1 research outputs found
Tandem Photoinduced Cationic Polymerization and CuAAC for Macromolecular Synthesis
A novel
synthetic strategy involving sequential photoinduced cationic
and copper-catalyzed azide–alkyne cycloaddition (CuAAC) click
processes for the synthesis of complex macromolecular structures such
as side-chain functional polymers, graft copolymers, and organogels
is described. In the approach, first a set of copolymers possessing
side-chain alkyne or halide functionalities, namely, polyÂ(cyclohexene
oxide-<i>co</i>-glycidyl propargyl ether) (PÂ(CHO-<i>co</i>-GPE)), polyÂ(cyclohexene oxide-<i>co</i>-epichlorohydrin)
(PÂ(CHO-<i>co</i>-ECH)), and polyÂ(tetrahydrofuran-<i>co</i>-epichlorohydrin) (PÂ(THF-<i>co</i>-ECH)), were
synthesized by photoinitiated free-radical-promoted cationic copolymerization
of the corresponding monomers using phenylbisÂ(2,4,6-trimethylbenzoyl)Âphosphine
oxide (BAPO) and diphenyl iodonium hexafluorophosphate (Ph<sub>2</sub>I<sup>+</sup>PF<sub>6</sub><sup>–</sup>) as free radical photoinitiator
and oxidant, respectively. While PÂ(CHO-<i>co</i>-GPE) readily
contained clickable alkyne side-chains, the halide groups of PÂ(THF-<i>co</i>-ECH) were converted
to azide groups by conventional azidation procedure using NaN<sub>3</sub> in DMF. Model side-chain functionalization, grafting onto,
and organogel formation were demonstrated by using PÂ(CHO-<i>co</i>-GPE) and azidated PÂ(THF-<i>co</i>-ECH) via photoinduced
CuAAC reactions. The intermediate polymers formed in various stages
and final polymers were characterized by spectral analysis and gel
permeation chromatography