Experimental Determination of the Rate Constant of Deactivation of Poly(styrene) and Poly(butyl acrylate) Radicals in Atom Transfer Radical Polymerization

Abstract

The rate constants of deactivation in atom transfer radical polymerization of styrene and butyl acrylate have been determined. The values are k deact = 7 × 107 L mol-1 s-1 for styrene and 1 × 108 L mol-1 s-1 for butyl acrylate, both measured in p-xylene at 110 °C. The effect of solvent polarity seems to be insignificant on the basis of results measured in butyl acetate. The proper conditions for the experimental determination of k deact were found on the basis of computer simulations. Conditions were chosen such that the sensitivity of the measured rate constants toward experimental conditions and toward uncertainties in other rate parameters was minimal.

Mechanistic investigation of 9-bromoanthracene photodimers as initiators in atom transfer radical polymerization

“…Due to the extremely long reaction times required in ATRP reactions of styrene at these low temperatures (96 h for 40 8C) and the possibility of side reactions occurring over such long durations, a monomer that could be polymerized more efficiently at low temperatures was evaluated. As shown in Table 4, when n-butyl acrylate, chosen for its increased rate of polymerization compared to styrene [37], was used as the monomer at these lowered temperatures, polymers with PDI values of approximately 1.45 were obtained. Analysis of the reaction mixture using GPC (RI and UV set at 370 nm) indicated no detectable amounts of anthracene absorption in the polymer (Fig.…”

Towards understanding monomer coordination in atom transfer radical polymerization: synthesis of [CuI(PMDETA)(π-M)][BPh4] (M = methyl acrylate, styrene, 1-octene, and methyl methacrylate) and structural studies by FT-IR and 1H NMR spectroscopy and X-ray crystallography

“…½Cu I ðPMDETAÞ þ ½BPh À 4 , for which the counter-ion does not compete with monomer for coordination to Cu I , was thus studied in an effort to address the side reaction of monomer coordination to the Cu I catalyst. Third, correlating reaction parameters including activation, deactivation, initiation, overall reaction rate constants, and evolution of molecular weight distribution [41][42][43][44][45][46][47][48] with catalyst, alkyl halide, and monomer structure, solvent composition and temperature should ultimately lead to the development of more active catalysts and are crucial to any future developments of ATRP [49][50][51][52][53][54]. This paper will address the nature of the bonding in these Cu I complexes, and subsequent publications will address the quantification of this coordination process under various conditions and with Cu I (PMDETA)Br, the effect that coordination has on the reactivity of the monomer, and the performance of the catalyst in polymerization.…”

Structural and Mechanistic Aspects of Copper Catalyzed Atom Transfer Radical Polymerization

“…Other investigations include the effect of solvent, counterion, temperature, ligand/catalyst ratio, and the presence of monomer and copper(II) complexes on the activation rate constant [133,134,135,136,137,138,139] .…”

“…Additionally, deactivation rate constants ( k d ) for the more active catalysts such as Cu I X/Me 4 CYCLAM have been estimated from the initial degree of polymerization without reactivation, end functionality, and molecular weight distributions [138,141,142] . With recent advances in determination of the equilibrium constant for atom transfer ( K ATRP = k a / k d ), deactivation rate constants ( k d = k a / K ATRP ) can now be easily obtained from readily accessible activation rate constants ( k a ) [115] .…”