Copolymer Solutions Research Articles

Preparation of thickened P(AA-AMPS) copolymers by inverse emulsion polymerization and evaluation of fracturing and oil flooding performance

Polymer is an essential type of fracturing fluid. Nevertheless, issues such as slow dissolution, high initial viscosity, and challenges in storage, transportation and operation limit its application. To address these issues, a thickened copolymer P(AA-AMPS) was synthesized by inverse emulsion polymerization using acrylic acid (AA) and 2-acrylamide-2-methylpropanesulfonic acid (AMPS) as the monomers. Three P(AA-AMPS) copolymers were obtained by changing the weight ratio of AA and AMPS monomers. When the weight ratio of AA to AMPS monomers was 8.2:1.8, the P(AA-AMPS) copolymer solution exhibited the best interfacial activity, reducing the oil–water interfacial tension to 3.95 mN m−1. The initial viscosity of the copolymer was only 66 mPa s, but its solution could reach a high viscosity of up to 817 mPa s. P(AA-AMPS) copolymers demonstrated good resistance for temperature and shear. For instance, the viscosity of copolymer solution still remained 300 mPa s with a shear rate of 170 s−1 at 90 °C. Furthermore, P(AA-AMPS) copolymers had excellent gel-breaking capacity, sand suspension stability, wettability and oil displacement ability. Therefore, the integration of fracturing and oil flooding can be realized for the development of low permeability reservoirs by selecting appropriate copolymers. P(AA-AMPS) copolymers would play an important role due to their significant viscosity differences and easy operation on storage, transportation and application.

Dynamic Surface Properties of Styrene and Hydrophobized 4-Vinylbenzyl Chloride Copolymers at the Air-Water Interface

The kinetic dependences of surface tension, dilatational dynamic surface elasticity and ellipsometric angles of solutions of copolymers of styrene and 4-vinylbenzyl chloride modified with N,N-dimethyldodecylamine, as well as the micromophology of adsorption and spread layers of this polyelectrolyte were determined. All kinetic dependences of the dynamic surface elasticity were found to be monotonic, in contrast to the results for previously studied polyelectrolyte solutions without polystyrene fragments. The peculiarities of surface properties of the studied solutions may be related to the formation of microaggregates in the surface layer, preventing the formation of loops and tails of polymer chains at the interfacial boundary, and, consequently, the decrease in surface elasticity after the local maximum. The occurrence of aggregates with sizes of 1–4 nm in the Z-direction in the surface layer is also indicated by atomic force microscopy data. The obtained results confirm the earlier conclusions about the formation of aggregates in the surface layer of polyelectrolyte solutions containing sodium polystyrene sulfonate (PSS) fragments. A two-dimensional phase transition to a denser surface phase at surface pressures of 25–30 mN/m and the formation of aggregates with a size of 40 nm in the Z-direction were found for applied polyelectrolyte layers without styrene monomers on an aqueous substrate.

Achieving antibiofouling on microporous membranes prepared with a green solvent via spraying an aqueous antifouling copolymer solution

This study highlights a comprehensive investigation into the fabrication and characterization of sustainable membranes for antifouling applications. It utilizes γ-valerolactone as a green solvent to obtain microfiltration polyvinylidene difluoride (PVDF) membranes, and leverages spray-coating technique to modify these membranes. This research aims to enhance the surface and bulk properties of PVDF membranes while promoting sustainable practices. Chemical analyses of the membranes reveal that the surface and bulk of the membranes were successfully modified. Dynamic water contact angle measurements indicated that a 10 mg/mL coating solution (PVDF_10) resulted in the highest hydrophilicity. Different biofouling tests were conducted using proteins and bacteria. In adhesion tests with BSA, and E. coli, the PVDF_10 membrane demonstrated the highest resistance, reducing adhesion by approximately 83 % and 94 %, respectively. Additionally, cyclical water/bacterial filtration tests demonstrated that PVDF_10 membrane achieved a higher flux recovery ratio compared to commercial hydrophilic PVDF membranes. The modification remained stable even after 6 weeks of immersion in water. This study highlights the potential of γ-GVL and the spray-coating technique as environmentally friendly solvents and modification techniques for producing green antifouling PVDF membranes, aligning with sustainable practices and significantly enhancing membrane performance.

