Photochemical Properties of Propargylamine-based Polymers

Propargylamines are a promising but quite poorly studied category of organic compounds. This work aimed to study the photochemical properties of propargylamines polymers containing porphyrin fragments with electron transfer reactions. The study was carried out in 2019 at the Institute of Organic Chemistry (RAS, Moscow, Russia). The obtained polymer was irradiated with a luminous source. The absorption spectra were studied by electron paramagnetic resonance using a radio spectrometer. The presence of porphyrin and propargylamine in the polymer solution has been established to promote the reaction of complexation. This is due to the presence of double bonds in the amino groups, whereas also porphyrin and bromanil, which is an electron acceptor. The resulting data allow explaining the processes involved in photochemical reactions during the irradiation of the porphyrin complex in the presence of bromanil. In the long-wavelength part of the spectrum (above 540 nm), electron phototransfer inside the polymer molecule to the porphyrin side and between molecules from the porphyrin anion radical to the neutral polymer molecule take place.

3. Sliminess and stickiness

‘Sliminess and stickiness’ examines the molecular origin of ‘stickiness’. It details Hermann Staudinger’s research on ‘double bonds’ and ‘macromolecules’. Understanding the unorthodox properties of the polymer liquid and gel state turned out to be one of the first successes of soft matter science. Staudinger faced a challenge: how much space would a polymer molecule occupy when in solution? Many of the mathematical techniques that had been developed to deal with the quantum mechanics of electrons, photons, and their interaction in solids could be translated into tools for solving polymer problems such as this one. The properties of rubber, and the sticky sliminess of rubbery liquids, are topics which relate to the notion of stickiness.

Polyacrylamide Adsorption and Readsorption in Sandstone Porous Media

Summary The term polymer retention describes all mechanisms that remove the polymer from the flowing solution, with adsorption being its primary cause. This phenomenon can lead to detrimental effects during polymer enhanced oil recovery (EOR). In this paper, we present an investigation of dynamic polymer adsorption in sandstone-outcrop cores using polymer solutions. We study the effects of permeability and polymer concentration on the adsorption under two conditions: on virgin cores (adsorption) and a previously polymer-flooded core (readsorption). According to the results, two concentration plateaus and two regions of concentration-dependent adsorption characterize the polymer adsorption in a virgin porous medium, following a proposed Type IV isotherm. The transition between the first plateau and the second adsorption region occurs near to the overlapping concentration from dilute to semidilute regimes (cp*). Polymer readsorption increases slightly with the successive injection of banks with a higher polymer concentration, following a Type I (Langmuir) isotherm. For that case, we propose a readsorption mechanism on the basis of the desorption of a polymer molecule section and the adsorption of a new free polymer molecule. The adsorption and readsorption isotherms are similar until cp*, while the adsorption is much higher than readsorption for concentrations higher than cp*. Therefore, if the polymer concentration of the mobility control bank is greater than cp*, the total polymer loss during field applications can be reduced by preinjecting a polymer bank of lower concentration.

Influence of polyacrylamide conformation on fabric of “tunable” kaolin–polymer composite

“Tunable” clay–polymer composites have the potential to improve the engineering properties of clay materials. The importance of these materials derives from the ability of the responsive polymer to adopt various conformations (coiled, partially extended or extended), which in turn impacts the mesoscale properties of the material. However, the influence of polymer molecule conformation on particle arrangement and overall composite behavior is not well understood. The purpose of this study is to understand the fabric development due to the conformational behavior of the polymer, and thus the clay–polymer composite, over a wide range of solids content and stress levels. The polymer molecule conformation was controlled using selected fluid pH and ionic concentrations. Results show that the polymer conformation significantly influences clay fabric formation. When the polymer molecules are likely to have extended conformation, the dominant fabric mode is face-to-face and particle mobilization increases. Both face-to-face and edge-to-edge fabric formation dominate the behavior of the composite when coiled conformation is likely, resulting in a decrease in interparticle movement. Thus, the polymer conformation can be used to manipulate both the interparticle spacing between particles and (or) aggregates and arrangement of particles.