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Abstract: A simple polymerization scheme has been studied introducing small modifications leading to a stable focus type steady state (with damped oscillations) or unstable focus type (which combined with a no return enclosure for phase trajectories will show cycle limit sustained oscillations). Two variables have been employed in this analysis: X∝ monomer, . Limit cycle oscillations requires the addition of autocatalysis with respect to the monomer, J+X→2X, and so does an “enzymatic” block assuming that . The combination of both collateral additions makes the steady state an unstable focus and allows a simple Poincaré–Bendixson proof for the existence of the limit cycle. [ABSTRACT FROM AUTHOR]

A simple radical polymerization is proposed in this paper, with step-by-step chain growth (Ri + M → Ri+1), and termination by transfer to a third body (Ri + S → polymer) such as the solvent. It is assumed that, for a certain critical degree of polymerization n, the propagator Rn reacts with substrate H to produce a deactivator (V) of the first propagator (H + Rn → Rn + V; V + R1 → P1) R1. Assuming that monomer, M, and precursor concentrations are constant, and assuming that the deactivator reaches fast a steady state, the resulting kinetic equations are formally linear, but they admit, perturbations rj(t) of the steady-state concentrations of the propagators R1, R2, ..., Rn, which are periodic functions of time. Even more, they can be purely sinusoidal functions (which have been called “harmonic,” in analogy to the solutions of the well-known classical harmonic oscillator) with phase shift between perturbations rj(t) = Rj- (Rj)0 and rj+1(t) = Rj+1 - (Rj+1)0. Based on these periodic solutions and aiming to a model as simple as possible, a theoretical analysis is made, resulting in that the minimum value for n would be n = 3. Of course, these harmonic oscillations “driven by trimer” are equally found in the group of all the remaining propagators with polymerization degree higher than 3 (variable Y = ∑∞j=4 Rj). © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 507–511, 2009 [ABSTRACT FROM AUTHOR]

This article discusses a study on the spectroscopic characterization of poly(acryloxyethyl-trimethylammonium chlo-ride-co-2-hydroxyethyl methacrylate) [poly(Q-co-H)]. The study used potassium persulfate as initiator in preparing poly(Q-co-H by free radical polymerization in an aqueous solution. It determined the molar fractions of acryloxyethyl-tri-methylammonium chloride monomer units incorporated in the copolymers.

Abstract: The polymerization of n-hexyl methacrylate (n-HMA) in three-component microemulsion stabilized with dodecyltrimethylammonium bromide (DTAB) is reported as a function of monomer and initiator concentrations and temperature. The obtained latices were bluish, transparent, and translucent. Particle sizes and molar masses were on the order of 20 nm and , respectively. In all cases, high reaction rates and final conversions of 98% were obtained. Polymerization temperature has a strong effect on reaction rate and conversion. [Copyright &y& Elsevier]