Dead telechelic oligomers

To quantify the hydroxy-telechelic PMMA, LC was used to show that this two-step reaction yielded about 67% of telechelic oligomers [192], This unexpected low yield was explained by several factors during RAFT some disproportionation may occur leading to dead chains without any terminal thioesters also some side reactions occurred from aminolysis of the terminal thioester, leading to a hydrogen-terminated chain unable to be functionalized into a hydroxyl group. 

PS telechelics formed from AIBN show an end group functionality of approximatedly /=2. Moad et al. demonstrated by NMR that primary radical termination plays an important role in the formation of functional PS oligomers. The elegant gel permeation chromatography (GPC) analysis of the oligomers by Heitz and co-workers demonstrated the advantages of a flow reactor to prepare telechelics. It appears that a limited conversion of monomer (70-80%) under dead end conditions is essential to successfully prepare PS telechelics from azo initiators. ... 

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