Sodium Methallylsulfonate Research Articles

Methallylsulfonate Polymeric Antiscalants for Application in Thermal Desalination Processes.

Nine copolymers of acrylic acid and sodium methallyl sulfonate were tested as scale inhibitors in thermal desalination. The nine antiscalants covered molar masses between 2000 and 9500 g.mol-1 and concentrations of sulfonated monomer ranging between 10 and 30 mole percent. A pressure measurement and control (P-MAC) unit and a high-temperature pressurized vessel were used to measure the effectiveness of the scale inhibitors in seawater, concentrated seawater, and model solutions at 125 °C. The effectiveness of the novel copolymers was comparable to commercial antiscalant at times up to 15 min and improved at longer times. Molar mass was a more important determinant of effectiveness than degree of sulfonation, with the greatest mitigation of calcium sulfate precipitation observed for antiscalants of molar mass 2000 to 2500 g.mol-1 regardless of sulfonate content. Antiscalants of molar mass 4500 to 5000 g.mol-1 showed a higher threshold effect than antiscalants of molar mass 7000 to 9500 g.mol-1, with a 30% sulfonated polymer of molar mass 4500 g.mol-1 performing appreciably better than other polymers of a similar molar mass.

Contribution of Adsorption and Hematocrit Levels to Ganciclovir Clearance in an in Vitro Continuous Hemodiafiltration Model.

Estimation of the continuous hemodiafiltration (CHDF) clearance (CLCHDF) of ganciclovir (GCV) is crucial for achieving efficient treatment outcomes. Here, we aimed to clarify the contribution of diafiltration, adsorption, and hematocrit level to the CLCHDF of GCV in an in vitro CHDF model using three membranes: polyacrylonitrile and sodium methallyl sulfonate copolymer coated with polyethylenimine (AN69ST); polymethylmethacrylate (PMMA); and polysulfone (PS). In vitro CHDF was performed with effluent flow rates (Qe) of 800, 1500, and 3000 mL/h. The initial GCV concentration was 10 µg/mL while that of human serum albumin (HSA) was 0 or 5 g/dL. The CLCHDF, diafiltration rates, and adsorption rates were calculated. The whole blood-to-plasma ratio (R) of GCV for a hematocrit of 0.1 to 0.5 was determined using blood samples with 0.5 to 100 µg/mL of GCV. The in vitro CHDF experiment using AN69ST, PMMA, and PS membranes showed that the total CLCHDF values were almost the same as the Qe and not influenced by the HSA concentration. The diafiltration rate exceeded 88.1 ± 2.8% while the adsorption rate was lower than 9.4 ± 9.4% in all conditions. The R value was 1.89 ± 0.11 and was similar at all hematocrit levels and GCV concentrations. In conclusion, diafiltration mainly contributes to the CLCHDF of GCV, rather than adsorption. Hematocrit levels might not affect the relationship between the plasma and blood CLCHDF of GCV, and the CLCHDF of GCV can be estimated from the Qe and R, at least in vitro.

The influence of continuous renal replacement therapy on 1,3-β-d-glucan levels in critically ill patients: a single-center retrospective propensity score study

1,3-β-d-Glucan (BDG) is commonly used for diagnosing invasive fungal infections (IFIs). While exposure to cellulose-based hemodialyzers is known to cause false-positive BDG results, the impact of modern hemofilters used in continuous renal replacement therapy (CRRT) remains unclear. This retrospective, single-center cohort study aimed to evaluate the effect of CRRT on BDG levels in critically ill patients. We included adult intensive care unit (ICU) patients with ≥1 BDG measurement between December 2019 and December 2020. The primary outcome was the rate of false-positive BDG results in patients exposed to CRRT compared to unexposed patients. Propensity score analysis was performed to control for confounding factors. A total of 103 ICU patients with ≥1 BDG level were identified. Most (72.8%) were medical ICU patients. Forty patients underwent CRRT using hemofilter membranes composed of sodium methallyl sulfonate copolymer (AN 69 HF) (82.5%) and of polyarylethersulfone (PAES) (17.5%). Among the 91 patients without proven IFI, 31 (34.1%) had false-positive BDG results. Univariable analysis showed an association between CRRT exposure and false-positive BDG results. However, the association between CRRT exposure and false-positive BDG results was no longer significant across three propensity score models employed: 1:1 match (n = 32) (odds ratio (OR) 1.65, p = .48), model-adjusted (n = 91) (OR 1.75, p = .38), quintile-adjusted (n = 91) (OR 1.78, p = .36). In this single-center retrospective analysis, exposure to synthetic CRRT membranes did not independently increase the risk of false-positive BDG results. Larger prospective studies are needed to further evaluate the association between CRRT exposure and false-positive BDG results in critically ill patients with suspected IFI.