The advancement of EVA polymerization kinetics and development of high-performance EVOH polymerization process

Ethylene-vinyl alcohol copolymer (EVOH) is a material with excellent barrier properties, produced via the radical copolymerization of ethylene and vinyl acetate in solution, followed by alcoholysis in methanol with NaOH as a catalyst. It is widely used in packaging and medical materials. However, balancing the barrier properties and processability remains challenging. Currently, multi-scale research methods using density functional theory (DFT) to explore polymerization mechanisms and obtain kinetic data, combined with process simulation methods to develop high-performance EVOH polymerization process, are gaining attention. Therefore, this study employs DFT and transition state theory (TST) methods to study the kinetics of chain growth and chain transfer reactions of radicals at first, yielding the average chain growth and chain transfer rate constants for copolymerization reactions. Then, based on these rate constants, process simulations were used to model the ethylene–vinyl acetate solution copolymerization reactor, developing polymerization process for EVOH with high barrier properties as well as EVOH with both high barrier properties and good processability. These findings provide suggestions and guidance for EVOH production and application.

A Computer Simulation Study on Deposition Patterns of Cyclic Diblock Copolymer Solution Nanodroplets: Influence of Polymer Length and Concentration

A Computer Simulation Study on Deposition Patterns of Cyclic Diblock Copolymer Solution Nanodroplets: Influence of Polymer Length and Concentration

Effect of ionic bonding on luminescence properties of histidine maleic anhydride derivatives

Polymeric materials exhibiting room-temperature phosphorescent (RTP) have attracted wide attention for their easy synthesis, low toxicity, and applications in various fields such as data encryption, cell imaging, information security and other fields. Nevertheless, the conventional ways of preparing such materials are mainly focused on doping, which may suffer from phase separation, poor compatibility, and lack of effective methods to promote intersystem crossing and suppress the nonradiative deactivation rates. Herein, a series of polymers with fluorescence and phosphorescence dual emission were prepared by simple radical solution copolymerization. Through rigid ion-bonded cross-linked networks and cross-linked hydrogen-bonded networks between the polymer chains, the non-radiative jumps and achieve ultra-long phosphorescence lifetimes were able to suppress. By suppressing non-radiative transitions through rigid ion-bonded cross-linked networks and intermolecular hydrogen-bonding networks between polymer chains, ultra-long phosphorescence is achieved. Impressively, a LRTP lifetime of up to 815.38 ms in polymers under ambientconditions is set up. Moreover, in this study, phosphorescence emission can be easily tuned by balancing ion radius and charge states. These results outline the construction of polymeric materials, endowing traditional polymers with new characteristics and promising potential applications.

Visualization study on the dry devolatilization characteristics of styrene-butadiene-styrene block copolymers

Dry devolatilization is a promising method for saving energy, but understanding the devolatilization process has been challenging. A static devolatilizer was designed to study the devolatilization process of a Styrene-butadiene-styrene (SBS) block copolymer solution at different temperatures using visualization technology. The study found that temperature, Reynolds number, and heat flux are key factors influencing the devolatilization process. The optimal residence time was determined to be 196 s and the suitable feed coefficient is 0.17. Additionally, a new dimensionless parameter (the LZ number) was introduced. A value closer to 1 indicated a more effective devolatilization process. The obtained thermodynamic parameters and LZ number can guide the design of industrial devolatilization devices.

Engineering Thermoresponsive Poly(N-isopropylacrylamide)-Based Films with Enhanced Stability and Reusability for Efficient Bone Marrow Mesenchymal Stem Cell Culture and Harvesting.

