Journal of Polymer Science Part A: Polymer Chemistry, Vol.40, No.3, 334-343, 2002
Synthesis of linear and starlike polymers from poly(propylene glycol) methacrylate using controlled radical polymerization
The copper-catalyzed atom transfer radical polymerization (ATRP) of poly(propylene glycol) methacrylate (PPGM) in solution to produce linear and starlike polymers is reported, using methylethyl ketone as the solvent and a temperature of 80 degreesC. The ATRP system used was efficient for polymerization of the functionalized monomer without protecting hydroxyl end groups of monomer. The polymerizations were consistent with "living" or controlled processes, as revealed by the linear evolution of molecular weight with conversion. Increasing the [M](0):[I](0) ratio resulted in increasing molecular weights, whereas the polydispersity indices remained low (M-w/M-n < 1.4) even at high conversion. Decreasing the [CuBr](0):[I](0) ratio resulted in lower conversions, slightly larger polydispersities, and decreased molecular weights, likely resulting from a lower initiation efficiency. Polymers were characterized by H-1 and C-13 NMR; molecular weights of polymers with low degrees of polymerization were estimated by end-group analysis from C-13 NMR spectra obtained using distortionless enhancement by polarization transfer and the gated decoupling techniques.
Keywords:atom transfer radical polymerization (ATRP);controlled radical polymerization;poly(propylene glycol) methacrylate;star polymers;NMR;living polymerization;kinetics