Synthesis and Degradation Rheology and Extrusion

Cantow, H.‐J.; Bhuiyan, Abdul L.

doi:10.1007/bfb0038529

Cited by 9 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Previous studies of star-branched PI with molecular weights up to 20 kg=mole [23] reported that tethering slows down polymer relaxation by a factor of about 4, i.e., close to what is expected from a simple bead-spring, Rouse, model with the appropriate boundary conditions for a chain tethered at one end [24]. In contrast, for particle-tethered PI are 2 to 3 orders of magnitude larger than for untethered polymers.…”

supporting

confidence: 61%

“…The volume fraction of silica nanoparticles are 11.1, 5.4, and 7.4%, respectively, for the three polymer molecular weights, 3000, 5000, and 15 000 g=mol. As expected, for the untethered polymer increases with PI molecular weight [1][2][3][4]. In contrast, for tethered PI it shows no noticeable dependence, implying that the relative slowing down increases as molecular weight is lowered.…”

mentioning

confidence: 53%

“…Entanglements are topological constraints imposed on a molecule by its neighbors, which limit its side-to-side motions to the region along the polymer contour [2][3][4][5]. Edwards [6] proposed the concept of a mean-field tube to model these constraints, and de Gennes introduced the idea of reptation to explain how topologically constrained molecules relax on long time scales [7].…”

mentioning

confidence: 99%

See 2 more Smart Citations

Crowded, Confined, and Frustrated: Dynamics of Molecules Tethered to Nanoparticles

2012

View full text Add to dashboard Cite

Above a critical chemistry-dependent molecular weight, all polymer molecules entangle and, as a result, exhibit slow dynamics, enhanced viscosity, and elasticity. Herein we report on the dynamics of low molecular weight polymers tethered to nanoparticles and find that even conventionally unentangled chains manifest dynamical features similar to entangled, long-chain molecules. Our findings are shown to imply that crowding and confinement of polymers on particles produce topological constraints analogous to those in entangled systems.

show abstract

supporting

confidence: 61%

mentioning

confidence: 53%

mentioning

confidence: 99%

See 1 more Smart Citation

Crowded, Confined, and Frustrated: Dynamics of Molecules Tethered to Nanoparticles

2012

View full text Add to dashboard Cite

show abstract

Multi-chain slip-spring model for entangled polymer dynamics

Uneyama

Masubuchi

2012

The Journal of Chemical Physics

120

150

View full text Add to dashboard Cite

It has been established that entangled polymer dynamics can be reasonably described by single chain models such as tube and slip-link models. Although the entanglement effect is a result of hard-core interaction between chains, linkage between the single chain models and the real multi-chain system has not been established yet. In this study, we propose a multi-chain slip-spring model where bead-spring chains are dispersed in space and connected by slip-springs inspired by the single chain slip-spring model [A. E. Likhtman, Macromolecules 38, 6128 (2005)]. In this model the entanglement effect is replaced by the slip-springs, not by the hard-core interaction between beads so that this model is located in the niche between conventional multi-chain simulations and single chain models. The set of state variables are the position of beads and the connectivity (indices) of the slip-springs between beads. The dynamics of the system is described by the time evolution equation and stochastic transition dynamics for these variables. We propose a simple model which is based on the well-defined total free-energy and detailed balance condition. The free energy in our model contains a repulsive interaction between beads, which compensate the attractive interaction artificially generated by the slip-springs. The explicit expression of linear relaxation modulus is also derived by the linear response theory. We also propose a possible numerical scheme to perform simulations. Simulations reproduced expected bead number dependence in transitional regime between Rouse and entangled dynamics for the chain structure, the central bead diffusion, and the linear relaxation modulus.

show abstract