Poly(N-isopropylacrylamide) (PNIPAM) offers a promising platform for non-invasive and gentle cell detachment. However, conventional PNIPAM-based substrates often suffer from limitations including limited stability and reduced reusability, which hinder their widespread adoption in biomedical applications. In this study, PNIPAM copolymer films were formed on the surfaces of glass slides or silicon wafers using a two-step film-forming method involving coating and grafting. Subsequently, a comprehensive analysis of the films' surface wettability, topography, and thickness was conducted using a variety of techniques, including contact angle analysis, atomic force microscopy (AFM), and ellipsometric measurements. Bone marrow mesenchymal stem cells (BMMSCs) were then seeded onto PNIPAM copolymer films prepared from different copolymer solution concentrations, ranging from 0.2 to 10 mg·mL-1, to select the optimal culture substrate that allowed for good cell growth at 37 °C and effective cell detachment through temperature reduction. Furthermore, the stability and reusability of the optimal copolymer films were assessed. Finally, AFM and X-ray photoelectron spectroscopy (XPS) were employed to examine the surface morphology and elemental composition of the copolymer films after two rounds of BMMSC adhesion and detachment. The findings revealed that the surface properties and overall characteristics of PNIPAM copolymer films varied significantly with the solution concentration. Based on the selection criteria, the copolymer films derived from 1 mg·mL-1 solution were identified as the optimal culture substrates for BMMSCs. After two rounds of cellular adhesion and detachment, some proteins remained on the film surfaces, acting as a foundation for subsequent cellular re-adhesion and growth, thereby implicitly corroborating the practicability and reusability of the copolymer films. This study not only introduces a stable and efficient platform for stem cell culture and harvesting but also represents a significant advance in the fabrication of smart materials tailored for biomedical applications.

Synthesis and performance study of biomass-based suppressant and its application in radioactive aerosol sedimentation

The decommissioning of nuclear facilities and nuclear accidents may release a various amount of radioactive aerosols, which could pose a serious threat to the natural environment and human health. Therefore, there is a need to develop an eco-friendly aerosol suppressant to control the radioactive aerosol. In this paper, carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), rhamnolipid and sophorajaponica glycolipid were selected as the raw material, and the aerosol suppressant was prepared by solution polymerization. The sample was characterized by FTIR, TGA, viscosity, surface tension and contact angle analysis. The results indicated that the grafted reaction was successful. Rhamnolipid and sophorajaponica glycolipid effectively reduced the surface tension of the copolymer solution to 27.7 mN/m, and the contact angle between the polymer solution and experimental dust was decreased to 27.36°. The aerosol sedimentation experiment showed that the suppressant had a significant effect on aerosol. The sedimentation efficiency of concrete aerosols was 87.7%, and the sedimentation efficiency of radioactive aerosols reached 90.8%. It provided an eco-friendly and effective method to quickly and easily control and remove high-concentration radioactive aerosol.

Hydrodynamic Properties and LCST Behavior of Six-Armed Star-Shaped Polymers with Arms of a Diblock Copolymer of Poly-2-Ethyl-2-Oxazine and Poly-2-Isopropyl-2-Oxazine

Star-shaped six-arm polymers with arms of the block copolymers of poly-2-ethyl-2-oxazine and poly-2-isopropyl-2-oxazine were synthesized. The branching center was hexaase[26]cyclophane. The prepared samples differed in the order of block attachment to the core. Molar masses of the two samples were 14200 and 21500 g⋅mol−1. The fractions of poly-2-ethyl-2-oxazine monomers in the arms were 61 and 65%, respectively. It was shown that the arms were strongly folded. Water-salt solutions of the star-shaped block copolymers exhibited thermoresponsiveness. The difference in the phase separation temperatures for the studied samples was caused by the differences in their molar masses and the different contents of poly-2-ethyl- and poly-2-isopropyl-2-oxazine blocks. The concentration dependences of the phase separation temperatures for the synthesized star-shaped copolymers coincided with those for the arms, despite the fact that the molecular masses of the stars and their arms differed by factor of near 6. The addition of NaCl to the aqueous of solutions of the star copolymers did not lead to significant changes in their characteristics. No influence of the order of the block attachment to the core on the molecule conformation and on the thermoresponsive behavior was found.

Pronounced Cold Crystallization and Hydrogen Bonding Distortion of Water Confined in Microphases of Double Zwitterionic Block Copolymer Aqueous Solutions.

Advanced materials leveraging water control are garnering considerable interest, with the state of water emerging as a critical aspect of material design. This study explored the impact of microphase separation on water using aqueous solutions of double zwitterionic diblock copolymers, specifically poly(carboxybetaine methacrylate) and poly(sulfobetaine methacrylate) (PCB2-b-PSB4). These copolymers form a mesoscale periodic ordered lattice structure consisting of two distinct aqueous phases. Through differential scanning calorimetry and X-ray emission spectroscopy, it was found that water in these PCB2-b-PSB4 aqueous solutions exhibits pronounced cold crystallization and subtle distortions in hydrogen-bonding configurations.

