Polymers

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13 pages, 1888 KiB

Open AccessArticle

Adsorptive Removal of Anionic Azo Dye New Coccine Using Silica and Silica-gel with Surface Modification by Polycation

by Tien Duc Pham, Viet Phuong Bui, Thuy Nga Pham, Thi Mai Dung Le, Kim Thuy Nguyen, Van Hoi Bui and The Dung Nguyen

Polymers 2021, 13(10), 1536; https://doi.org/10.3390/polym13101536 - 11 May 2021

Cited by 15 | Viewed by 2713

Abstract

In the present work, adsorption of anionic azo dye, new coccine (NCC) on silica and silica-gel in an aquatic environment was discovered. Effective conditions such as adsorption time, pH, the influence of dosage on NCC adsorption using strong polycation, poly-diallyl-dimethylammonium chloride (PDADMAC) modified [...] Read more.

In the present work, adsorption of anionic azo dye, new coccine (NCC) on silica and silica-gel in an aquatic environment was discovered. Effective conditions such as adsorption time, pH, the influence of dosage on NCC adsorption using strong polycation, poly-diallyl-dimethylammonium chloride (PDADMAC) modified silica (PMS) and PDADMAC modified silica-gel (PMSG) were systematically studied. The removal of NCC using PMS and PMSG were much higher than that using raw silica and silica-gel without PDADMAC in all pH ranges from 3 to 10. The adsorption of NCC onto PMS and PMSG was achieved maxima at the same conditions of contact time 30 min, pH 6. The optimum adsorbent dosages of PMS and PMSG for NCC removal were 10 and 20 mg·mL⁻¹, respectively. Experimental results of NCC adsorption isotherms onto PMS and PMSG at different ionic strength were fitted by Langmuir and Freundlich models. The NCC removal efficiencies using PMS and PMSG were higher than 87%, indicating that PMS and PMSG are novel and reusable adsorbents for removal of anionic dye. Based on adsorption isotherms, and surface group changes after PDADMAC modification and NCC adsorption examined by Fourier transform infrared spectroscopy (FTIR), we demonstrate that electrostatic interaction between positively charged adsorbents’ surfaces and negative sulfonic groups of NCC are the main driving force for anionic azo dye adsorption onto PMS and PMGS adsorbents. Full article

(This article belongs to the Special Issue Polymers and Nanomaterials: Interactions and Applications)

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13 pages, 2938 KiB

Open AccessArticle

RETRACTED: Hybrid Application of Nanoparticles and Polymer in Enhanced Oil Recovery Processes

by Yanqiu Hu, Zeyuan Zhao, Huijie Dong, Maria Vladimirovna Mikhailova and Afshin Davarpanah

Polymers 2021, 13(9), 1414; https://doi.org/10.3390/polym13091414 - 27 Apr 2021

Cited by 28 | Viewed by 3491 | Retraction

Abstract

Nowadays, the addition of nanoparticles to polymer solutions would be of interest; however, the feasible property of nanoparticles and their impact on oil recovery has not been investigated in more detail. This study investigates the rheology and capillary forces (interfacial tension and contact [...] Read more.

Nowadays, the addition of nanoparticles to polymer solutions would be of interest; however, the feasible property of nanoparticles and their impact on oil recovery has not been investigated in more detail. This study investigates the rheology and capillary forces (interfacial tension and contact angle) of nanoparticles in the polymer performances during oil recovery processes. Thereby, a sequential injection of water, polymer, and nanoparticles; Nanosilica (SiO₂) and nano-aluminium oxide (Al₂O₃) was performed to measure the oil recovery factor. Retention decrease, capillary forces reduction, and polymer viscoelastic behavior increase have caused improved oil recovery due to the feasible mobility ratio of polymer–nanoparticle in fluid loss. The oil recovery factor for polymer flooding, polymer–Al₂O₃, and polymer–SiO₂ is 58%, 63%, and 67%, respectively. Thereby, polymer–SiO₂ flooding would provide better oil recovery than other scenarios that reduce the capillary force due to the structural disjoining pressure. According to the relative permeability curves, residual oil saturation (S_or) and water relative permeability (K_rw) are 29% and 0.3%, respectively, for polymer solution; however, for the polymer–nanoparticle solution, S_or and K_rw are 12% and 0.005%, respectively. Polymer treatment caused a dramatic decrease, rather than the water treatment effect on the contact angle. The minimum contact angle for water and polymer treatment are about 21 and 29, respectively. The contact angle decrease for polymer treatment in the presence of nanoparticles related to the surface hydrophilicity increase. Therefore, after 2000 mg L⁻¹ of SiO₂ concentration, there are no significant changes in contact angle. Full article

