Water-soluble Polymers Research Articles

Hydrophobically Associating Polyacrylamide “Water-in-Water” Emulsion Prepared by Aqueous Dispersion Polymerization: Synthesis, Characterization and Rheological Behavior

The hydrophobically associating polyacrylamide (HAPAM) is an important kind of water-soluble polymer, which is widely used as a rheology modifier in many fields. However, HAPAM products prepared in a traditional method show disadvantages including poor water solubility and the need for hydrocarbon solvents and appropriate surfactants, which lead to environmental pollution and increased costs. To solve these problems, we reported a novel kind of HAPAM "water-in-water" (w/w) emulsion and its solution properties. In this work, a series of cationic hydrophobic monomers with different alkyl chain lengths were synthesized and characterized. Then, HAPAM w/w emulsions were prepared by the aqueous dispersion polymerization of acrylamide, 2-methylacryloylxyethyl trimethyl ammonium chloride and a hydrophobic monomer. All these emulsions can be stored more than 6 months, showing excellent stability. An optical microscopy observation showed that the particle morphology and the particle size of the HAPAM emulsion were more regular and bigger than the emulsion without the hydrophobic monomer. The solubility tests showed that such HAPAM w/w emulsions have excellent solubility, which took no more than 180 s to dilute and achieve a homogeneous and clear solution. The rheology measurements showed that the HAPAM association increases with a hydrophobe concentration or the length of hydrophobic alkyl chains, resulting in better shear and temperature resistances. The total reduced viscosity was 124.42 mPa·s for cw101, 69.81 mPa·s for cw6-1, 55.38 mPa·s for cw8-0.25, 48.95 mPa·s for cw12-0.25 and 28 mPa·s for cw16-0.25 when the temperature increased from 30 °C to 90 °C. The cw8-2.0 that contains a 2 mol% hydrophobe monomer has the lowest value at 19.12 mPa·s due to the best association. Based on the excellent stability, solubility and rheological properties, we believe that these HAPAM w/w emulsions could find widespread applications.

Development of Seed-type Radiopharmaceuticals Based on In Vivo Aggregation of Water-soluble Polymer for Cancer-targeted Radiotherapy

近年，α線放出核種を利用したがん治療において，進行がんに対する高い治療効果が報告されたことより，核医学治療が再び脚光を浴びると同時に，これに資する薬剤開発に高い関心が集まっている。著者は，水溶性ポリマーであるポリオキサゾリン（POZ）が熱に応答して凝集する特徴を有する点に着目し，POZの生体内凝集効果に基づく小線源型放射性薬剤の開発を進めてきた。本稿では，これらの研究成果について紹介する。

К ВОПРОСУ РАЗРАБОТКИ ОТЕЧЕСТВЕННЫХ РЕСТАВРАЦИОННЫХ МАТЕРИАЛОВ ДЛЯ ПАМЯТНИКОВ АРХИТЕКТУРЫ

The article provides an overview of research on the specifics of the use and composition of restoration materials and solutions at different stages of the work. The need is shown for the development of domestic restoration materials that improve the quality of restoration, the long-term preservation of the restored object during operation and provide the possibility of choice in relation to each restoration task. The literature review gives the stages of restoration work of architectural monuments are given, the specifics of which depend on the use of functional additives in various repair mixtures. The review of research on the subject is focused on the importance of solving the problems of replacing imported modifier additives with domestic ones. The authors emphasize that the choice of additives of various functional purposes in prescription formulations should be made considering the compatibility patterns of the components of the materials being restored (including in the form of dry restoration mixtures), have a scientific integrated approach. The analysis of scientific achievements and publications where the solution of this problem has been initiated has shown that there are particular unresolved issues of the general problem to which this article is devoted. Polymer additives of domestic production of various chemical nature used in compositions based on mineral binders are given. Based on the analysis of physico-mechanical, rheotechnological and technological properties of compositions based on mineral binders, the possibility and advantage of using Russian water-soluble polymers in the compositions of restoration materials, taking into account the small dosage and environmental friendliness of these additives, is proved. Previous comparative analysis of conducted studies shows that increasing the range of modifying additives using Russian-made polymers and the production of competitively capable dry building mixes based on them for restoration operations will help to fulfill the task of preserving architectural objects of historical construction that reflect different epochs, an element of national culture and identity, ensuring the continuity of cultures.

