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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 35, Number 9
BKCSDE 35(9)
September 20, 2014 

A Multisegmented Polystyrene with pH-Cleavable Linkages
Tae-Hyeon Kang, Hyung-il Lee*
ATRP, Multisegmented, Click reactions, Degradable, Polystyrene
A multisegmented polystyrene (PS) with pH-cleavable ester and carbamate linkages was successfully synthesized by a combination of atom transfer radical polymerization (ATRP) and Cu(I)-catalyzed 1,3-dipolar cycloaddition of azide and alkynes (click chemistry). ATRP was employed to synthesize polystyrene from hydroxyl-terminated initiator using CuBr/N,N,N',N'',N''-pentamethyldiethylenetriamine (PMDETA) as the catalyst. The reaction of the resulting PS with sodium azide yielded the azido-terminated polymer. The hydroxyl group in the other end of the polymer was reacted with 4-nitrophenyl chloroformate (NPC), followed by reaction with propargylamine to produce an alkyne end group with a carbamate linkage. The PS with an alkyne group in one end and an azide group in the other end was then self-coupled in the presence of CuBr/2,2'- bipyridyl (bpy) in DMF to yield a desired multisegmented PS. Molecular weight and molecular weight distribution of the self-coupled polymer increased with time, as in the typical step-growth-type polymerization processes. Finally, we demonstrated that the ester and carbamate linkages of the multisegmented PS were hydrolyzed in the presence of HCl to yield individual PS chains.
2694 - 2698
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