(This article belongs to the Special Issue Polymers and Nanomaterials: Interactions and Applications)

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16 pages, 5598 KiB

Open AccessEditor’s ChoiceArticle

Poly(Vinyl Chloride) Spheres Coated with Graphene Oxide Sheets: From Synthesis to Optical Properties and Their Applications as Flame-Retardant Agents

by Mihaela Baibarac, Luiza Stingescu, Malvina Stroe, Catalin Negrila, Elena Matei, Liviu C. Cotet, Ion Anghel, Ioana E. Şofran and Lucian Baia

Polymers 2021, 13(4), 565; https://doi.org/10.3390/polym13040565 - 14 Feb 2021

Cited by 18 | Viewed by 3208

Abstract

A new method to obtain poly(vinyl chloride) (PVC) spheres, which consists of an interaction between commercial PVC grains and hexyl ethyl cellulose and lauroyl peroxide at a temperature of 60 °C, is reported. The addition of the graphene oxide (GO) sheets dispersed in [...] Read more.

A new method to obtain poly(vinyl chloride) (PVC) spheres, which consists of an interaction between commercial PVC grains and hexyl ethyl cellulose and lauroyl peroxide at a temperature of 60 °C, is reported. The addition of the graphene oxide (GO) sheets dispersed in dimethylformamide to the reaction mixture leads to the generation of composites made of PVC spheres coated with GO sheets. Scanning electron microscopy studies have demonstrated that this method allows for the transformation of PVC grains with sizes between 75 and 227 μm into spheres with sizes varying from 0.7 to 3.5 μm when the GO concentration in the PVC/GO composite mass increases from 0.5 to 5 wt.%. Our studies of Raman scattering and FTIR spectroscopy highlight a series of changes that indicate the appearance of ClCH=CH–, CH₂=CCl–, and/or –CH=CCl– units as a result of PVC partial dehydrogenation. New –COO– and C–OH bonds on the GO sheet surfaces are induced during the preparation of PVC spheres coated with GO sheets. A photoluminescence (PL) band with a maximum at 325 nm is reported to characterize the PVC spheres. A PVC PL quenching process is demonstrated to be induced by the increase in the concentration of the GO sheets in the PVC/GO composite mass. The perspectives regarding the use of this composite as a flame-retardant material are also reported. Full article

(This article belongs to the Special Issue Polymers and Nanomaterials: Interactions and Applications)

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28 pages, 6575 KiB

Open AccessArticle

Variations in Wettability and Interfacial Tension during Alkali–Polymer Application for High and Low TAN Oils

by Vladislav Arekhov, Rafael E. Hincapie, Torsten Clemens and Muhammad Tahir

Polymers 2020, 12(10), 2241; https://doi.org/10.3390/polym12102241 - 29 Sep 2020

Cited by 11 | Viewed by 2249

Abstract

The injection of chemicals into sandstones can lead to alterations in wettability, where oil characteristics such as the TAN (total acid number) may determine the wetting state of the reservoir. By combining the spontaneous imbibition principle and the evaluation of interfacial tension index, [...] Read more.