The problem of high water cut in the products of horizontal wells

Background. The production of oil and gas by horizontal wells, despite all its advantages, is subject to exploratory and operational complications. At the final stage of their development, such fields become hard-to-recover reserves. Production of oil and gas is often associated with a high water cut, a significant drop in reservoir pressure, and precipitation of asphaltene deposits.Aim. To analyze the problem of early indication of flooding of horizontal wells and do research on existing solutions nowadays.Materials and methods. The dependence of the logarithm of the water-oil ratio on the cumulative oil production was investigated. An analysis of production decline curves was carried out, along with a graphical diagnostics of flooding evolution.Results. The anticipated cumulative production of a well was determined by continuing the linear dependence to its economic limit. A graph was plotted in semi-logarithmic coordinates for the analysis of production decline curves. According to the dependence of the water-oil ratio versus time, the type of early well flooding was determined in logarithmic coordinates.Conclusion. One of the most significant problems in the development of horizontal wells consists in the high water cut of the obtained products. According to the data for 2020, the average water cut in the main fields of Russia comprises at least 85%, with the mass ratio of produced oil and associated water approaching 1:7. The use of water-soluble polymers for waterproofing of horizontal wells can be considered a promising direction due to their efficiency in limiting water inflow in vertical and directional wells.

High-Performance Kinetic Hydrate Inhibition with Poly(N-isopropyl methacrylamide) and Triisopentylamine Oxide─Surprising Concentration-Dependent Results

Kinetic hydrate inhibitors (KHIs) are mostly used to prevent the deposition of gas hydrates in gas and condensate production flow lines. The main component in a KHI formulation is a water-soluble polymer, blended with solvents and other synergists to boost the performance. The performance limit in terms of subcooling and other factors restricts the application range of KHIs. Earlier, we reported on the synergetic performance of trialkylamine oxides with polyalkyl(meth)acrylamides using high-pressure steel rocking cell experiments. In particular, blends of poly(N-isopropyl methacrylamide) (PNIPMAm) in isobutyl glycol ether (iBGE) with triisopentylamine oxide (TiPeAO) gave exceptional KHI performance, better than what we have seen for any other KHI blend so far. Therefore, it is important to evaluate the limitations of this KHI. Here, we report the results of the KHI performance of this blend in more detail. The cloud point decreased with increasing salinity (0–15 wt % NaCl), but the blend remained soluble, giving excellent KHI performance even at the highest brine concentration. We also varied the concentration of the PNIPMAm/TiPeAO blend from 250 to 5000 ppm in deionized water in KHI slow constant cooling (SCC) tests using both a natural gas mixture [synthetic natural gas (SNG)] and methane gas. A unique concentration-dependent performance was discovered, wherein the performance decreased greatly above about 1500–2000 ppm, possibly due to aggregation of the polymer and amine oxide. This was observed for SCC tests with both SNG and methane, with the phenomenon being more pronounced for methane. In addition, an unusual double pressure drop was observed in SCC tests with methane and a blend of 5000 ppm PNIPMAm and TiPeAO. This study underlines the fact that overdosing of components in a synergistic blend can sometimes lead to detrimental effects on the KHI performance.

Water Soluble PMPC-Derived Bright Fluorescent Nitrogen/Phosphorous-Doped Carbon Dots for Fluorescent Ink (Anti-Counterfeiting) and Cellular Multicolor Imaging.

