Acrylonitrile Copolymer Research Articles

Improved antifouling characteristics of acrylonitrile co-polymer membrane by low temperature pulsed ammonia plasma in the treatment of oil–water emulsion

Flat sheet polyacrylonitrile co-polymer membrane was treated by low temperature direct current ammonia plasma to enhance its antifouling characteristics. The surface properties, like, morphology, functional groups and wettability of the membrane were investigated by scanning electron microscopy, fourier transform infrared, X-ray photoelectron spectroscopy and contact angle. Enhancement in membrane hydrophilicity was monitored as function of plasma operating conditions, i.e., duty cycle and treatment time. Nitrogen and oxygen functional groups were identified to be responsible for surface hydrophilicity. The plasma treated membranes were used for separation of oil–water emulsion. It was found that the anti-fouling property of membrane improved remarkably after plasma treatment by enhancement of permeate flux without significant changes in oil rejection.

Preparation and Characterization of Facilitated Transport Membranes Composed of Chitosan-Styrene and Chitosan-Acrylonitrile Copolymers Modified by Methylimidazolium Based Ionic Liquids for CO₂ Separation from CH₄ and N₂.

CO2 separation was found to be facilitated by transport membranes based on novel chitosan (CS)–poly(styrene) (PS) and chitosan (CS)–poly(acrylonitrile) (PAN) copolymer matrices doped with methylimidazolium based ionic liquids: [bmim][BF4], [bmim][PF6], and [bmim][Tf2N] (IL). CS plays the role of biodegradable film former and selectivity promoter. Copolymers were prepared implementing the latest achievements in radical copolymerization with chosen monomers, which enabled the achievement of outstanding mechanical strength values for the CS-based membranes (75–104 MPa for CS-PAN and 69–75 MPa for CS-PS). Ionic liquid (IL) doping affected the surface and mechanical properties of the membranes as well as the gas separation properties. The highest CO2 permeability 400 Barrers belongs to CS-b-PS/[bmim][BF4]. The highest selectivity α (CO2/N2) = 15.5 was achieved for CS-b-PAN/[bmim][BF4]. The operational temperature of the membranes is under 220 °C.

Adsorption and release studies of cefuroxime sodium from acrylic ion exchange resin microparticles coated with gellan

Two types of microparticles based on acrylic ion exchange resin were prepared and used as macromolecular supports for the adsorption of an antibiotic (cefuroxime sodium salt) from aqueous solution. The first type of microparticles was synthesized by aqueous suspension copolymerization of acrylonitrile, ethylacrylate and ethylene glycol dimethacrylate followed by the aminolysis reaction of ternary copolymer with hydrazine hydrate. For the preparation of the second type of microparticles the gellan was selected to cover the surface of acrylic ion exchanger in order to increase the biocompatibility of these systems. Batch adsorption studies regarding the effects of various parameters such as, temperature, contact time, initial concentration of drug, drug:microparticles ratio and pH were studied. To study the adsorption kinetic mechanism, the Lagergren, Ho, Elovich and Weber-Morris particle diffusion models were applied and it was found that the adsorption of the drug could be described by pseudo first order equation (Lagergren model). The calculated values of thermodynamic parameters (ΔG, ΔH, ΔS) showed that the adsorption process was spontaneous and endothermic. The drug release process was found to be controlled by diffusion of drug molecules through polymer networks.

Synergistic toughening effect of chlorinated polyethylene and acrylic resin on SAN/ASA blends at low temperature

ABSTRACTStyrene–acrylonitrile copolymer (SAN)/acrylonitrile–styrene–acrylate terpolymer (ASA) blends (75/25, w/w) were toughened by blending with chlorinated polyethylene (CPE) and acrylic resin (ACR) at three different temperatures (−30, 0, and 25 °C). When the testing temperature was 0 and 25 °C, CPE played a key role in improving the impact strength of blends instead of ACR. However, an obvious synergistic toughening effect of CPE and ACR was observed at −30 °C: when both 10 phr CPE and 15 phr ACR were added, the impact strength of the blends reached a peak at 7.50 kJ/m2, which was about two to three times higher than when 25 phr CPE or 25 phr ACR was introduced into the blends individually. Scanning electron microscopy, dynamic mechanical analysis, and surface energy measurements were used to investigate the toughening mechanism. Furthermore, other mechanical properties and the heat distortion temperatures were evaluated. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43958.