The injection of chemicals into sandstones can lead to alterations in wettability, where oil characteristics such as the TAN (total acid number) may determine the wetting state of the reservoir. By combining the spontaneous imbibition principle and the evaluation of interfacial tension index, we propose a workflow and comprehensive assessment to evaluate the wettability alteration and interfacial tension (IFT) when injecting chemical-enhanced oil-recovery (EOR) agents. This study examines the effects on wettability alteration due to the application of alkaline and polymer solutions (separately) and the combined alkali–polymer solution. The evaluation focused on comparing the effects of chemical agent injections on wettability and IFT due to core aging (non-aged, water-wet and aged, and neutral to oil-wet), brine composition (mono vs. divalent ions); core mineralogy (~2.5% and ~10% clay), and crude oil type (low and high TAN). Amott experiments were performed on cleaned water-wet core plugs as well as on samples with a restored oil-wet state. IFT experiments were compared for a duration of 300 min. Data were gathered from 48 Amott imbibition experiments with duplicates. The IFT and baselines were defined in each case for brine, polymer, and alkali for each set of experiments. When focusing on the TAN and aging effects, it was observed that in all cases, the early time production was slower and the final oil recovery was longer when compared to the values for non-aged core plugs. These data confirm the change in rock surface wettability towards a more oil-wet state after aging and reverse the wettability alteration due to chemical injections. Furthermore, the application of alkali with high TAN oil resulted in a low equilibrium IFT. By contrast, alkali alone failed to mobilize trapped low TAN oil but caused wettability alteration and a neutral–wet state of the aged core plugs. For the brine composition, the presence of divalent ions promoted water-wetness of the non-aged core plugs and oil-wetness of the aged core plugs. Divalent ions act as bridges between the mineral surface and polar compound of the in situ created surfactant, thereby accelerating wettability alteration. Finally, for mineralogy effects, the high clay content core plugs were shown to be more oil-wet even without aging. Following aging, a strongly oil-wet behavior was exhibited. The alkali–polymer is demonstrated to be efficient in the wettability alteration of oil-wet core plugs towards a water-wet state. Full article

(This article belongs to the Special Issue Polymers and Nanomaterials: Interactions and Applications)

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15 pages, 1929 KiB

Open AccessArticle

Strength of Flocs Formed by the Complexation of Lysozyme with Leonardite Humic Acid

by Wan Khairunnisa Wan Abdul Khodir, Azizul Hakim and Motoyoshi Kobayashi

Polymers 2020, 12(8), 1770; https://doi.org/10.3390/polym12081770 - 7 Aug 2020

Cited by 2 | Viewed by 2993

Abstract

Aggregation and aggregates properties of natural organic and nanosized macromolecules such as humic substances and proteins are crucial to explore so-called colloid-mediated transport and the fate of substances in soil and water environments. Therefore, the aggregation and dispersion, charging, and floc strength of [...] Read more.

Aggregation and aggregates properties of natural organic and nanosized macromolecules such as humic substances and proteins are crucial to explore so-called colloid-mediated transport and the fate of substances in soil and water environments. Therefore, the aggregation and dispersion, charging, and floc strength of lysozyme (LSZ)–leonardite humic acid (LHA) flocs were experimentally investigated. The experiments were performed in different salt concentrations and LSZ to LHA mass ratios as a function of pH. We obtained the stronger flocs at pH 4.4, where the isoelectric point (IEP) of the complex with the mass ratio 2.5 was confirmed. Thus, the aggregation of LSZ–LHA flocs is mainly caused by charge neutralization. We obtained the floc strength of 4.7 nN around IEP at low salt concentration of 3 mM, which was stronger than 2.8 nN in high salt concentration of 50 mM. The effect of salt concentration can be rationalized by charge-patch attraction at low salt concentration. With increasing mass ratio, the IEP shifted to higher pH. This is due to the increase in positive charge from LSZ in the mixture. The effect of the LSZ to LHA mass ratio on the maximum strength was weak in the range studied. Full article

(This article belongs to the Special Issue Polymers and Nanomaterials: Interactions and Applications)

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24 pages, 4918 KiB

Open AccessArticle

Micellization Behaviour of Linear and Nonlinear Block Copolymers Based on Poly(n-hexyl isocyanate) in Selective Solvents

by Aggelos Vazaios, Athanasios Touris, Mikel Echeverria, Georgia Zorba and Marinos Pitsikalis

Polymers 2020, 12(8), 1678; https://doi.org/10.3390/polym12081678 - 28 Jul 2020

Cited by 7 | Viewed by 2378

Abstract

Block copolymers have attracted significant scientific and economic interest over the last decades due to their ability to self-assemble into ordered structures both in bulk and in selective solvents. In this work, the self-assembly behaviour of both linear (diblocks, triblocks and pentablocks) and [...] Read more.