Here, a simple one-step hydrothermal-assisted carbonization process was adopted for the preparation of nitrogen/phosphorous-doped carbon dots from a water-soluble polymer, poly 2-(methacryloyloxy)ethyl phosphorylcholine (PMPC). By the free-radical polymerization method, PMPC was synthesized using 2-(methacryloyloxy)ethyl phosphorylcholine (MPC) and 4,4'-azobis (4-cyanovaleric acid). The water-soluble polymers, PMPC, that have nitrogen/phosphorus moieties are used to prepare carbon dots (P-CDs). The resulting P-CDs were thoroughly characterized by various analytical techniques such as field emission-scanning electron microscopy (FESEM) with energy-dispersive X-ray spectroscopy (EDS), high-resolution transmittance electron microscopy (HRTEM), X-ray diffraction (XRD), Raman spectroscopy, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Ultraviolet-visible (UV-vis) spectroscopy and fluorescence spectroscopy to determine their structural and optical properties. The synthesized P-CDs displayed bright/durable fluorescence, were stable for long periods, and confirmed the enrichment of functionalities including oxygen, phosphorus, and nitrogen heteroatoms in the carbon matrix. Since the synthesized P-CDs showed bright fluorescence with excellent photostability, excitation-dependent fluorescence emission, and excellent quantum yield (23%), it has been explored as a fluorescent (security) ink for drawing and writing (anti-counterfeiting). Further, cytotoxicity study results advised for biocompatibility and thus were used for cellular multicolor imaging in nematodes. This work not only demonstrated the preparation of CDs from polymers that can be used as advanced fluorescence ink, a bioimaging agent for anti-counterfeiting, and cellular multicolor imaging candidate, but additionally prominently opened a new perspective on the bulk preparation of CDs simply and efficiently for various applications.

Electrodepositing NiCo-double hydroxides with high electrochemical performance by adjusting the rheological behavior of electrolyte

Electrodeposition is a facile and convenient method to prepare NiCo double hydroxides for binder-free electrode materials that are equipped with superior electrochemical performance. But the samples synthesized by electrodeposition exhibit monotonous nanosheets array morphology and poor durability. In this paper, we proposed a novel electrodeposition way by introducing a water-soluble polymer, i.e. polyacrylamide (PAM) with different molecular weights (Mw) into the electrolyte to manipulate the morphology and electrochemical property. By adjusting the rheological behavior of the electrolyte, the NiCo hydroxides with different morphology can be acquired as the active materials can grow along the soft template constructed by polymer chains. The morphology of the active materials varies along with the concentration and molecular weight of the polymer as well. Furthermore, amorphous phases are accompanied by the crystal during the deposition. Benefit from the unique multilevel morphology and high specific surface area, the electrodes synthesized at the electrolyte containing an appropriate concentration of polymer exhibit higher specific capacitance and longer cycling performance than that prepared in the pure water system. This work provides a novel strategy to prepare double hydroxides with diverse morphology and electrochemical performance.

Synthesis and application of SeFe2O4@cell for the removal of polyethylene glycol from aqueous solution

Water pollution by water-soluble polymers is a severe emerging water challenge that needs urgent attention. Therefore, selenium ferrite immobilized on functionalized cellulose (SeFe2O4@Cell) was prepared for the purification of polyethylene glycol (PEG) polluted water. Characterization of SeFe2O4@Cell revealed the BET (Brunauer-Emmett-Teller) surface area to be 13.50 m2 g−1 and a total pore volume of 0.076 cm3 g−1. The crystallite size using X-ray diffraction (XRD) was 17.32 nm while the scanning electron micrograph (SEM) revealed a heterogeneous surface with irregular shaped particles. The adsorption capacity of SeFe2O4@Cell towards PEG is 39.20 mg g−1 with a percentage removal of 98%, which obeys the Freundlich isotherms. The adsorption mechanism was found to be via electrostatic interaction. The process is pseudo-second-order compliant, spontaneous, and endothermic with ΔHo (1.0055 kJ mol−1) and ΔSo (0.0042 kJ mol-1K−1) values within range that describes the process. Conclusively, the study presents SeFe2O4@Cell as a promising material that can be potentially used to purify water contaminated with PEG.

