Development of temperature responsive polymeric gels with physical crosslinking due to intermolecular pi‐pi interactions

2021 ◽  
Author(s):  
Rishabh A. Shah ◽  
Tyler Runge ◽  
Thomas W. Ostertag ◽  
Shuo Tang ◽  
Thomas D. Dziubla ◽  
...  
Keyword(s):  
Polymeric Gels ◽  
Temperature Responsive ◽  
Pi Interactions ◽  
Physical Crosslinking

The analysis of “Gels” in polymer films

1989 ◽  
Vol 47 ◽  
pp. 362-363
Author(s):  
G. M. Brown ◽  
D. F. Brown ◽  
J. H. Butler
Keyword(s):  
Molecular Weight ◽  
Film Industry ◽  
Local Stress ◽  
Melt Index ◽  
Polyethylene Films ◽  
Crosslinked Polymer ◽  
Polymeric Gels ◽  
Mineral Particles ◽  
Polymeric Species ◽  
Special Concern

The term “gel”, in the jargon of the plastics film industry, may refer to any inclusion that produces a visible artifact in a polymeric film. Although they can occur in any plastic product, gels are a principle concern in films where they detract from the cosmetic appearance of the product and may compromise its mechanical strength by acting as local stress concentrators. Many film gels are small spheres or ellipsoids less than one millimeter in diameter whereas other gels are fusiform-shaped and may reach several centimeters in length. The actual composition of gel inclusions may vary from miscellaneous inorganics (i.e. glass and mineral particles) and processing additives to heavily oxidized, charred or crosslinked polymer. The most commonly observed gels contain polymer differing from the bulk of the sample in its melt viscosity, density or molecular weight.Polymeric gels are a special concern in polyethylene films. Over the years and with the examination of a variety of these samples three predominant polymeric species have been observed: density gels which have different crystallinity than the film; melt-index gels in which the molecular weight is different than the film and crosslinked gels which are comprised of crosslinked polyethylene.

Retrieval of resorptive human osteoclasts from temperature-responsive plastic

2016 ◽  
Author(s):  
Arjen Gebraad ◽  
Teuvo Hentunen ◽  
Tiina Laitala-Leinonen
Keyword(s):  
Temperature Responsive ◽  
Human Osteoclasts

Stereospecific 1,3-H Transfer of Indenols Proceeds via Persistent Ion-Pairs Anchored By NH···Pi Interactions

2018 ◽  
Author(s):  
David Ascough ◽  
Fernanda Duarte ◽  
Robert Paton
Keyword(s):  
Computational Analysis ◽  
Ion Pairs ◽  
Ion Pair ◽  
Hydrogen Atom Transfer ◽  
Polar Solvents ◽  
Chirality Transfer ◽  
Activation Barriers ◽  
Sense And Avoid ◽  
Phase Dynamics ◽  
Pi Interactions

The base-catalyzed rearrangement of arylindenols is a rare example of a suprafacial [1,3]-hydrogen atom transfer. The mechanism has been proposed to proceed via sequential [1,5]-sigmatropic shifts, which occur in a selective sense and avoid an achiral intermediate. A computational analysis using quantum chemistry casts serious doubt on these suggestions: these pathways have enormous activation barriers and in constrast to what is observed experimentally, they overwhelmingly favor a racemic product. Instead we propose that a suprafacial [1,3]-prototopic shift occurs in a two-step deprotonation/reprotonation sequence. This mechanism is favored by 15 kcal mol<sup>-1</sup> over that previously proposed. Most importantly, this is also consistent with stereospecificity since reprotonation occurs rapidly on the same p-face. We have used explicitly-solvated molecular dynamics studies to study the persistence and condensed-phase dynamics of the intermediate ion-pair formed in this reaction. Chirality transfer is the result of a particularly resilient contact ion-pair, held together by electrostatic attraction and a critical NH···p interaction which ensures that this species has an appreciable lifetime even in polar solvents such as DMSO and MeOH.

In Situ Crosslinking Temperature-Responsive Hydrogels with Improved Delivery, Swelling, and Elasticity for Endovascular Embolization

2019 ◽  
Author(s):  
Derek J. Overstreet ◽  
Amrita Pal ◽  
Brent L. Vernon ◽  
Elizabeth J. Lee
Keyword(s):  
Endovascular Embolization ◽  
Temperature Responsive ◽  
Responsive Hydrogels ◽  
In Situ Crosslinking

Author response for "Gelation kinetics of functionalized silica crosslinked polymeric gels used in conformance control applications"

2020 ◽  
Author(s):  
Mohamed Shamlooh ◽  
Ahmed Hamza ◽  
Ibnelwaleed A. Hussein ◽  
Mustafa S. Nasser ◽  
Saeed Salehi
Keyword(s):  
Author Response ◽  
Functionalized Silica ◽  
Conformance Control ◽  
Control Applications ◽  
Polymeric Gels ◽  
Gelation Kinetics ◽  
Kinetics Of
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