In vitro analysis of factors affecting the continuous hemodiafiltration clearance of teicoplanin.

In the treatment of sepsis, continuous hemodiafiltration (CHDF) and the administration of antibiotics such as teicoplanin (TEIC) are frequently performed in parallel. We aimed to clarify the factors influencing the CHDF clearance (CLCHDF ) of TEIC using a polymethylmethacrylate (PMMA) membrane or a polyacrylonitrile and sodium methallyl sulfonate copolymer membrane coated with polyethylenimine (AN69ST). We also investigated whether the adsorption of TEIC onto the hemofilters inhibits the adsorption of interleukin (IL)-6 onto the membranes. TEIC, human serum albumin (HSA), and IL-6 were incubated with pieces of hemofilter membranes and adsorption rates were calculated. The CLCHDF , diafiltration rate, and adsorption rate of TEIC were calculated using an in vitro CHDF circuit model. The adsorption rates of TEIC onto the pieces of PMMA and AN69ST membranes ranged from 15.0% to 100% and from -10% to 5%, respectively. The adsorption rate of IL-6 was similar with or without TEIC. The CLCHDF and adsorption rate of TEIC under PMMA-CHDF depended on HSA, but not on effluent flow rate (Qe). The CLCHDF under AN69ST-CHDF depended on HSA and Qe. The observed CLCHDF under AN69ST-CHDF was similar to the predicted value (the product of Qe and the plasma unbound fraction). The observed CLCHDF under PMMA-CHDF was 2.0-7.8 times greater than the predicted value. Adsorption mainly contributes to the CLCHDF of TEIC using PMMA membranes, whereas diafiltration mainly contributes to the CLCHDF of TEIC using AN69ST membranes. TEIC adsorption might not affect the adsorption of IL-6 onto PMMA membrane.

Contribution of diafiltration and adsorption to vancomycin clearance in a continuous hemodiafiltration circuit model in vitro.

Vancomycin (VCM) is eliminated mainly by diafiltration under continuous hemodiafiltration (CHDF), but the contribution of adsorption to CHDF clearance (CLCHDF ) of VCM using a polyacrylonitrile and sodium methallyl sulfonate copolymer membrane coated with polyethylenimine (AN69ST) or a polymethylmethacrylate (PMMA) membrane is unknown. This study sought to investigate the contribution of diafiltration and adsorption to the CLCHDF of VCM using AN69ST and PMMA membranes in vitro. An in vitro CHDF circuit model was developed. The initial concentration of VCM was 50μg/mL and human serum albumin (HSA) was prepared at a concentration of 0, 2.5, or 5.0g/dL. The effluent flow rate (Qe) was set at 800, 1500, or 3000mL/h. The CLCHDF , diafiltration rate, and adsorption rate of VCM were calculated. Total CLCHDF of VCM using the AN69ST membrane increased and decreased with increasing Qe and HSA concentration, respectively. Diafiltration and adsorption rates were 82.1±9.8% and 12.1±6.1% under all conditions, respectively. Total CLCHDF using the PMMA membrane increased with increasing Qe. Diafiltration and adsorption rates were 89.2±20.4% and 4.6±17.0% under all conditions, respectively. The observed CLCHDF values significantly correlated with the predicted CLCHDF , calculated according to a previous study as the product of Qe and the plasma unbound fraction. Diafiltration predominantly contributed to CLCHDF of VCM using AN69ST and PMMA membranes. When diafiltration rather than adsorption mainly contributes to the CLCHDF of VCM, the CLCHDF could be predicted from the Qe and HSA concentration, at least in vitro.