Preparation of Porous Aggregates of Smectite by Spray Drying Combined with the Intercalation of a Water-soluble Polymer

Donut shaped porous aggregates of a smectite with the size of several tens of micron were obtained by the spray drying of an aqueous suspension of the clay containing a block copolymer, P123. After calcination at 500 °C, the donut shape was retained and the BET surface area of the calcined product was ca. 200 m2/g, which was much higher than the product prepared without using P123. The roles of P123 for the formation of porous aggregate were discussed as the increased viscosity leading to the donut shaped aggregates by the spray drying and the suppression of the collapsing of the layered structure by the calcination.

Spiropyran-containing water-soluble and photoreversible copolymers

Photoreversibility in polymer design enables the control of physical properties using light, and in concert with water-solubility permits applications in aqueous environments. Inspired by environmental application, the primary goal of this paper is to develop a new synthesis pathway and to characterize the structure and functional behavior of spiropyran-containing photoreversible and water-soluble polymers. A one-step facile acylation reaction yielded the spiropyran-containing acrylate (SPA) monomer. Free radical copolymerization afforded a series of copolymers of SPA and oligo(ethylene oxide) monoacrylate monomer (OEOA) (Mn = 480 g/mol). Thermal analysis, including thermogravimetric analysis and differential scanning calorimetry, revealed the influence of SPA content on copolymer weight loss profile and OEOA side chain crystallization/melting. Copolymers exhibited good water solubility owing to the hydrophilic OEOA side chain. Solution rheology unveiled a shear-thickening effect related to the SPA pendent group and revealed the solution viscosity dependence on polymer concentration in aqueous solutions. In water, the designed spiropyran-containing polymers displayed photoreversibility and exhibited high photo-fatigue resistance with >90% of UV–vis absorbance preserved after five cycles. Preliminary Cu2+ complexation studies with SPA-co-OEOA copolymers indicated 88% removal of Cu2+ after UV irradiation, which suggests opportunities as light-responsive polymers for Cu2+ removal.

Phosphorus-Containing Polymers as Sensitive Biocompatible Probes for 31P Magnetic Resonance

The visualization of organs and tissues using 31P magnetic resonance (MR) imaging represents an immense challenge. This is largely due to the lack of sensitive biocompatible probes required to deliver a high-intensity MR signal that can be distinguished from the natural biological background. Synthetic water-soluble phosphorus-containing polymers appear to be suitable materials for this purpose due to their adjustable chain architecture, low toxicity, and favorable pharmacokinetics. In this work, we carried out a controlled synthesis, and compared the MR properties, of several probes consisting of highly hydrophilic phosphopolymers differing in composition, structure, and molecular weight. Based on our phantom experiments, all probes with a molecular weight of ~3-400 kg·mol-1, including linear polymers based on poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), poly(ethyl ethylenephosphate) (PEEP), and poly[bis(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)]phosphazene (PMEEEP) as well as star-shaped copolymers composed of PMPC arms grafted onto poly(amidoamine) dendrimer (PAMAM-g-PMPC) or cyclotriphosphazene-derived cores (CTP-g-PMPC), were readily detected using a 4.7 T MR scanner. The highest signal-to-noise ratio was achieved by the linear polymers PMPC (210) and PMEEEP (62) followed by the star polymers CTP-g-PMPC (56) and PAMAM-g-PMPC (44). The 31P T1 and T2 relaxation times for these phosphopolymers were also favorable, ranging between 1078 and 2368 and 30 and 171 ms, respectively. We contend that select phosphopolymers are suitable for use as sensitive 31P MR probes for biomedical applications.

