Atom Transfer Radical Polymerization of Methyl Acrylate with PVAc-CCl_3 Macroinitiator and a Novel Synthesis of Block Terpolymers of PVAc-b-poly(MA-co-MMA)

摘要

The atom transfer radical polymerization of methyl acrylate (MA) with poly viny-lacetate telorher (PVAc-CCI_3) as a macroinitiator and CuCI/N,N,N',N',N"-pen-tamethyldiethylenetriamine (PMDETA) as a catalyst was successfully carried out in the bulk. The reaction temperature had a direct effect on the conversion and apparent propagation rate constant (K_p~(app)) of MA polymerization reaction. In this study the apparent enthalpy of activation and enthalpy of equilibrium are 83.68 and 65.98 kJ/mol, respectively, for this polymerization reaction. In a similar polymerization system, PVAc-CCI_3 macroinitiators were used with several molecular weights, it was found that the rate of polymerization was independent of molecular weight of the macroinitiator, but the percentage of telomer used had a direct effect on the K_p~(app) of this polymerization. In all reactions studied the first order kinetics showed a linear dependence, indicating a constant number of propagating species during the polymerization. Kelen-Tuedos and Fineman-Ross linear methods were used to determine monomers chemical reactivity of methyl acrylate and methyl methacrylate in atom transfer radical polymerization. The synthesized block copolymers showed a relatively narrow molecular weight distribution (1.1 < PDI < 1.3) specific of the controlled polymerization reactions of ATRP. A broadening trend of PDI in block copolymers was observed with polymerization temperature. This work shows that it is possible to synthesis the novel block terpolymers of PVAc-b-poly(MA-co-MMA) with further narrowing in PDI which is shows that there is a chemical selectivity within the mechanism of ATRP.