A Puncture‐Resistant and Self‐Healing Conductive Gel for Multifunctional Electronic Skin

AbstractFlexible electronic skins (e‐skins) play a very important role in the development of human–machine interaction and wearable devices. To fully mimic the functions of human skin, e‐skins should be able to perceive multiple external stimuli (such as temperature, touch, and friction) and be resistant to injury. However, both objectives are highly challenging. The fabrication of multifunctional e‐skins is difficult because of the complex lamination scheme and the integration of different sensors. The design of skin‐like materials is hindered by the trade‐off problem between flexibility, toughness, and self‐healing ability. Herein, flexible sodium methallyl sulfonate functionalized poly(thioctic acid) polymer chains are combined with rigid conductive polyaniline rods through ionic bonds to obtain a solvent‐free polymer conductive gel. The conductive gel has a modulus similar to that of skin, and shows good flexibility, puncture‐resistance, notch‐insensitivity, and fast self‐healing ability. Moreover, this conductive gel can convert changes in temperature and strain into electrical signal changes, thus leading to multifunctional sensing performance. Based on these superior properties, a flexible e‐skin sensor is prepared, demonstrating its great potential in the wearable field and physiological signal detection.

A feasible and universal one-step method for functionalizing carbon dots efficiently via in-situ free radical polymerization

The passivation of carbon dots (CDs) are usually implemented through coupling reactions, which requires either specific functional groups on the surface of CDs or multiple steps. In this paper, we propose a feasible method to passivate CDs via in-situ free radical polymerization, which has no dependence on functional groups and thus is suitable for CDs prepared via either bottom-up or top-down route. Taking bare CDs that cut from active carbon by top-down method as an example. When putting acrylic acid, sodium methallyl sulfonate and acrylic phosphate ester as monomers into the bare CDs solution along with ammonium persulfate, stirring at room temperature for 2h, the monomers were polymerized and formed terpolymer-passivated CDs (T-CDs) of which quantum yields (QY) increased obviously. The QY of the bare CDs and the T-CDs were 0.2% and 29.1%, respectively. More interestingly, the bare CDs were found capable of constructing a redox-initiated couple with ammonium persulfate to initiate polymerization. Another example token to further approve the feasibility and universality of “in-situ free radical polymerization” passivation method is our reported poly (N-vinylcarbazole)-passivated CDs (PVK-CDs) that prepared by bottom-up method. The PVK-CDs were synthesized via thermal treatment of a mixture composed of citric acid and N-vinylcarbazole molecules at 300 °C for 2 h. During the process the citric acid was carbonized to provide pristine CDs and N-vinylcarbazole was in-situ polymerized on the surface of the pristine CDs through thermal initiation, which enhances the fluorescence QY up to 40%.

Synthesis of a starch-based sulfonic ion exchange resin and adsorption of dyestuffs to the resin

A starch-based ion exchange resin (SIR) was synthesized by copolymerizing raw starch with sodium methallyl sulfonate and styrene. The structural and surface properties of the SIR were characterized by 13C nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, gel permeation chromatography, scanning electron microscopy, X-ray diffractometry, thermogravimetric analysis, Brunauer–Emmett–Teller surface area analysis, and laser particle size analysis. The SIR was physicochemically and thermally stable and resistant to acids, bases, and enzymes. In static adsorption tests, the SIR had decolorization ratios (DRs) for mixed dyestuffs in wastewater of up to 84.04%, which was higher than the DR for a synthetic ion exchange resin (001 × 7, DR 77.14%). In dynamic adsorption tests, the SIR bed had a DR of 99.85% and a wastewater handling capacity 25 times the column volume. After three adsorption–regeneration cycles, the DR of the resin bed had decreased by <7.5%. The properties of the SIR, particularly the adaptability of the SIR to continuous column adsorption, make the SIR suitable for removing dyestuffs from industrial wastewater and a potential substitute for traditional sorbents such as activated carbon and synthetic resins.

Effect of PCEs with Different Functional Groups on the Performance of Cement Paste

The adsorption behaviors and dispersing properties of polycarboxylate superplasticizer (PCE) with different functional groups were systematically analyzed to reveal the theory and methods of modifying PCE molecular structures and regulating PCE performances. By substituting carboxylic groups with sulfonic groups, ester groups or acylamino groups, respectively, modified PCEs with different functional groups were synthesized. Results show that introducing low amount of ester groups or sulfonic groups into the PCE molecules has no negative effects on the fluidity of cement paste, while introducing acylamino groups into PCE molecules significantly weakens the fluidity of cement paste. At low amount (when the molar ratio of sodium methallyl sulfonate to TPEG is lower than 0.4), the rapid adsorption of sulfonic groups onto the cement particles contributes to the high dispersing performance of the sulfonic group modified PCEs. When the substitution ratio of acrylic acid by sulfonic acid is higher than 0.4, the viscosity and the yield stress of cement paste increases sharply. Redundant sulfonic groups lead to the excessive charge density of the PCE, which contributes to the inhomogeneous adsorption on the cement grains and hence results in the decline of the dispersing performance. Substitution of carboxylic group by acylamino group or ester group slightly changes the viscosity as well as the yield stress of cement paste. Introducing sulfonic group into PCE molecule improves the adsorption behavior of PCEs, while introducing ester group or acylamino group into PCE depresses the adsorption properties.