Construction of fracturing fluid with excellent proppant transport capacity using low molecular weight hydrophobic association polymer and surfactant

Slick water fracturing fluid is widely used for fracturing unconventional reservoirs such as shale and tight gas, and it has aided in developing unconventional oil and gas reservoirs. However, the problem of slick water in terms of its weak proppant transport capacity has not been effectively solved. Conventional methods of increasing the proppant transport capacity of a fracturing fluid by increasing viscosity and pumping rate have resulted in serious reservoir damage and increased costs, showing more and more limitations. To address this issue, a low molecular weight polymer/surfactant (LMPS) fracturing fluid system was developed. LMPS increased the fluid elasticity through the interaction between the hydrophobic groups on the polymer and the surfactant while maintaining low viscosity, thus obtaining excellent proppant transport capacity. The low molecular weight polymer is a type of hydrophobic association water-soluble polymer (HAWSP) prepared by photoinitiation. Its viscosity-average molecular weight was determined to be 1.24 × 106 g/mol, much more than that of a typical drag reducer of traditional slick water (about 1 × 107 g/mol). The low molecular weight of HAWSP is conducive to preparation, dissolution, pumping, and reducing the damage of polymer to the reservoir. When 300 mg/L of sodium dodecyl benzene sulfonate (SDBS) surfactant was added to a 0.2 wt% HAWSP solution, it formed a robust self-assembled network that significantly enhanced the elasticity and raised the storage modulus G' from 0.11 to 5.95 Pa. The 20/40 mesh ceramsite proppant remained suspended in the LMPS solution (36 mPa·s) for 30 min, whereas ceramsite completely settled within 30 s in an ordinary linear polymer solution with similar viscosity. Simultaneously, despite having a lower molecular weight, the drag reduction rate test shows that the drag reduction performance of the LMPS fracturing fluid was similar to the tested conventional commercial linear polymer. The self-assembled network of HAWSP/surfactant can increase the viscoelasticity of the fracturing fluid, which is expected to overcome the weakness of insufficient proppant transport capacity of slick water, thus improving development efficiency of unconventional gas reservoirs.

Improved drug transfer into brain tissue via the “nose-to-brain” approach using suspension or powder formulations based on the amorphous solid dispersion technique

Intranasal administration has attracted increasing attention as a drug delivery approach based on nose-to-brain drug delivery from the nasal cavity to brain tissue directly, bypassing the blood–brain barrier. However, application of the method to poorly water-soluble drugs is potentially limited due to low aqueous solubility and dissolution, which can hinder drug transfer to brain tissue. In the present study, we focused on an amorphous solid dispersion (ASD) technique to improve drug dissolution. A carbamazepine-loaded ASD model drug was prepared using the solvent evaporation method (ASD-1). After screening six water-soluble polymer carriers, polyvinyl alcohol (PVA)-based ASD-1 formulation exhibited the most rapid and highest drug dissolution under experimental conditions in the nasal cavity (pH 6.0). A carbamazepine suspension dispersed with a PVA-ASD-1 formulation exhibited enhanced drug delivery into plasma and brain tissue of rats in vivo. A spray-dried powder formulation of PVA-ASD (PVA-ASD-2) exhibited improved drug dissolution and in vivo drug transfer. Our key finding is that the spray-dried PVA-ASD-2 formulation exhibited higher brain/plasma ratios than the PVA-ASD-1 suspension formulation. Our physical characterization data and demonstration of improved drug transfer suggest that ASD-based intranasal formulations hold promise for drug delivery to the brain.

Controlled solvothermal synthesis of ZnO nanoparticles using non-destructive Mg-based channel templates for enhanced photocatalytic performance

ZnO nanoparticles (NPs) were synthesized by solvothermal method using novel water soluble magnesium-based coordination polymers (MCPs) with rutile and anatase topologies as non-destructive templates. The strong interaction between ZnO–Mg(INT)2·H2O or ZnO-(Mg(NT)2 interface results in the increase of nucleation points and the decrease of grain sizes, and well-ordered growth of ZnO NPs via channel template effect. Comparing with other samples, S4 synthesized by the Mg(NT)2 template with anatase-type topology possesses the highest charge separation efficiency, largest surface area and pore volume, and exhibits the best photodegradation efficiency and k, which are 87.5%, 0.01752 min−1 (Rhodamine B, RhB) and 61.6%, 0.00776 min−1 (Tetracycline, TC) for 120 min, respectively. The photocatalytic efficiency for RhB over S4 changes slightly after five runs, which exhibits excellent photostability under ultraviolet–visible (UV–Vis) light irradiation. ·O2− and ·OH radical species play the important role in the photocatalytic process. Notably, the addition of MCP templates significantly improves active ·OH of ZnO via interface interaction, which is also favourable for the enhancement of photocatalytic performance of ZnO NPs. Additionally, photodegradation mechanism and pathways, and formation over ZnO were proposed. The work provides a new idea for designing non-destructive and easily-removed channel templates for the synthesis of ZnO NPs.

