Synthesis of amphiphilic triblock copolymer of polystyrene and poly(4-vinylbenzyl glucoside) via TEMPO-mediated living radical polymerization

Abstract

4-Vinylbenzyl glucoside peracetate 1 was polymerized with α,α′-bis(2′,2′,6′,6′-tetramethyl-1′-piperidinyloxy)-1,4-diethylbenzene 2 in chlorobenzene using (1 S)-(+)-10-camphorsulfonic acid anhydrous (CSA) as an accelerator ([ 1]=0.4 M,[ 1]/[ 2]/[CSA]=75/1/1.3) at 125 °C for 5 h. The polymerization afforded poly(4-vinylbenzyl glucoside peracetate) having TEMPO moieties on both sides of the chain ends, 3, with a molecular weight ( M w,SLS) of 8500, a polydispersity index ( M w/ M n) of 1.09, and an average degree of polymerization of the 1 unit ( x) of 17. Styrene (St) was polymerized with 3 in chlorobenzene at 125 °C (St/chlorobenzene=1/2, w/w). The polymerization successfully afforded polystyrene–poly(4-vinyl glucoside peracetate)–polystyrene, 4, when the polymerization time was below about 2 h. Polymer 4 with the M w,SLS of 12,500, 17,900, and 29,400, the compositions ( y– x– y) of 20–17–20, 45–17–45, and 100–17–100, and the M w/ M n of 1.12, 1.14 and 1.17 were modified by deacetylation using sodium methoxide in dry-THF into polystyrene–poly(4-vinyl glucoside peracetate)–polystyrene, 5. The solubility of polymer 5 was examined using a good solvent for polystyrene such as toluene and for the saccharide such as H 2O.