Electrospun elastic acrylonitrile butadiene copolymer fibers

Abstract Nitrile rubber (NBR) is an unsaturated copolymer of acrylonitrile and butadiene. Due to its excellent oil-resistance, NBR products are widely used such as in the automotive and aerospace industries. This paper discusses the fabrication of acrylonitrile butadiene copolymer fibers via electrospinning. A transition from electrospray to electrospinning mechanism was observed and investigated by varying the solution composition. Diameter distributions and average diameters of the electrospun fibers from solutions of various copolymer weight concentrations were determined and compared. Water contact angles of both raw material and electrospun fiber mats were measured. Results indicated that the copolymer material was intrinsically hydrophobic, and the electrospun fiber mats showed higher hydrophobicity due to increased surface roughness. These properties were found to be strongly dependent upon the solution concentration. As the solution concentration increased, average fiber diameter increased and water contact angle decreased. Fiber mats of three different basis weights prepared from solutions of 5% copolymer concentration were prepared. Some of the mats were rolled into yarns. The flat mats and yarns were tested for uniaxial tensile strength to obtain data on their stress-strain performance. Comparison the stress-stain data for the flat mats and yarns showed similar properties. Evaluations of the performances of the fiber mats and yarns accounted for the fiber mat basis weights (mass of fibers per area of mat) and mat porosities through application of an idealized parallel fiber mat model. For small strains the stress-strain curves followed similar paths, but at large strains the paths deviated as fiber-fiber bonds slipped or fibers ruptured. For different basis weights, maximum tensile strengths of the flat mats and yarns were close, but slightly varied due to the more complex fiber structures compared to the idealized model. The yarns held larger stresses before rupture and possessed higher maximum tensile strengths than the flat mats attributed to the lower porosity of the yarns and additional bonds between fiber layers that are absent in the flat mats.

Synthesis and characterization of poly (acrylonitrile‐co‐acrylic acid) as precursor of carbon nanofibers

Synthesis of a co‐polymer of polyacrylonitrile (PAN) producing a carbon nanofiber out of PAN and co‐polymer of PAN and comparison between these products were examined. Free‐radical solution copolymerization of acrylonitrile (AN) with acrylic acid (AA) was studied. In this perspective, AA, and AN were used as a precursor for polymerization reactions; then copolymers were synthesized by using ammonium persulfate (APS) as an oxidant and carried in water/dimethylformamide (DMF) mixture. These polymers were used to obtain corresponding electrospun nanofibers. Synthesized P(AN‐co‐AA) was investigated by Fourier transform infrared spectroscopy‐attenuated total reflection (FTIR‐ATR) spectroscopy, and characteristic peaks for AN unit, AA were achieved. Thermal behavior was examined by using differential scanning calorimeter (DSC) and thermal gravimetric analyzer (TGA), and results indicated that addition of monomers to AN unit reduced the Tg value of homopolymer PAN compared to P(AN‐co‐AA), which provides improvement to the cyclization and the formation of a thermally stable aromatic ladder polymer chain formation. In order to prevent the shrinkage and maintain the molecular orientation on nanofiber webs during stabilization, tension was applied to the samples, and thermal oxidation varies at 200–300°C for different duration of times. Surface morphology of the fibers was observed with scanning electron microscope (SEM), and average nanofiber diameter was found 550 nm, and after carbonization it was reduced to 320 nm for homopolymer PAN, and for poly(AN‐co‐AA) average nanofiber diameter was found as 220 nm and reduced to 130 nm, respectively. Copyright © 2016 John Wiley & Sons, Ltd.

Coconut shell powder as cost effective filler in copolymer of acrylonitrile and butadiene rubber

Filler is one of the major additives in rubber compounds to enhance the physical properties. Even though numerous benefits obtained from agricultural by products like coconut shell, rice husk etc., still they constitute a large source of environmental pollution. In this investigation, one of the agricultural bye product coconut shell powder (CSP) is used as filler in the compounding KNB rubber. It shows the positive and satisfied result was achieved only by the use of filler Fast Extrusion Furnace (FEF) and coconut shell powder (CSP) which was used 50% in each. The effect of these fillers on the mechanical properties of a rubber material at various loading raging from 0 to 60PHP was studied. Mercaptodibanzothiazole disulphide (MBTS) was used as an accelerator. The result shows that presence of 25% and 50% of the composites has better mechanical properties like Hardness, Tensile strength, Elongation at break and Specific gravity when compared with other two combinations. Even though both 25% and 50% of composites shows good mechanical properties, 50% of CSP have more efficient than 25% of CSP.

