Macromolecular Theory and Simulations
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Materials Science Weekly Newsletter
Recently Published Articles
- Computational Modeling of Particle Fragmentation in the Heterogeneous Olefin Polymerization
Mohsen Najafi and Mahmoud Parvazinia
Article first published online: 24 OCT 2014 | DOI: 10.1002/mats.201400069
The effect of fragmentation rate of a catalyst/polymer particle and diffusivity ratio inside cracks to fragments on reaction rate and molecular weight distribution are studied. A split algorithm is developed to reduce the computational cost. In fragmentation process, the radial cracks play an important role to feed monomer into the particle to increase the reaction rate.
- Can the Branching Exponent Reliably Relate the Branching Indexes?
Article first published online: 24 SEP 2014 | DOI: 10.1002/mats.201400047
Numerically calculated values of hydrodynamic branching index in dependence of the radius-of-gyration branching index, g, obey the h3rule (data of Kurata and Fukatsu (1-4) and ours (straight line)) whereas the points of Zimm and Kilb deviate heavily (5). The value of the branching exponent equal to one appears therefore a plausible approximation.
- On Narrowing Chain-length Distributions in Ideally Dispersed Polymerization Systems
Ryszard Szymanski and Stanislaw Sosnowski
Article first published online: 21 AUG 2014 | DOI: 10.1002/mats.201400055
Confining of the polymerization system into small droplets results in narrowing of the chain-length distribution. When the number of growing chains in living polymerization equals to 2 then its variance is twice lower than of the Poisson distribution. When in irreversible step polymerization the number of remaining chains reaches 2 then polymer has a uniform (rectangle) distribution with dispersity equal to 1.33.
- Design of Copolymers Based on Sequence Distribution for a Targeted Molecular Weight and Conversion
Venkat Reddy Regatte, Hanyu Gao, Ivan A. Konstantinov, Steven G. Arturo and Linda J. Broadbelt
Article first published online: 18 AUG 2014 | DOI: 10.1002/mats.201400037
Kinetic Monte Carlo simulations allow sequence characteristics to be tallied and used in the design of copolymers with specific sequence measures as dictated by the feasible operating diagram shown here.
- An Implicit Solvent Ionic Strength (ISIS) Method to Model Polyelectrolyte Systems with Dissipative Particle Dynamics
Nan K. Li, William H. Fuss and Yaroslava G. Yingling
Article first published online: 14 AUG 2014 | DOI: 10.1002/mats.201400043
The newly developed ISIS DPD model with implicit representation of the effect of salt concentration is applied to explore the structural conformations of a long polyelectrolyte and micellization of polyelectrolyte block copolymers in aqueous solution.