A facile synthesis of cleavable block copolymers via tandem polymerizations of NMRP and ATRP

作者：Tang Wei; He Junpo^*; Yang Yuliang

来源：Journal of Macromolecular Science Part A-Pure and Applied Chemistry, 2006, 43(10): 1553-1567.

DOI：10.1080/10601320600896850

• nitroxide-mediated radical polymerization (NMRP)
• atom transfer radical polymerization (ATRP)
• amphiphilic block copolymers
• tandem polymerization
• cleavable block copolymers

A functionalized compound, 4-(2-bromoisobutyryl)-2,2,6,6-tetra-methylpiperidine-1-oxyl (Br-TEMPO), was synthesized and used to synthesize block copolymers through tandem nitroxide-mediated radical polymerization (NMRP) and atom transfer radical polymerization ( ATRP). First, Br-TEMPO was used to mediate the polymerization of styrene. The kinetics of polymerization proved a typical "living" nature of the reaction and the effectiveness in the mediation of polymerization of Br-TEMPO. Then the PS-Br macroinitiator was used to initiate atom transfer radical polymerization ( ATRP). A series of acrylates were initiated by PS-Br macroinitiators in typical ATRP processes at various conditions. The controlled polymerization of ATRP was also confirmed by molecular weight and kinetic analysis. Several cleavable block copolymers of PS-b-P(t-BA), PS-b-P(n-BA), and PS-b-PMA, with different molecular weights, were synthesized via this strategy. Relatively low polydispersities (<1.5) were observed and the molecular weights were in agreement with the theoretical ones. Hydrolysis of PS-b-P( t-BA) was carried out, giving amphiphilic block copolymer PS-b-PAA without the cleavage of C-ON bond or ester bond. All the block copolymers have two T(g)s as demonstrated by DSC. A typical cleavable block copolymer of PS-b-PMA was cleaved by adding phenylhydrazine at 120 degrees C to produce homopolymers in situ.

• 出版日期2006-10
• 单位复旦大学