Bio-based ABA triblock copolymers with central degradable moieties

A set of (poly-alpha-methylene-gamma-butyrolactone)-co-(poly-delta-decalactone)-co-(poly-alpha-methylene-gamma-butyrolactone) (PMBL-co-PDL-co-PMBL) ABA block copolymers containing different stimuli cleavable groups at the central point of the poly(delta-decalactone) (PDL) block were synthesized by a combination of Ring Opening Transesterification Polymerization (ROTEP) of DL, diol end-group functionalization as alpha-bromoester and Atom Transfer Radical Polymerization (ATRP) of alpha-methylene-gamma-butyrolactone (MBL). Diols containing acetal, spiroacetal, thioacetal and disulphide units were used as initiators for the bulk room temperature controlled polymerization of delta-decalactone (DL) using 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as catalyst. PDL diols were functionalized in a one-pot two-steps procedure using N-(2-bromoisobutyryl)imidazole (BiB-Im). The resulting macroinitiators were chain extended by atom transfer radical polymerization (ATRP) in DMF at 50 degrees C using MBL as methacrylic-like monomer and the conventional CuCl/CuCl2/2,2'-bipyridine catalyst system. The cleavage behaviour of the copolymers under reductive, acidic and photooxidative conditions has been studied and the resulting AB block copolymers structurally characterized.U

Automated summary

A series of ABA triblock copolymers containing different stimuli-cleavable groups at the central point of the δ-decalactone block were synthesized. The cleavage behavior of these copolymers under reductive, acidic and photooxidative conditions was studied and their structures were characterized.