A green bulk modification for imparting a green VIPS membrane with antifouling properties

BackgroundMembrane preparation and membrane modification processes have long involved the use of toxic solvents. The present work proposes to only use envrionmentally-friendly solvents for both the fabrication and the surface modification of hydrophobic microfiltration membranes. In addition, coating processes for membrane modification are essentially surface modification processes. However, spray-coating may be a suitable method for both surface and bulk modification. MethodsAfter dissolving poly(vinylidene fluoride) in dimethylsulfoxide, membranes were formed by the vapor-induced phase separation process, and then modified using an aqeous solution of an amphiphilic copolymer containing poly(ethylene glycol) methyl ether methacrylate units. Then, a variety of physicochemical techniques were employed to characterize the membrane structure and prove the effectiveness of the surface/bulk modification. Antifouling tests in static and dynamic conditions were conducted. Significant findingsIt is possible to reduce the water contact angle of the top surface of the membrane from 135° to 0° and that of the bottom surface from 126° to 0° within <10 s, indicating successful hydrophilization of the membrane on the one hand, and top-to-bottom modification, despite solely exposing the top surface to the spray, on the other hand. This conclusion was confirmed by deidcated surface chemistry analyses. Besides, the membranes maintained their original highly porous and symmetric structure with light effects on surface porosity and pore size following the spray-coating process. The drasting improvement of hydrophilicity resulted in effective mitigation of fibrinogen adsorption (reduced by 85 %) and Escherichia coli adhesion (reduced by 86 %). Fouling during cyclic filtration involving a bacterial suspension was also effectively reduced with a flux recovery ratio of 53 % (against 37 % for a commercial hydrophilic membrane) and an irreversible flux decline ratio of 47 % (against 63 % for a commercial hydrophilic membrane) in the conditions of the test.

Leveraging an innovative process integration using highly acid-immune blend membranes for enhanced acid recovery and selective salt separation

We investigate the efficiency and advantage of the integrated diffusion dialysis-electrodialysis (DD-ED) system over the DD process for acid recovery with highly acidic wastewater. The investigation uses various acid (HCl/H2SO4) /salt mixtures encompassing iron, copper and aluminium salts (FeCl2, CuCl2, AlCl3, and FeSO4) as simulated feed. The membrane is prepared using blend mixture of polyvinylidene fluoride (PVDF) and polymethyl methacrylate-co-poly chloromethyl styrene copolymer (PMMA-co-PCMSt) solution by non-solvent induced phase inversion on a nonwoven fabric followed by treatment with different tertiary amines. Representative AEM-Q3 membrane prepared by the post modification of blend membrane with a mixture of N, N, N’, N’- tetramethyl diamino hexane (TMDAH) and trimethyl amine (TMA) (1: 1 w/w %) exhibited the best-balanced performance. The membrane recovered a 84.2% AR (%) of acid with 96.28% purity (%) at a flux (JH+) of 7.08 × 10-4 mol cm-2 h-1 from 3 M HCl and 0.2M FeCl2 mixture making it suitable for further studies. A comprehensive comparative study drawn between the DD and integrated DD-ED showed that there was a 2.3 fold increment in acid recovery for the integrated process over the DD process (for the HCl-FeCl2 system). The membranes have also shown good monovalent (Cl-) and bivalent (SO42-) anion selectivity of 7.8. However, the selectivity was further improved to 12.28 by modification of AEM-Q3 membrane, which is double side cast (referred as AEM-Q3/b). The synthetic strategy of the membrane is easy and scalable and has potential for both acid recovery and selective salt separation by ED process.

