Dilute Solution Viscoelasticity of Simple Ionic Polymers—A Theory for Charged Bead‐Spring Models

1972 ◽  
Vol 57 (1) ◽  
pp. 482-491 ◽  
Author(s):  
M. King ◽  
A. Eisenberg
Keyword(s):  
Dilute Solution ◽  
Ionic Polymers

Computer averaging of lattice images of poly-4-methyl-pentene-1 (P4mp1): Noise created artifacts

1987 ◽  
Vol 45 ◽  
pp. 388-389
Author(s):  
P. Pradère ◽  
J.F. Revol ◽  
R. St. John Manley
Keyword(s):  
Low Dose ◽  
Polymer Concentration ◽  
Processing System ◽  
Limiting Factor ◽  
Dilute Solution ◽  
New Techniques ◽  
Dose Unit ◽  
Lattice Images ◽  
Dose Imaging ◽  
Imaging Conditions

Although radiation damage is the limiting factor in HREM of polymers, new techniques based on low dose imaging at low magnification have permitted lattice images to be obtained from very radiation sensitive polymers such as polyethylene (PE). This paper describes the computer averaging of P4MP1 lattice images. P4MP1 is even more sensitive than PE (total end point dose of 27 C m-2 as compared to 100 C m-2 for PE at 120 kV). It does, however, have the advantage of forming flat crystals from dilute solution and no change in d-spacings is observed during irradiation.Crystals of P4MP1 were grown at 60°C in xylene (polymer concentration 0.05%). Electron microscopy was performed with a Philips EM 400 T microscope equipped with a Low Dose Unit and operated at 120 kV. Imaging conditions were the same as already described elsewhere. Enlarged micrographs were digitized and processed with the Spider image processing system.

Two-stage self-seeding method for preparation of single crystals of poly(phenylene sulfide)

1989 ◽  
Vol 47 ◽  
pp. 368-369
Author(s):  
Sengshiu Chung ◽  
Peggy Cebe
Keyword(s):  
Single Crystals ◽  
High Performance ◽  
Dilute Solution ◽  
Two Stage ◽  
Annealing Behavior ◽  
High Performance Polymers ◽  
Seeding Method ◽  
Phenylene Sulfide

We are studying the crystallization and annealing behavior of high performance polymers, like poly(p-pheny1ene sulfide) PPS, and poly-(etheretherketone), PEEK. Our purpose is to determine whether PPS, which is similar in many ways to PEEK, undergoes reorganization during annealing. In an effort to address the issue of reorganization, we are studying solution grown single crystals of PPS as model materials.Observation of solution grown PPS crystals has been reported. Even from dilute solution, embrionic spherulites and aggregates were formed. We observe that these morphologies result when solutions containing uncrystallized polymer are cooled. To obtain samples of uniform single crystals, we have used two-stage self seeding and solution replacement techniques.

Mapping the “Extra Solvent Power, ESP” of Ionic Liquids for Monomers, Polymers and Globular Nanoparticles

2017 ◽  
Author(s):  
Jose A. Pomposo
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Linear Polymers ◽  
Green Solvents ◽  
Ionic Polymers ◽  
First Time ◽  
Solvent Power

Understanding the miscibility behavior of ionic liquid (IL) / monomer, IL / polymer and IL / nanoparticle mixtures is critical for the use of ILs as green solvents in polymerization processes, and to rationalize recent observations concerning the superior solubility of some proteins in ILs when compared to standard solvents. In this work, the most relevant results obtained in terms of a three-component Flory-Huggins theory concerning the “Extra Solvent Power, ESP” of ILs when compared to traditional non-ionic solvents for monomeric solutes (case I), linear polymers (case II) and globular nanoparticles (case III) are presented. Moreover, useful ESP maps are drawn for the first time for IL mixtures corresponding to case I, II and III. Finally, a potential pathway to improve the miscibility of non-ionic polymers in ILs is also proposed.

scholarly journals Cover Feature: Solvent‐Free Mechanochemical Post‐Polymerization Modification of Ionic Polymers (ChemSusChem 18/2021)