Regulating the arm structure of star‐shaped polycarboxylate superplasticizers as a means to enhance cement paste workability

ABSTRACTStar‐shaped superplasticizers, which incorporated polyol ester with unsaturated bond at their cores and bore comb‐type structures as their arms were synthesized via esterification‐copolymerization in aqueous phase from pentaerythritol, acrylic acid (AA), and isopentenyl oxy poly(ethylene glycol ether) (TPEG). The monomer ratios of AA and TPEG were varied and comonomer sodium methallyl sulfonate (SMAS) bearing short side chains was added to regulate the arm structure of star‐shaped polycarboxylate superplasticizers (SPCEs). The effects of the SPCEs on cement paste were investigated and the cement dispersion as well as early hydration mechanism were explored. As a main result, SPCEs with SMAS and certain molar ratios for anchoring groups and PEO side‐chains in their arm structure exhibited good paste dispersion and fluidity retention, which also delayed the early hydration process and prolonged both the initial and the final setting time. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46312.

Synthesis and Characterization of Linear Polycarboxylate Dispersant of Glacial Acrylic Acid−Maleic Acid−Sodium Methallylsulfonate for Ceramics

Synthesis and Characterization of Linear Polycarboxylate Dispersant of Glacial Acrylic Acid−Maleic Acid−Sodium Methallylsulfonate for Ceramics

Synthesis and Application of Itaconic Acid Water-Coke Slurry Dispersant

Polyethylene glycol (PEG-200) and itaconic acid (IA) were used as raw materials to compound macromer through esterification reaction. A new type of specialized water-coke slurry dispersant was synthesized by copolymerization of microware, sodium methallyl sulfonate (SMAS) and maleic anhydride (MA). The experiment showed that the concentration of slurry could be reached to 63% with the dosage of 0.2%, and the apparent viscosity was 1140.3 mPa∙s. Through the analysis of the infrared, the dispersant was confirmed to have polyethylene glycol branched chain and hydrophilic functional groups such as carboxyl or sulfonic group. When the concentration of dispersant was 30 g/L, the surface tension of water could be decreased from 72.70 mN/m to 45.50 mN/m. Furthermore, when the solution pH value was 9, the Zeta potential of semi-coke powder surface could also be decreased from-13.38 mV to-25 mV with the addition of dispersant. Thus, this dispersant could increase electronegativity of semi-coke powder surface, enhance steric-hindrance effect and prevent the phenomenon of powder flocculation and gather. Meantime, it also could reinforce the semi-coke hydrophilic by reducing the surface tension of water effectively. And then, the high performance water-coke slurry could be obtained.

Synthesis of High Performance Polycarboxylate Superplasticizer through Redox Initiation System and its Application in Concrete

A high performance polycarboxylate superplasticizer (PCE) was successfully synthesized by a polymerization reaction among acrylic acid (AA), maleic anhydride (MA) and isopentenyl polyethylene glycol (IPEG) through redox initiation system. The composition and amounts of initiation system, and the ratio of monomers were investigated respectively. The proportion of IPGE: MA: AA: sodium methallyl sulfonate (SMAS): ammonium persulfate (APS): ascorbic acid (ASA) was determined as 1: 3: 1.5: 0.3: 0.015: 0.012. Moreover, the effect of polymerization temperature on PCE’s cement paste fluidity was studied. The results showed that the cement pastes mixed with PCE synthesized at 10°C, 20°C and 30°C respectively exhibited better fluidity performances than that mixed with common PCE. The Fourier Transform Infrared Spectroscopy (FTIR) measurements were used for the structural characterization. The results confirmed the occurrence of polymerization reaction and the ideal structure. Furthermore, the application performances of PCE synthesized through redox initiation system in mortar and concrete were tested. The results showed that the water reducing rate of PCE in mortar and the slump performances of PCE in concrete were better than those of the common commercial PCEs. This synthesis method presents the great research value and application prospect for the PCE preparation in concrete engineering.