Effect of ionic liquids on the polymerization behavior of acrylamide‐based copolymers

AbstractTo explore the influence of reaction medium on the copolymerization behavior of acrylamide‐based copolymers, three types of copolymers (P(AM‐St)(ILs), P(AM‐MMA)(ILs), and P(AM‐AMPS)(ILs)) were synthesized by combining insoluble, slightly soluble, and easily soluble monomers with acrylamide in the 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([BMIM]BF4) reaction medium. The reactivity ratio, Fourier transform infrared spectroscopy, 1H NMR spectroscopy, elemental analysis, and scanning electron microscopy were employed to characterize the copolymers' properties. The results indicated that in [BMIM]BF4 copolymerization, the reactivity ratio of AM and St in P(AM‐St)(ILs) decreased, the reactivity ratio of AM in P(AM‐MMA)(ILs) will increase. While the reactivity ratio of MMA will decrease. The reactivity ratio of AM in P(AM‐AMPS)(ILs) will increase and the reactivity ratio of AMPS will decrease. The distribution of AM and St segments in P(AM‐St)(ILs) molecular chains is more uniform and compact. When AM polymerizes with hydrophobic monomers (St) in [BMIM]BF4, its copolymer solution exhibits lower viscosity loss rates in temperature, shear, and salt resistance tests. Therefore, ionic liquids are more suitable as reaction media for the synthesis of hydrophobic‐modified polyacrylamides, which facilitate a more uniform distribution of hydrophobic monomers within the copolymer chains and exhibit enhanced resistance to temperature, salt, and shear stresses.

Efficient synthesis of the cyclo-olefin copolymers at high temperature and pressure in a homogeneous mini-tubular reactor

Ethylene-norbornene copolymer (ENC) is one of the most representative cyclo-olefin copolymer (COC). Both the amorphous and semi-crystalline ENCs were efficiently synthesized by the homogeneous solution copolymerization of ethylene (E) and norbornene (NB) using rac-Et(Ind)2ZrCl2/triisobutylaluminium/(Ph3C)B(C6F5)4 ternary catalyst system in a visualized mini-tubular reactor under high temperature (90–130 °C) and given pressure (24 bar). An ultra-high activity of 7.6 × 108 g/(molZr h), as well as considerable efficiency of 14.1 kgENC/gZr was achieved in time of only 30 s at E/NB molar ratio of 3:1. Moreover, a quench-labeling method using 2-thiophenecarbonyl chloride (TPCC) was adopted to calculate the high proportion of active center [C*]/[Zr]. The novel strategy was proposed for preparation of the block semi-crystalline ENC elastomers with excellent tensile performance and high transparency via reversible chain transfer based on spatiotemporal concentration distribution in a mini-tubular reactor.

Enhancing biofilm resistance and preserving optical translucency of 3D printed clear aligners through carboxybetaine-copolymer surface treatment

ObjectivesThis study aimed to use a carboxybetaine methacrylate (CBMA) copolymer solution to surface treat 3D printed clear aligners at different fabrication stages, to impart antifouling properties, and assess the surface treatment at various fabrication stages' impact on physico-mechanical characteristics. MethodsSurface treatments using a blend of 2-hydroxyethyl methacrylate (HEMA) and CBMA, termed CCS, were performed at various stages of 3D printed clear aligner fabrication. Experimental groups, CB1, CB2, and CB3, were determined by the stage of surface treatment during post-processing. CB1, CB2, and CB3 received treatment before post-curing, after post-curing, and after post-processing, respectively. Untreated samples served as controls. Physical and mechanical properties were assessed through tensile testing, Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and UV-Vis spectroscopy. The surface was further characterized through scanning electron microscopy and contact angle measurements. The cytotoxicity was assessed with 7-day elution and agar diffusion assays. Lastly, bacterial biofilm resistance was evaluated using confocal laser scanning microscopy. Crystal violet assay was performed using Streptococcus mutans. ResultsSurface treatment during CB1 stage exerted the most significantly unfavorable influence on properties of the 3D printed aligner resin. CB2 samples showed the maximum preservation of translucency even after 7-day aging. CB2 and CB3 phases showed enhanced hydrophilicity of sample surfaces with reduced adhesion of multispecies biofilm and S. mutans. SignificanceApplication of CCS surface treatment immediately after post-curing (CB2) can enhance the biofilm resistance of 3D printed clear aligners while maintaining high fidelity to optical translucency and constituent mechanical properties.

Deposition patterns formed by the evaporation of linear diblock copolymer solution nanodroplets on solid surfaces.

