Syntheses of α-bis(4-aminophenyl)-and α,ω-tetrakis(4-aminophenyl)-functionalized polymers using 1,1-bis(4-aminophenyl)ethylene in atom transfer radical polymerization reactions

摘要

The preparation of a symmetrically disubstituted 1,1-diphenylethylene derivative, 1,1-bis(4-aminophenyl)ethylene, by the Wittig reaction as well as the preparation of primary amine chain-end-functionalized polymers using that derivative in atom transfer radical polymerization (ATRP) reactions are reported. A new primary diamine initiator system was generated in situ by the atom transfer radical addition reaction of (l-bromoethyl)benzene with 1,1-bis(4-aminophenyl)ethylene in the presence of copper(l) bromide/2,2'-bipyridyl as the catalyst system and employed as the primary diamine-functionalized initiator for the polymerization of styrene by ATRP methods to produce well-defined α-bis(4-aminophenyl)-functionalized polystyrene. The polymerization kinetic data for the synthesis of α-bis(4-aminophenyl)-f unctionalized polystyrene shows that the polymerization process followed first-order rate kinetics with respect to monomer consumption. The number-average molecular weights (M_n = 1.1 x 10~3 to 13.14 x10~3 g mol~(-1)) of the α-bis(4-aminophenyl)-functionalized polymers increased linearly with percentage monomer conversion and polymers with narrow molecular weight distributions (M_w//W_n = 1.1-1.25) were obtained. The polymerization processes were monitored using gas chromatographic analyses to determine the extent of monomer consumption as a function of time. In addition, α,ω-tetrakis(4-aminophenyl)-f unctionalized polystyrene was prepared by a new, controlled/living, in situ post-ATRP chain-end functionalization reaction which involved the direct addition of 1,1-bis(4-aminophenyl)ethylene to the ω-terminus of α-bis(4-aminophenyl)-functionalized polystyrene, without the need for the isolation and purification of the polymeric precursor. The organic precursor compounds, the primary diamine-functionalized 1,1-diphenylethylene derivative and the functionalized polymers were characterized using `1H NMR, ~(13)C NMR and Fourier transform infrared spectroscopy, size exclusion chromatography, thin-layer chromatography and non-aqueous titration measurements.