PSMA-Targeted Nanotheranostics for Imaging and Radiotherapy of Prostate Cancer.

Targeted nanotheranostic systems offer significant benefits due to the integration of diagnostic and therapeutic functionality, promoting personalized medicine. In recent years, prostate-specific membrane antigen (PSMA) has emerged as an ideal theranostic target, fueling multiple new drug approvals and changing the standard of care in prostate cancer (PCa). PSMA-targeted nanosystems such as self-assembled nanoparticles (NPs), liposomal structures, water-soluble polymers, dendrimers, and other macromolecules are under development for PCa theranostics due to their multifunctional sensing and therapeutic capabilities. Herein, we discuss the significance and up-to-date development of "PSMA-targeted nanocarrier systems for radioligand imaging and therapy of PCa". The review also highlights critical parameters for designing nanostructured radiopharmaceuticals for PCa, including radionuclides and their chelators, PSMA-targeting ligands, and the EPR effect. Finally, prospects and potential for clinical translation is discussed.

Mechanisms of pulmonary disease in F344 rats after workplace-relevant inhalation exposure to cross-linked water-soluble acrylic acid polymers

BackgroundRecently in Japan, six workers at a chemical plant that manufactures resins developed interstitial lung diseases after being involved in loading and packing cross-linked water-soluble acrylic acid polymers (CWAAPs). The present study focused on assessing lung damage in rats caused by workplace-relevant inhalation exposure to CWAAP and investigated the molecular and cellular mechanisms involved in lung lesion development.MethodsUsing a whole-body inhalation exposure system, male F344 rats were exposed once to 40 or 100 mg/m3 of CWAAP-A for 4 h or to 15 or 40 mg/m3 of CWAAP-A for 4 h per day once per week for 2 months (9 exposures). In a separate set of experiments, male F344 rats were administered 1 mg/kg CWAAP-A or CWAAP-B by intratracheal instillation once every 2 weeks for 2 months (5 doses). Lung tissues, mediastinal lymph nodes, and bronchoalveolar lavage fluid were collected and subjected to biological and histopathological analyses.ResultsA single 4-h exposure to CWAAP-A caused alveolar injury, and repeated exposures resulted in regenerative changes in the alveolar epithelium with activation of TGFβ signaling. During the recovery period after the last exposure, some alveolar lesions were partially healed, but other lesions developed into alveolitis with fibrous thickening of the alveolar septum. Rats administered CWAAP-A by intratracheal instillation developed qualitatively similar pulmonary pathology as rats exposed to CWAAP-A by inhalation. At 2 weeks after intratracheal instillation, rats administered CWAAP-B appeared to have a slightly higher degree of lung lesions compared to rats administered CWAAP-A, however, there was no difference in pulmonary lesions in the CWAAP-A and CWAAP-B exposed rats examined 18 weeks after administration of these materials.ConclusionsThe present study reports our findings on the cellular and molecular mechanisms of pulmonary disease in rats after workplace-relevant inhalation exposure to CWAAP-A. This study also demonstrates that the lung pathogenesis of rats exposed to CWAAP-A by systemic inhalation was qualitatively similar to that of rats administered CWAAP-A by intratracheal instillation.Graphical

Formation behavior of monolayers on the water surface of water-soluble thermoplastic and insoluble-thermosetting copolymers with hyperbranched units containing s-benzenetricarbamide cores