Block copolymers have attracted significant scientific and economic interest over the last decades due to their ability to self-assemble into ordered structures both in bulk and in selective solvents. In this work, the self-assembly behaviour of both linear (diblocks, triblocks and pentablocks) and nonlinear (miktoarm stars and a block-graft) copolymers based on poly(n-hexyl isocyanate), PHIC, were studied in selective solvents such as n-heptane and n-dodecane. A variety of experimental techniques, namely static and dynamic light scattering, dilute solution viscometry and atomic force microscopy, were employed to study the micellar structural parameters (e.g., aggregation number, overall micellar size and shape, and core and shell dimensions). The effect of the macromolecular architecture, the molecular weight and the copolymer composition on the self-assembly behaviour was studied. Spherical micelles in equilibrium with clusters were obtained from the block copolymers. Thermally stable, uniform and spherical aggregates were found from the triblock copolymers. The poly(n-hexyl isocyanate)-b-polyisoprene-b-poly(n-hexyl isocyanate),-HIH copolymers tend to adopt closed loop conformation, leading to more elongated cylindrical-type structures upon increasing the concentration. Clustering effects were also reported in the case of the pentablock terpolymers. The topology of the blocks plays an important role, since the poly(n-hexyl isocyanate)-b-polystyrene-b-polyisoprene-b-polystyrene-b-poly(n-hexyl isocyanate), HSISH terpolymer shows intermicellar fusion of spherical micelles, leading to the formation of extended networks. The formation of spherical micelles in equilibrium with clusters was obvious in the case of the miktoarm stars, whereas the block-graft copolymer shows the existence of mainly unimolecular micelles. Full article

(This article belongs to the Special Issue Polymers and Nanomaterials: Interactions and Applications)

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13 pages, 3377 KiB

Open AccessArticle

Hydrophilic Submicron Nanogel Particles for Specific Recombinant Proteins Extraction and Purification

by Gaëlle Levourch, Noureddine Lebaz and Abdelhamid Elaissari

Polymers 2020, 12(6), 1413; https://doi.org/10.3390/polym12061413 - 24 Jun 2020

Cited by 5 | Viewed by 2647

Abstract

In biomedical diagnosis and bionanotechnologies, the extraction and purification of proteins and protein derivatives are of great interest. In fact, to purify recombinant proteins for instance, new methodologies and well appropriate material supports need to be established and also to be evaluated. In [...] Read more.

In biomedical diagnosis and bionanotechnologies, the extraction and purification of proteins and protein derivatives are of great interest. In fact, to purify recombinant proteins for instance, new methodologies and well appropriate material supports need to be established and also to be evaluated. In this work, hydrophilic nanohydrogel particles were prepared for recombinant proteins extraction for purification purpose. The prepared nanohydrogel polymer-based particles are hydrophilic below the volume phase transition temperature (TVPT) and dehydrated above the TVPT, due to the thermally sensitive poly(N-alkyl acrylamide) and poly(N-alkyl methacrylamide) derivatives. Then, the use of heavy metal ions in the presence of such functional particles should specifically capture recombinant proteins (i.e., proteins bearing a poly(histidine) part). In order to understand and to optimize the specific capture and the purification of recombinant proteins, various parameters have been investigated as a systematic study. Firstly, the adsorption was investigated as a function of pH and protein concentration. According to high hydration of the prepared nanohydrogel, no marked adsorption was observed. Secondly, the effect of pH was investigated and found to be the driven parameter affecting the metal ions immobilization and the recombinant proteins complexation. As a result, high protein complexation was observed at basic pH compared to non-complexation at acidic pH medium. The immobilized proteins via complexation were released by changing the pH. This decomplexation seems to be effective but depends on fixation conditions and particle surface structure. Full article

