Simulation, controlled radical

Turgman-Cohen, S. and J. Genzer, Computer simulation of controlled radical polymerization Effect of chain confinement due to initiator grafting density and solvent quality in "grafting from Method. Macromolecules, 2010. 43(22) p. 9567-9577. 

Matyjaszewki et al. [229,236] pointed out the importance of the bimolecular exchange reaction (Eq. 19) to control the molecular weight and its distribution. Simulation revealed a decrease in the Mw/Mn values during polymerization, but the contribution in the actual polymerization is still ambiguous [237-240]. Reports have also addressed the importance of the decomposition of the alkoxyamine such as the disproportionation of the propagating radical and the nitroxide for the control of the polymerization [229,236,241 ]. 

Iedema, P.D. and Hoefsloot, H.C.J. (2001) Synthesis of branched polymer architectures from molecular weight and branching distributions for radical polymerisation with long-chain branching, accounting for topology-controlled random scission. Macromol. Theor. Simul., 10, 855. 

Two major entry models - the diffusion-controlled and propagation-controlled models - are widely used at present. However, Liotta et al. [28] claim that the collision entry is more probable. They developed a dynamic competitive growth model to understand the particle growth process and used it to simulate the growth of two monodisperse polystyrene populations (bidisperse system) at 50 °C. Validation of the model with on-line density and on-line particle diameter measurements demonstrated that radical entry into polymer particles is more likely to occur by a collision mechanism than by either a propagation or diffusion mechanism. 

Super-swelhng was postulated as a cause of instabihty in controlled free radical miniemulsion polymerization. Asua [312] thought that the interfacial tension used in the simulations was too high and the droplet size was too smaU. However, it is turned out that the question about droplet size is due to a misunderstanding. It is weh accepted that a well-performed miniemulsion has... 

To be fully utilized, this chamber should also serve as a resource for collaborative studies where environmental chamber measurements imder highly controlled conditions would be useful. We encourage collaboration with other researchers who have instrumentation that we lack that would be useful for various studies, such as our collaboration with William Brune of Penn State University, whose HO and HO2 radical measurement instrumentation was used with the surrogate - NOx experiments carried out for the observational based methods study. This facility would also be useful as a test bed for evaluating analytical instrumentation for use in ambient monitoring, since it can produce realistic but highly characterized simulated pollution conditions for instrument evaluation and inter-comparisons. 

Aqueous-phase photochemical peroxide production occurred in >90% of all samples at all sites, with no peroxide production in dark controls [108]. This photoproduction was hypothesized to result from the absorption of Hght by chromophores in the samples, followed by the formation of peroxyl radical intermediates, the dominant precursor of peroxides in atmospheric waters [108]. Under simulated suidight, the average rate of total peroxide photoproduction... 

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