The evaporation-induced deposition pattern of the linear diblock copolymer solution has attracted attention in recent years. Given its critical applications, we study deposition patterns of the linear diblock copolymer solution nanodroplet on a solid surface (the wall) by molecular dynamics simulations. This study focuses on the influence of the nonbonded interaction strength, including the interaction between the wall and polymer blocks (ɛAW and ɛBW), the interaction between the solvent and the wall (ɛSW), and the interaction between polymer blocks (ɛAB). Conditions leading to diverse deposition patterns are explored, including the coffee-ring and the volcano-like structures. The formation of the coffee-ring structure is attributed to receding interfaces, the heterogeneity inside the droplet, and the self-assembly of polymer chains. This study contributes to the establishment of guidelines for designing deposition patterns of the linear diblock copolymer solution nanodroplet, which facilitates practical applications such as inkjet printing.

Exploring the impact of cresols on aggregation characteristics of non-linear PEO-PPO-PEO block copolymers in aqueous solution

The present research investigates the intricate interplay between some industrially essential compounds, viz. 2-methylphenol (o-cresol, OC), 4-methylphenol (p-cresol, PC), 4-n-Butylphenol (BP) and non-linear ethylene oxide-propylene oxide (EO-PO) type block copolymers (Tetronics®) in aqueous solutions by employing an array of physico-chemical techniques. Each examined Tetronic® possesses 40% EO segments in its molecular structure. The study delves into the interaction and structural modifications that occur when cresols are doped into the copolymer solutions. The added cresols disrupt the hydrophilic-hydrophobic balance of Tetronics® depending on their hydrophobicities. The lowering of the cloud point (CP) is accompanied by a corresponding increase in solution viscosity. Doping of OC and PC has a dissimilar effect on viscosity compared to BP. The intermicellar interactions are adjudged to be probable cause of the unusual viscosity trend. Scattering techniques (DLS and SANS) confirm the morphology of aggregates. The results are interpreted in terms of H-bonding.

Analysis of Phase Transitions of Thermoresponsive Polymer Based on N-Vinylcaprolactam and 2-Hydroxyethyl Acrylate in Solutions from the Information Theory Point of View

A new method for analyzing phase transitions in solutions of thermoresponsive polymers is proposed, based on determining the amount of information contained in the curve describing the phase transition. The method is based on the use of an analogy with the Nyquist-Shannon-Kotelnikov theorem, which allows us to bring the analysis of a continuous function to the analysis of its values at discrete points, as well as the results of studies of slowly changing signals from the point of view of modern information theory. This analogy allows us to determine the minimum number of parameters that describe the phase transition. The proposed method was tested using the example of phase transitions in solutions of thermoresponsive copolymers of N-vinylcaprolactam with 2-hydroxyethyl acrylate of various compositions. The effectiveness of this method has been demonstrated; in particular, it has been shown that the number of parameters that describe the phase transition in this case does not exceed four. The possibilities of using the proposed method for constructing a classification of phase transitions in solutions of stimulus-sensitive polymers are discussed.

Single laser synthesis of gold nanoparticles-polypyrrole-chitosan on laser-induced graphene for ascorbic acid detection

The simultaneous synthesis of gold nanoparticles (AuNPs) and graphene by laser ablation was demonstrated. The in-situ synthesis was performed by laser ablation of a polymer substrate covered with a gold precursor dispersion. The gold precursor was prepared in a copolymer solution of pyrrole (Py) and chitosan (Chi) to improve the nucleation of gold embedded on the laser-induced graphene electrode (LIGE). The morphology of AuNPs-pPy-Chi/LIGE was studied by scanning electron microscopy and characterized electrochemically by cyclic voltammetry. A comprehensive investigation of the electrochemical and physical features of the AuNPs-pPy-Chi/LIGE was carried out. The parameters of differential pulse voltammetry were adjusted to enhance the response to ascorbic acid (AA). The AuNPs-pPy-Chi/LIGE produced two linear ranges: from 0.25 to 5.00 and 5.00–25.00 mmol L−1. The limit of detection was 0.22 mmol L−1. Hundreds of electrodes were tested to demonstrate the excellent reproducibility of the AuNPs-pPy-Chi/LIGE fabrication. Overall, the proposed electrode allows the successful detection of AA in orange juice products with acceptable accuracy (recoveries = 97 ± 2 to 109.1 ± 0.7). The preparation strategy of the proposed AuNPs-pPy-Chi/LIGE could be adapted to detect other compounds or biomarkers.