Macromolecular Design via an Organocatalytic, Monomer-Specific and Temperature-Dependent "On/Off Switch". High Precision Synthesis of Polyester/Polycarbonate Multiblock Copolymers.

ABSTRACT: The employment of a monomer-specific "on/off switch" was used to synthesize a nine-block copolymer with a predetermined molecular weight and narrow distribution (Đ = 1.26) in only 2.5 h. The monomers consisted of a six-membered cyclic carbonate (i.e., 2-allyloxymethyl-2-ethyl-trimethylene carbonate (AOMEC)) and ε-caprolactone (εCL), which were catalyzed by 1,5,7-triazabicyclo[4.4.0]-dec-5-ene (TBD). The dependence of polymerization rate with temperature was different for the two monomers. Under similar reaction conditions, the ratio of the apparent rate constant of AOMEC and εCL [k_p^app(AOMEC)/k_p^app(εCL)] changes from 400 at T = -40 °C to 50 at T = 30 °C and 10 at T = 100 °C. Therefore, by decreasing the c

SUBMITTER: Olsen P 

PROVIDER: S-EPMC4535708 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature