Preparation of the amphiphilic macro-rings of poly(ethylene oxide) with multi-polystyrene lateral chains and their extraction for dyes

A novel method for synthesis of amphiphilic macrocyclic graft copolymers with multi-polystyrene lateral chains is suggested, by combination of anionic ringopen polymerization (AROP) with atom transfer radical polymerization (ATRP). The anionic ring-opening copolymerization of ethylene oxide (EO) and ethoxyethyl glycidyl ether (EEGE) was carried out first using triethylene glycol and diphenylmethylpotassium (DPMK) as coinitiators; the monomer reactivity ratio of them are r_1(EO) = 1.20 ± 0.01 and r_2(EEGE) = 0.76 ±0.02 respectively. The obtained linear well-defined α,ω-dihydroxyl poly(ethylene oxide) with pendant protected hydroxylmethyls (l-poly(EO-co-EEGE)) was cyclized by reaction with tosyl chloride (TsCl) in the presence of solid KOH. The crude cyclized product containing the extended linear chain polymer was hydrolyzed and then purified by treat with α-CD. The pure cyclic copolymer with multipendant hydroxymethyls [c-poly(EO-co-Gly)] was esterified by reaction with 2-bromoisobutyryl bromide, and then used as macroinitiators to initiate polymerization of styrene (St), and a series of amphiphilic macrocyclic grafted copolymers composed of a hydrophilic PEO as ring and hydrophobic polystyrene as side chains (c-PEO-#-PS) were obtained. The intermediates and final products were characterized by GPC, NMR and MALDI-TOF in detail. The experimental results confirmed that c-PEO-PS shows stronger conjugation ability with the dyes than the corresponding comb-PEO-g-PS.