The formation and structure of Langmuir monolayers and Langmuir-Blodgett films were studied using water-soluble polymers, which have difficulty forming monolayers on the water surface, and polymers that are insoluble in all solvents. The network copolymers consisting of hyperbranched units with an s-benzenetricarbamide core used in this study can be freely controlled by azidation/non-azidation of both ends of the hard segment. The water-soluble copolymer, which exhibits the properties of a thermoplastic resin, can form a monolayer when spread on the water surface at a low temperature at which the solubility decreases. Even when the subphase temperature increased, no significant change in the monolayer behavior of the thermoplastic copolymer was observed. This behavior was attributed to the formation of an insoluble single-particle layer with hydrophilic groups facing inward on the water surface. The insoluble copolymer, which exhibits thermosetting properties, forms a tablet that floats on the water surface for an extended period. The surface pressure-time isotherms showed the formation of a monolayer from the tablet over time, and it was possible to measure the surface pressure-area isotherms by two-dimensional compression after a certain period of time.

Synthesis of Modified Poly(vinyl Alcohol)s and Their Degradation Using an Enzymatic Cascade.

Poly(vinyl alcohol) (PVA) is a water-soluble synthetic vinyl polymer with remarkable physical properties including thermostability and viscosity. Its biodegradability, however, is low even though a large amount of PVA is released into the environment. Established physical-chemical degradation methods for PVA have several disadvantages such as high price, low efficiency, and secondary pollution. Biodegradation of PVA by microorganisms is slow and frequently involves pyrroloquinoline quinone (PQQ)-dependent enzymes, making it expensive due to the costly cofactor and hence unattractive for industrial applications. In this study, we present a modified PVA film with improved properties as well as a PQQ-independent novel enzymatic cascade for the degradation of modified and unmodified PVA. The cascade consists of four steps catalyzed by three enzymes with in situ cofactor recycling technology making this cascade suitable for industrial applications.

Water-Resistant Photo-Crosslinked PEO/PEGDA Electrospun Nanofibers for Application in Catalysis

Catalysts are used for producing the vast majority of chemical products. Usually, catalytic membranes are inorganic. However, when dealing with reactions conducted at low temperatures, such as in the production of fine chemicals, polymeric catalytic membranes are preferred due to a more competitive cost and easier tunability compared to inorganic ones. In the present work, nanofibrous mats made of poly(ethylene oxide), PEO, and poly(ethylene glycol) diacrylate, PEGDA, blends with the Au/Pd catalyst are proposed as catalytic membranes for water phase and low-temperature reactions. While PEO is a water-soluble polymer, its blending with PEGDA can be exploited to make the overall PEO/PEGDA blend nanofibers water-resistant upon photo-crosslinking. Thus, after the optimization of the blend solution (PEO molecular weight, PEO/PEGDA ratio, photoinitiator amount), electrospinning process, and UV irradiation time, the resulting nanofibrous mat is able to maintain the nanostructure in water. The addition of the Au6/Pd1 catalyst (supported on TiO2) in the PEO/PEGDA blend allows the production of a catalytic nanofibrous membrane. The reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP), taken as a water phase model reaction, demonstrates the potential usage of PEO-based membranes in catalysis.

Transforming Polyethylene into Water-Soluble Antifungal Polymers

Petroleum-based polyolefin plastics currently possess highly unsustainable cradle-to-grave linear life cycles. Using them as a resource for the production of new functional polymers not only decreases the generated waste but also reduces our reliance on petroleum-derived monomers for traditional bottom-up synthesis of new polymeric materials. Herein, we demonstrate that polyethylene (PE), the most abundant plastic in production today, can be transformed into low-molecular-weight water-soluble antimicrobial polymers. In this proof-of-concept study, organocatalytic C–H aerobic oxidation of PE was first achieved to append reactive oxygenated and chloro functional groups onto the inert polymer chains, followed by further chemical modifications to form water-soluble amphiphilic polymers. Our first-generation polymer showed antimicrobial efficacy against opportunistic pathogenic Candida fungi without appreciable hemolysis even at high concentrations (2 mg/mL). The PE-derived antimicrobial polymer may find applications to combat the spread of fungal pathogens.