(This article belongs to the Special Issue Polymers and Nanomaterials: Interactions and Applications)

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13 pages, 3925 KiB

Open AccessArticle

Direct Observation of Relaxation of Aqueous Shake-Gel Consisting of Silica Nanoparticles and Polyethylene Oxide

by Yi Huang and Motoyoshi Kobayashi

Polymers 2020, 12(5), 1141; https://doi.org/10.3390/polym12051141 - 16 May 2020

Cited by 15 | Viewed by 3515

Abstract

Controlling the rheological property of suspensions consisting of colloidal particles and polymers is necessary in industry. Especially, gels induced by shear (shake-gel) are interesting phenomena in rheological field. To gain insight into the shake-gel phenomena of the aqueous suspensions of silica nanoparticles and [...] Read more.

Controlling the rheological property of suspensions consisting of colloidal particles and polymers is necessary in industry. Especially, gels induced by shear (shake-gel) are interesting phenomena in rheological field. To gain insight into the shake-gel phenomena of the aqueous suspensions of silica nanoparticles and poly(ethylene oxide) (PEO) and its temporal change, we observed the state transition and measured the viscosity of the silica-PEO suspensions. Our results showed that PEO dose, pH, and molecular weight of PEO influence the state of suspension greatly, and revealed the differences of the suspension states, namely, cloudy, permanent gel, shake-gel, and high viscosity sol. We found that the relaxation time from shake-gel to flowable sol increases to the maximum and decreases again with increasing PEO dose. Shake-gels at pH 8.4 relaxed more slowly than at pH 9.4, and shake-gel did not form at pH above 10 in most of cases, indicating high pH inhibits the formation of shake-gels. PEO of molecular weight of 1000 and 4000 kDa easily bonds more silica nanoparticles by bridging and results in the formation of gels with more stable polymer networks. PEO of molecular weight of 1000 and 4000 kDa also led to longer relaxation time of the silica-PEO suspensions from gel to sol. Full article

(This article belongs to the Special Issue Polymers and Nanomaterials: Interactions and Applications)

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16 pages, 3384 KiB

Open AccessArticle

Removal of Lindane from Aqueous Solution Using Aluminum Hydroxide Nanoparticles with Surface Modification by Anionic Surfactant

by Thi Hang Nguyen, Thi Thuy Linh Nguyen, Tien Duc Pham and Thanh Son Le

Polymers 2020, 12(4), 960; https://doi.org/10.3390/polym12040960 - 20 Apr 2020

Cited by 19 | Viewed by 4075

Abstract

In the present study, we investigated the removal of an emerging pesticide lindane from aqueous solution using synthesized aluminum hydroxide Al(OH)₃ (bayerite) nanomaterials with surface modification by an anionic surfactant sodium dodecyl sulfate (SDS). The Al(OH)₃ nanoparticles were characterized by X-ray [...] Read more.

In the present study, we investigated the removal of an emerging pesticide lindane from aqueous solution using synthesized aluminum hydroxide Al(OH)₃ (bayerite) nanomaterials with surface modification by an anionic surfactant sodium dodecyl sulfate (SDS). The Al(OH)₃ nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) and zeta potential. The lindane removal using SDS-modified nano-aluminum hydroxide nanoparticles (SMNAH) achieved removal of up to 93.68%, which was 3.3 times higher than that of nano-aluminum hydroxide nanoparticles. The adsorptive removal conditions were studied and found to have an adsorption time of 60 min, a pH of 6, an adsorbent dosage of 25 mg/mL and an ionic strength of 10 mM NaCl. After reusing four times, the removal efficiency of lindane using SMNAH still reached 75%. Two-step adsorption can fit adsorption isotherms of lindane onto SMNAH at two salt concentrations. On the basis of the change in zeta potential, surface functional groups and adsorption isotherms, we suggest that the formation of a bilayer micelle induced the removal of lindane. Full article