Synthesis and Application of a Cationic Polyacrylamide Dry Strength Agent with Anionic Content

A new net-cationic polyacrylamide dry strength agent was synthesized through free radical polymerization using acrylamide (AM), itaconic acid (IA), N,N-dimethylacrylamide (F), and sodium methallyl sulfonate (T). Ethylene diamine tetraacetic acid was used as a chelating agent; dimethylaminoethyl methacrylate methyl chloride (DMC) solution was used as a cationic monomer, and ammonium persulfate (APS) was used as an initiator. Orthogonal design and single-factor experiments were utilized to study the effect of many factors, such as reaction time, the ratio of monomers, and the dosage of APS and DMC on the cationic polyacrylamide. The synthesized products were characterized by Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), particle charge detector (PCD), and zeta potential analysis. The results showed that the optimum conditions were as follows: optimal monomer proportion: m(AM):m(IA):m(T):m(F) = 23.79:2.39:0.21:0.32; w (DMC) = 28%; w (APS) = 1.0%, reaction time was 3 hours, reaction temperature was 93 °C, stirring speed was 130 rpm, and reaction pH value was 3.0. The solid content of the polymer was 21.2%. By adding the cationic polyacrylamide to old corrugated container pulp, the tensile index increased by 29.7% and the burst index increased by 66.1%, displaying the obvious enhancement of the paper.

FT-IR Studies on the Cyclization Reaction of Acrylic Fibres

In this paper, chemical structure of three different acrylic fibres containing itaconic acid (IA), sodium methallyl sulfonate (SMS) and sodium 2-methyl-2-acrylamidopropane sulfonate (SAMPS) comonomers were studied by Fourier transform infrared (FT-IR) spectroscopy. This study was conducted in order to find the effects of precursor type acrylic fibres on the chemical interaction during the stabilization and on the properties of fabricated carbon fibres. The results of FT-IR show that the peaks related to C≡N bonds in acrylic fibres containing IA comonomer were completely removed during stabilization, while the peaks in SAMPS and SMS were just reduced. Also, the peak related to CH2 bond for acrylic fibres containing IA comonomer was reduced sharply in comparison with the other two fibres. These changes show that cyclization of nitrile groups and stabilization reactions in acrylic fibres having IA comonomer were completed. These reactions increase the tensile strength of carbon fibres produced from this material in comparison with other carbon fibres produced from acrylic fibres containing SAMPS and SMS.

Synthesis and Inhibition Efficiency of a Novel Quadripolymer Inhibitor

Abstract A novel quadripolymer scale inhibitor poly-maleic anhydride-acrylic acid-acrylamide-sodium methallyl sulfonate (PMAAS) was synthesized by solution polymerization with maleic anhydride (MA), acrylic acid (AA), acrylamide (AM), sodium methallyl sulfonate (SMAS), etc. IR spectrum shows that PMAAS contains carbonyl, hydroxyl, phosphatic and sulfonic acid group. SEM indicates that PMAAS blocks the normal growth of scale CaCO 3 and CaSO 4 crystals. The influences of PMAAS concentration, Ca 2+ concentration, temperature and pH value of the system on the inhibition efficiency are investigated. The inhibition efficiency of PMAAS is superior to commercial inhibitors T-225 and XF-192.

Biocompatibility Study Based on Differential Sequestration Kinetics of CD14+CD16+ Blood Monocyte Subsets with Different Dialyzers