ChemSusChem ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 3633-3633
Author(s):  
Joo Won Lee ◽  
Jihye Park ◽  
Joonhee Lee ◽  
Sora Park ◽  
Jeung Gon Kim ◽  
...  
Keyword(s):  
Solvent Free ◽  
Ionic Polymers

scholarly journals Investigation of Ring and Star Polymers in Confined Geometries: Theory and Simulations

Entropy ◽  
2021 ◽  
Vol 23 (2) ◽  
pp. 242
Author(s):  
Joanna Halun ◽  
Pawel Karbowniczek ◽  
Piotr Kuterba ◽  
Zoriana Danel
Keyword(s):  
Star Polymers ◽  
Polymer Chains ◽  
The Other ◽  
Nano Particles ◽  
Dilute Solution ◽  
Confined Geometries ◽  
Density Profiles ◽  
Ideal Ring ◽  
Ring Polymer ◽  
Monomer Density

The calculations of the dimensionless layer monomer density profiles for a dilute solution of phantom ideal ring polymer chains and star polymers with f=4 arms in a Θ-solvent confined in a slit geometry of two parallel walls with repulsive surfaces and for the mixed case of one repulsive and the other inert surface were performed. Furthermore, taking into account the Derjaguin approximation, the dimensionless layer monomer density profiles for phantom ideal ring polymer chains and star polymers immersed in a solution of big colloidal particles with different adsorbing or repelling properties with respect to polymers were calculated. The density-force relation for the above-mentioned cases was analyzed, and the universal amplitude ratio B was obtained. Taking into account the small sphere expansion allowed obtaining the monomer density profiles for a dilute solution of phantom ideal ring polymers immersed in a solution of small spherical particles, or nano-particles of finite size, which are much smaller than the polymer size and the other characteristic mesoscopic length of the system. We performed molecular dynamics simulations of a dilute solution of linear, ring, and star-shaped polymers with N=300, 300 (360), and 1201 (4 × 300 + 1-star polymer with four arms) beads accordingly. The obtained analytical and numerical results for phantom ring and star polymers are compared with the results for linear polymer chains in confined geometries.

scholarly journals Lifetime predictions of non-ionic and ionic biopolymers: kinetic studies by non-isothermal thermogravimetric analysis

2021 ◽  
Author(s):  
Martina Maria Calvino ◽  
Lorenzo Lisuzzo ◽  
Giuseppe Cavallaro ◽  
Giuseppe Lazzara ◽  
Stefana Milioto
Keyword(s):  
Degradation Kinetics ◽  
Kinetic Studies ◽  
Ionic Polymers ◽  
Heating Rates ◽  
Exponential Factor ◽  
Master Plot ◽  
Plot Analysis ◽  
Sustainable Polymers ◽  
Master Plot Analysis

AbstractIn this paper, films based on sustainable polymers with variable charge have been investigated by non-isothermal thermogravimetry in order to predict their lifetime, which is a key parameter for their potential use in numerous technological and biomedical applications. Specifically, chitosan has been selected as positively charged biopolymer, while alginate has been chosen as negatively charged biopolymer. Among non-ionic polymers, methylcellulose has been investigated. Thermogravimetric measurements at variable heating rates (5, 10, 15 and 20 °C min−1) have been performed for all the polymers to study their degradation kinetics by using isoconversional procedures combined with ‘Master plot’ analyses. Both integral (KAS and Starink methods) and differential (Friedman method) isoconversional procedures have shown that chitosan possesses the highest energetic barrier to decomposition. Based on the Master plot analysis, the decomposition of ionic polymers can be described by the R2 kinetic model (contracted cylindrical geometry), while the degradation of methylcellulose reflects the D2 mechanism (two-dimensional diffusion). The determination of both the decomposition mechanism and the kinetic parameters (activation energy and pre-exponential factor) has been used to determine the decay time functions of the several biopolymers. The obtained insights can be helpful for the development of durable films based on sustainable polymers with variable electrostatic characteristics. Graphical abstract

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