(This article belongs to the Special Issue Polymers and Nanomaterials: Interactions and Applications)

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16 pages, 2970 KiB

Open AccessEditor’s ChoiceArticle

Self-Consistent Mean Field Calculations of Polyelectrolyte-Surfactant Mixtures in Solution and upon Adsorption onto Negatively Charged Surfaces

by Eduardo Guzmán, Laura Fernández-Peña, Gustavo S. Luengo, Ana María Rubio, Antonio Rey and Fabien Léonforte

Polymers 2020, 12(3), 624; https://doi.org/10.3390/polym12030624 - 9 Mar 2020

Cited by 25 | Viewed by 3581

Abstract

Self-Consistent Mean-Field Calculations (SCF) have provided a semi-quantitative description of the physico-chemical behavior of six different polyelectrolyte-surfactant mixtures. The SCF calculations performed showed that both the formation of polymer-surfactant in bulk and the adsorption of the formed complexes onto negatively-charged surfaces are strongly [...] Read more.

Self-Consistent Mean-Field Calculations (SCF) have provided a semi-quantitative description of the physico-chemical behavior of six different polyelectrolyte-surfactant mixtures. The SCF calculations performed showed that both the formation of polymer-surfactant in bulk and the adsorption of the formed complexes onto negatively-charged surfaces are strongly affected by the specific nature of the considered systems, with the polymer-surfactant interactions playing a central role in the self-assembly of the complexes that, in turn, affects their adsorption onto interfaces and surfaces. This work evidences that SCF calculations are a valuable tool for deepening on the understanding of the complex physico-chemical behavior of polyelectrolyte-surfactant mixtures. However, it is worth noting that the framework obtained on the basis of an SCF approach considered an equilibrium situation which may, in some cases, be far from the real situation appearing in polyelectrolyte-surfactant systems. Full article

(This article belongs to the Special Issue Polymers and Nanomaterials: Interactions and Applications)

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Review

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30 pages, 4216 KiB

Open AccessReview

Chemical Sand Consolidation: From Polymers to Nanoparticles

by Fahd Saeed Alakbari, Mysara Eissa Mohyaldinn, Ali Samer Muhsan, Nurul Hasan and Tarek Ganat

Polymers 2020, 12(5), 1069; https://doi.org/10.3390/polym12051069 - 7 May 2020

Cited by 45 | Viewed by 9176

Abstract

The chemical sand consolidation methods involve pumping of chemical materials, like furan resin and silicate non-polymer materials into unconsolidated sandstone formations, in order to minimize sand production with the fluids produced from the hydrocarbon reservoirs. The injected chemical material, predominantly polymer, bonds sand [...] Read more.

The chemical sand consolidation methods involve pumping of chemical materials, like furan resin and silicate non-polymer materials into unconsolidated sandstone formations, in order to minimize sand production with the fluids produced from the hydrocarbon reservoirs. The injected chemical material, predominantly polymer, bonds sand grains together, lead to higher compressive strength of the rock. Hence, less amounts of sand particles are entrained in the produced fluids. However, the effect of this bonding may impose a negative impact on the formation productivity due to the reduction in rock permeability. Therefore, it is always essential to select a chemical material that can provide the highest possible compressive strength with minimum permeability reduction. This review article discusses the chemical materials used for sand consolidation and presents an in-depth evaluation between these materials to serve as a screening tool that can assist in the selection of chemical sand consolidation material, which in turn, helps optimize the sand control performance. The review paper also highlights the progressive improvement in chemical sand consolidation methods, from using different types of polymers to nanoparticles utilization, as well as track the impact of the improvement in sand consolidation efficiency and production performance. Based on this review, the nanoparticle-related martials are highly recommended to be applied as sand consolidation agents, due to their ability to generate acceptable rock strength with insignificant reduction in rock permeability. Full article

(This article belongs to the Special Issue Polymers and Nanomaterials: Interactions and Applications)

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