Glycoconjugated polymer: Synthesis and characterization of poly(vinyl saccharide)-block-polystyrene-block-poly(vinyl saccharide) as an amphiphilic ABA triblock copolymer

摘要

Styrene (St) was polymerized with alpha,alpha'-bis(2',2',6,6'-tetramethyl-1'-piperidinyloxy)-1,4-diethylbenzene (1) as an initiator (bulk, [St]/[1] = 570) at 120 degrees C for 5.0 h to obtain polystyrene having 2,2,6,6-tetramethylpiperidiloxy moieties on both sides of the chain ends (2) with a number-average molecular weight (M-n) of 14,300 and a polydispersity index [weight-average molecular weightumber-average molecular weight (M-w/M-n)] of 1.14. 4-Vinylbenzyl glucoside peracetate (3a) was polymerized with 2 as a macromolecular initiator and dicumyl peroxide (DCP) as an accelerator in chlorobenzene at 120 degrees C. The polymerization with the [3a]/[2]/[DCP] ratio of 30/1/1.2 for 5 h afforded a product in a yield of 73%; it was followed by purification with preparative size exclusion chromatography to provide the ABA triblock copolymer containing the pendant acetyl glucose on both sides of the chain ends (4a; M-n = 21,000, M-w/ M-n = 1.16). Similarly, the polymerization of 4-vinylbenzyl maltobexaoside peracetate produced the ABA triblock copolymer containing the pendant acetyl maltohexaose on both side of the chain end (4b; M-n = 31,800, M-w/M-n = 1.11). Polymers 4a and 4b were modified by deacetylation into amphiphilic ABA triblock copolymers containing the pendant glucose and maltohexaose as hydrophilic segment, 5a and 5b, respectively. (c) 2006 Wiley Periodicals, Inc.