The immune defect in hemodialysis (HD) patients is associated with a monocyte dysfunction, including an increase in the production of proinflammatory cytokines. Blood membrane contact leads to an increase in cellular activation and sequestration into the capillary bed of the lung. The influence of the sequestration on the number of mature monocytes was studied by analyzing the fate of monocytes, particularly, the CD14+CD16+ subpopulation, during HD treatment.In thirty stable HD patients, the distinct cell populations were determined by differential blood counts and flow cytometry. Patients with diabetes or systemic vasculitis, those showing evidence of infectious complications or malignancy, or those taking immunosuppressive medications were excluded from the study. Cells from this study population were analyzed before the start, 30 min thereafter, and at the end of HD treatment, each time using a different dialyzer: hemophan, methylmethacrylate (PMMA), triacetate membrane, cuprophane/vitamin E, acrylonitrile, and sodium methallylsulfonate polymer (AN69).The CD14+CD16+ subset decreased at 30 min and remained suppressed for the course of dialysis. To examine whether currently used biocompatible membranes differ in their effect on the sequestration of monocyte subpopulations, temporal monocytic changes were comparatively analyzed during HD with a different dialyzer. The drop in the first 30 min until the end of HD treatment was significant (p<0.05), very uniform, and sharp in all patients, and was independent upon membrane type.The CD14+CD16+ monocyte subpopulation showed increased and longer margination from the blood circulation during HD. Given the fact that CD14+CD16+ monocytes represent a sensitive marker for inflammation or cellular activation, the depletion of these cells may offer an easily accessible parameter that is more sensitive than complement activation for biocompatibility studies on forthcoming, improved dialyzer membranes.

A Proteomic Analysis of Human Hemodialysis Fluid

The vascular compartment is an easily accessible compartment that provides an opportunity to measure analytes for diagnostic, prognostic, or therapeutic indications. Both serum and plasma have been analyzed extensively by proteomic approaches in an effort to catalog all proteins and polypeptides. Limitations of such approaches in obtaining a comprehensive catalog of proteins include the fact that a handful of proteins constitute over 90% of plasma protein content and that the renal glomeruli filter out proteins and polypeptides that are smaller than 66 kDa from blood. We chose to study hemodialysis fluid because it contains a higher concentration of small proteins and polypeptides and is also simultaneously depleted of the most abundant proteins present in blood. Using gel electrophoresis in combination with LC-MS/MS, we identified 292 proteins of which greater than 70% had not been previously identified from serum or plasma. More than half of the proteins identified from the hemodialysis fluid were smaller than 40 kDa. We also found 50 N-terminally acetylated peptides that allowed us to unambiguously map the N termini of mature forms of the corresponding proteins. Several identified proteins, including cytokines, were only present as predicted transcripts in data bases and thus represent novel proteins. The proteins identified in this study could serve as biomarkers in serum using more sensitive methods such as ELISA-specific antibodies.

Membranes for biohybrid liver support: the behaviour of C3A hepatoblastoma cells is dependent on the composition of acrylonitrile copolymers

Co-polymers based on acrylonitrile, N-vinylpyrrolidone, aminoethylmethacrylate and sodium methallylsulfonate were used to prepare flat membranes by phase inversion. The surface properties of membranes were characterised by water contact angle measurements, atomic force microscopy and X-ray photoelectron spectroscopy (XPS). Membrane permeability was estimated by porosity measurements with water as test liquid. Human C3A hepatoblastoma cells were plated on these materials. Cell–material interaction was characterised by overall cell morphology, formation of focal adhesion contacts and intercellular junctions. Furthermore, cell proliferation was measured and compared with the functional activity of cells as indicated by 7-ethoxycoumarin-O-deethylation. More hydrophilic materials reduced spreading of cells, formation of focal adhesion and subsequent proliferation while homotypic cell adhesion was facilitated in correlation with stronger expressions of intercellular junctions and improved functional activity. In contrast, membranes with stronger adhesivity enhanced cell proliferation but reduced the functional activity of cells. It was concluded that the co-polymerisation of acrylonitrile with hydrophilic co-monomers, such as N-vinylpyrrolidone, could be used to tailor membrane materials for the application in biohybrid liver support systems.

Acrylonitrile–sodium methallylsulfonate copolymer. DSC approach to membrane porosity of foam and hollow fibers

The porosity of membranes formed from acrylonitrile–sodium methallylsulfonate copolymer was characterized from the analysis of the depression of the melting point of absorbed water. Membranes were obtained either as a foam or as a hollow fiber; the foam consisted of interconnected macrocavities (mean diameter about equal to 1 mm) while the hollow fiber was a symmetric membrane used for blood ultrafiltration. Differential scanning calorimetry (DSC) of water revealed both the Gaussian distribution of pore sizes and correspondingly, their mean size: 5.2 nm for the pores through the walls separating macrocavities in the foam and 5.6 and 10.6 nm associated with two distributions representing nearly equal amounts of absorbed water, for the hollow fiber. In addition to DSC, the water magnetic relaxation showed that the isothermal dehydration of the foam was due to the deswelling of macrocavities while the increasing amount of absorbed water in pores reflects its strong interaction with the polymer.