Percolation of Trace Amounts of Linear Polymers in Melts of Cyclic Polymers

Vasquez, Rafael; Shanbhag, Sachin

doi:10.1002/mats.201000080

Cited by 14 publications

(22 citation statements)

References 28 publications

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“…by threading the rings configuration, as noted in [25][26][27], hence decreasing the exponent of η 0,linear /η 0,ring . More experimental data is necessary to quantify the role of the contaminants and estimate the coefficient of the pure melt of rings more accurately.…”

Section: Resultsmentioning

confidence: 98%

Understanding the dynamics of rings in the melt in terms of the annealed tree model

Smrek

Grosberg

2015

J. Phys.: Condens. Matter

120

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Dynamical properties of a long polymer ring in a melt of unknotted and unconcatenated rings are calculated. We re-examine and generalize the well known model of a ring confined to a lattice of topological obstacles in the light of the recently developed Flory theory of unentangled rings which maps every ring on an annealed branched polymer and establishes that the backbone associated with each ring follows self-avoiding rather than Gaussian random walk statistics. We find the scaling of ring relaxation time and diffusion coefficient with ring length, as well as time dependence of stress relaxation modulus, zero shear viscosity and mean square averaged displacements of both individual monomers and ring's mass center. Our results agree within error bars with all available experimental and simulations data of the ring melt, although the quality of the data so far is insufficient to make a definitive judgment for or against the annealed tree theory. In the end we review briefly the relation between our findings and experimental data on chromatin dynamics.

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Section: Resultsmentioning

confidence: 98%

Understanding the dynamics of rings in the melt in terms of the annealed tree model

Smrek

Grosberg

2015

J. Phys.: Condens. Matter

120

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“…Therefore, these threading effects that connect ring and linear chains constitute long lived entanglements which represent strong topological interactions that are capable of slowing down relaxation and chain mobility. 1,[34][35][36][37][38][39][40][41] In view of the above explained arguments, a threading effect of C-PCL by L-PCL chains reduces the spherulitic growth rates of ring PCL molecules, as shown in Fig. 6.…”

Section: Spherulitic Growth Rates Determined By Plommentioning

confidence: 90%

The influence of small amounts of linear polycaprolactone chains on the crystallization of cyclic analogue molecules

et al. 2016

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Cyclic poly(3-caprolactone) model chains (C-PCL) were synthesized by a ring closure click chemistry technique. Identical linear precursors (L-PCL) of equivalent molecular lengths were also prepared. The effect of adding small amounts of linear (L-PCL) to cyclic analogs (C-PCL) was studied by preparing blends (C/L) in solution of the following composition range: 95/5, 90/10 and 80/20. Two sets of blends with PCL samples of different number average molecular weights (3 and 12 kg mol À1 ) were studied. The blends were analyzed by polarized light optical microscopy (PLOM) and advanced Differential Scanning Calorimetry (DSC) techniques that included non-isothermal and isothermal crystallization studies and thermal fractionation by SSA (Successive Self-nucleation and Annealing). The results show that addition of small amounts of linear chains (i.e., 5 and 10 wt%) to cyclic PCLs produces synergistic decreases in crystallization and melting temperatures, crystallinity degrees and isothermal crystallization rates (for both 3 and 12 kg mol À1 samples). When the amount of linear chains reaches 20 wt%, a significant recovery of a simple mixing law behavior is obtained. Thermal fractionation demonstrated that the addition of linear chains can reduce the annealing capacity of cyclic chains. The behavior of the C/L blends can be explained by the threading of ring molecules by linear chains. This threading effect amounts to an increase in entanglement density that reduces chain diffusion and hence crystallization rate.

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“…The threading effects constitute strong topological interactions capable of slowing down relaxation and chain mobility, because they represent long-lasting entanglements. Therefore, cyclic molecules relax and diffuse more slowly than anticipated by composition effects, as a result of the presence of small amounts of linear chains [146][147][148][149][150][151].…”

Section: Reasons For Different Behavior Reported In the Literaturementioning

confidence: 94%

“…According to Kapnistos et al [33], the form of the stress relaxation modulus at intermediate times is affected by this network, producing an entanglement plateau instead of power law behavior. Moreover, in blends of linear and cyclic molecules, the trend of cyclic molecules to be threaded by linear chains has been shown by computer simulations [146][147][148][149][150][151]. The threading effects constitute strong topological interactions capable of slowing down relaxation and chain mobility, because they represent long-lasting entanglements.…”

Section: Reasons For Different Behavior Reported In the Literaturementioning

confidence: 96%

Crystallization of Cyclic Polymers

Pérez-Camargo

Múgica

Zubitur

et al. 2015

Polymer Crystallization I

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The effect of chain topology (ring versus linear polymer chains) on polymer crystallization is reviewed. Recent advances in ring closure and ring expansion synthetic techniques have made available a range of well-characterized samples with higher levels of purity than available decades ago. Cyclic molecules are fascinating because the structural difference between them and linear chains is relatively small, yet their behavior can be completely different from that of their linear analogs of identical chain length. The effect of having no chain ends can dramatically change the polymer coil conformation and diffusion rate, as well as the chain entanglement density in the melt. These changes are reflected in different nucleation and crystallization kinetics for cyclic and linear polymeric chains. However, the results published so far seem to be dependent on the type of polymer employed. Therefore, a careful look at the literature and evidence reported for each group of materials has been assembled and compared. The possible reasons for some of the contradictions in the evidence are also discussed.

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Percolation of Trace Amounts of Linear Polymers in Melts of Cyclic Polymers

Cited by 14 publications

References 28 publications

Understanding the dynamics of rings in the melt in terms of the annealed tree model

Understanding the dynamics of rings in the melt in terms of the annealed tree model

The influence of small amounts of linear polycaprolactone chains on the crystallization of cyclic analogue molecules

Crystallization of Cyclic Polymers

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