate a range of homopolymers, statistical copolymers, amphiliphilic block copolymers and branched polymers. Methanolic ATRP and RAFT are compared, with RAFT able to target high degrees of polymerisation (800 monomer units) with very low dispersities (D = 1.06) in shorter reaction times (44 h) under these conditions. Poly(ethylene glycol)derived macroinitiators were shown to generate well defined A-B and A-B-A block copolymers (D = 1.02-1.18) whilst branched A-B block copolymers with weight average molecular weights up to M-w = 2.33 x 10(6) g mol(-1) were readily synthesised. The role of methanol within the polymerisations is discussed.