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

Abstract

AbstractThe 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 (1‐bromoethyl)benzene with 1,1‐bis(4‐aminophenyl)ethylene in the presence of copper(I) 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)‐functionalized polystyrene shows that the polymerization process followed first‐order rate kinetics with respect to monomer consumption. The number‐average molecular weights (Mn = 1.1 × 103 to 13.14 × 103 g mol−1) of the α‐bis(4‐aminophenyl)‐functionalized polymers increased linearly with percentage monomer conversion and polymers with narrow molecular weight distributions (Mw/Mn = 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)‐functionalized 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, 13C NMR and Fourier transform infrared spectroscopy, size exclusion chromatography, thin‐layer chromatography and non‐aqueous titration measurements. © 2013 Society of Chemical Industry