Kinetics macromolecules

Paczkowski J, Neckers DC (1991) Twisted intramolecular charge-transfer phenomenon as a quantitative probe of polymerization kinetics. Macromolecules 24(10) 3013-3016... 

K. Admundson, E. Helfand, X. Quan, and S. D. Smith, Alignment of Lamellar Block Copolymer Microstructure in An Electric Field, 1. Alignment Kinetics," Macromolecules. 26,2698-2703 (1993). 

Amundson, K., Helfand, E., Quan, X., and Smith, S. D., Alignment of lamellar block copolymer microstructure in an electric field. 1. Alignment kinetics. Macromolecules,... 

Dry poly(methyl methacrylate) layer thickness as a function of exposure time at a light intensity of 5mW/cm. Methyl methacrylate concentrations in toluene are ( ) 1.17, ( ) 2.34, and ( ) 4.68 M. Arrows indicate the apparent mushroom-to-brush transition for the concentrations studied, and the dotted lines show the behavior of an ideal, living photopolymerization. The slopes of these lines also represent the initial growth rates of the PMMA layer. (Reprinted with permission from Rahane, S. B., et al.. Kinetics Macromolecules, 38, 8202-8210, 2005, copyright (2005) American Chemical Society.)... 

Kojima, K., Sawamoto, M. and Higashimura, T. (1989) Living cationic polymerization of isobutyl vinyl ether by hydrogen iodide/Lewis acid initiating systems effects of Lewis acid activators and polymerization kinetics. Macromolecules, 22,1552-1557, doi 10.1021/ma00194a008. 

Pagnoulle C, Konig C, Leemans L, Jerome R (2000) Reactive compatibilization of SAN/ EPR blends. 1. Dependence of the phase morphology development on the reaction kinetics. Macromolecules 33 6275-6283... 

Schonherr H, Frank CW. Ultrathin films of poly(ethylene oxides) on oxidized silicon. 1. Spectroscopic characterization of film structure and crystallization kinetics. Macromolecules 2003 36 1188-1198. 

Floudas G, Hadjichristidis N, latrou H, Pakula T, Fischer EW (1994) Microphase-separation in model 3-miktoatm star copolymers (simple graft) and terpolymers. 1. Statics and kinetics. Macromolecules 27 7735-7746... 

Penn LS, Huang H, Sindkhedkar MD, Rankin SE, Chittenden K, Quirk RP, Mathers RT, Lee Y (2002) Formation of tethered nanolayers three regimes of kinetics. Macromolecules 35 7054-7066... 

Wang, Y, Zhong, M., Zhu, W., Peng, C.-H., Zhang, Y., Konkolewicz, D., Bortolamei, N., Isse, A.A., Gennaro, A., Matyjaszewski, K. Reversible-deactivation radical polymerization in the presence of metallic copper. Comproportionation-disproportionation equilibria and kinetics. Macromolecules 46(10), 3793-3802 (2013)... 

The successful preparation of polymers is achieved only if tire macromolecules are stable. Polymers are often prepared in solution where entropy destabilizes large molecular assemblies. Therefore, monomers have to be strongly bonded togetlier. These links are best realized by covalent bonds. Moreover, reaction kinetics favourable to polymeric materials must be fast, so tliat high-molecular-weight materials can be produced in a reasonable time. The polymerization reaction must also be fast compared to side reactions tliat often hinder or preclude tire fonnation of the desired product. 

Fast transient studies are largely focused on elementary kinetic processes in atoms and molecules, i.e., on unimolecular and bimolecular reactions with first and second order kinetics, respectively (although confonnational heterogeneity in macromolecules may lead to the observation of more complicated unimolecular kinetics). Examples of fast thennally activated unimolecular processes include dissociation reactions in molecules as simple as diatomics, and isomerization and tautomerization reactions in polyatomic molecules. A very rough estimate of the minimum time scale required for an elementary unimolecular reaction may be obtained from the Arrhenius expression for the reaction rate constant, k = A. The quantity /cg T//i from transition state theory provides... 

Caution During a sininlation, solvent temperature may increase wh ile th e so In te cools. This is particii larly true of sm all solven t molecules, such as water, that can acquire high translational and rotational energies. In contrast, a macromolecule, such as a peptide, retains most of its kinetic energy in vibrational modes. This problem rem ains un solved, an d this n ote of cau tion is provided to advise you to give special care to simulations using solvent. 

The verification of theoretical data obtained by simulation of peroxide oxidation kinetics of macromolecules with experimental data, obtained from chemiluminescent analysis of blood using automated complex ChLC-1. This automated complex was developed by the authors and laboratory colleagues. 

Consequently, any association must decrease chain tendency to degradation. However, the existence of such intermediate particles at association, which possess lower height of the reaction barrier, may be probable. In this case, kinetic probabilities of the process performance increase. A sufficiently sharp increase of kinetic probabilities of the reaction must be observed in the case, if a low-molecular compound (oxygen, for example) participating in the reaction is highly stressed. But it is necessary to remember that even if kinetic probabilities of the process are increased, the reaction will also proceed in the case of its thermodynamic benefit. As association depends on macromolecule concentration, it should be taken into account at the calculation of kinetic and thermodynamic parameters of the process according to thermodynamics. 

Hence, Flory s theory offers an objective criterion for chain flexibility and makes possible to divide all the variety of macromolecules into flexible-chain (f > 0.63) and rigid-chain (f < 0.63) ones. In the absence of kinetic hindrance, all rigid-chain polymers must form a thermodynamically stable organized nematic phase at some polymer concentration in solution which increases with f. At f > 0.63, the macromolecules cannot spontaneously adopt a state of parallel order under any conditions. 

Under steady-state conditions, as in the Couette flow, the strain rate is constant over the reaction volume for a long period of time (several hours) and the system of Eq. (87) could be solved exactly with the matrix technique developed by Basedow et al. [153], Transient elongational flow, on the other hand, has two distinctive features, i.e. a short residence time (a few ps) and a non-uniform flow field, which must be incorporated into the kinetics equations. In transient elongational flow, each rate constant is a strongfunction of the strain-rate which varies with time in the Lagrangian frame moving with the center of mass of the macromolecule the local value of the strain rate for each spatial coordinate must be known before Eq. (87) can be solved. 

The parameter R in Eq. (92) can be derived empirically from the experimental SEC traces with a minimum of computational effort and without regard to the details of the degradation kinetics by using the following arguments. Once a macromolecule is fractured, the moieties are immediately driven into another region of space. Due to the decrease in MW, a considerably higher strain rate... 

Dole, M., The Radiation Chemistry of Macromolecules, Vol. 1, Academic Press, New York, 1975. David, D., Comprehensive Chemical Kinetics, Bamford, C.H. and Tiffer, C.E.H., Eds., Elsevier, Amsterdam, 1975. 

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