Investigation of the dynamic mechanical properties of epoxy resins modified with elastomers

Abstract The mechanical and modal properties of epoxy resin reinforced with different content of carboxyl-terminated butadiene acrylonitrile copolymer (CTBN) rubber were investigated in this paper with an analytical-experimental identification method. Mechanical tensile tests were conducted for concentrations between 0 and 25wt% of CTBN rubber. The dynamic responses of the epoxy/CTBN rubber composites were measured by vibrating cantilever beam specimens with an impact force through a modal hammer, while the vibratory response was detected through an acceleration transducer. The analytical-experimental transfer function method is utilized for the deduction and therefore comparison of the elasticity modulus of the epoxy/rubber composites. The procedure for the identification of analytical-experimental transfer functions was carried out using a genetic algorithm (GA) by minimizing the difference between the measured response from tests and the calculated response, which is a function of the modal parameters. Both tensile and modal tests have shown, while it was evident from the results that the CTBN composites could absorb greater amounts of strain energy. The modal test results indicate that CTBN rubber particles can improve the damping capacity of the epoxy-based composites. However, it was observed that the stiffness of the epoxy/CTBN rubber composites was dramatically reduced.

Hybrid imprinted membranes for selective recognition of quercetin

Abstract Hybrid imprinted membranes exhibiting specific recognition properties towards the quercetin (the template) were developed. In this perspective, an imprinted copolymer of acrylonitrile, using acrylamide as functional co-monomer was synthesized. For comparison, a non-imprinted polymer was also prepared. Various membranes were produced by dispersing different copolymer amounts in a poly(ether ether ketone) (PEEK-WC) matrix. Scanning Electron Microscopy, and Fourier Transform Infrared analysis confirmed the presence of the polymer into the hybrid system. Membrane permeability was in the ultrafiltration range (70–180 l/h m 2 bar). The addition of polymer to the support membrane determined a slight decrease of the membrane hydrophobicity. The solvent uptake degree was very low (between 1.2% and 1.32%), suggesting a weak interaction between the polymer and the binding solvent. No significant change in the mechanical properties were observed. The membranes recognized the quercetin in different extend. The highest imprinting factor (3.6) and binding capacity (12.0 mol/g memb .) was exhibited by the membranes containing the 25 wt.% of the imprinted polymer (PEEK-WC/25% MIP). This membrane was also selective v s chrysin and naringin, (structural homologs of quercetin). The selectivity factor quercetin/naringin was 4.5 and that one of the couple quercetin/chrysin was 1.8. The Langmuir adsorption model was suitable for correlation of equilibrium data. The kinetic of quercetin adsorption of PEEK-WC 25% MIP membrane was efficiently predicted by the second-order model.

The nature of sites of absorption of low-molecular-mass compounds by butadiene–acrylonitrile copolymers

The rotational mobilities of the paramagnetic probes TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) and BZONO (4-benzoate-2,2,6,6-tetramethylpiperidine-1-oxyl) are studied via EPR spectroscopy and the equilibrium swelling of random and multiblock butadiene–acrylonitrile copolymers of various compositions and stereostructures of butadiene units in n-heptane, methyl acetate, and toluene are studied. The nature of defective regions sorbing low-molecular-mass compounds is ascertained. The rotational mobilities of the probes in defects of various structures are estimated. The sites of sorption are found to be identical in crosslinked and noncrosslinked elastomers. It is shown that the sorption of n-heptane and methyl acetate appears in the same defective regions as those of the TEMPO radical, while the sorption of toluene emerges in sorption sites where the value of free volume is sufficient for the sorption of the bulky radical BZONO. A decay in local molecular mobility in structural defects (“holes”) does not hinder the absorption of lowmolecular- mass compounds if the free volume is sufficient.

Ionic Conducting and Surface Active Binder of Poly (ethylene oxide)-block-poly(acrylonitrile) for High Power Lithium-ion Battery

In this work, poly(ethylene oxide)-block-poly(acrylonitrile) (PEO-b-PAN) copolymer is used as a binder for LiFePO4 cathodes, where PEO-b-PAN not only conducts Li+ inside the cathode but also acts as a dispersant to disperse LiFePO4. This binder significantly increases the capacity under high discharge rate and overcome the limitation of LiFePO4 for high power density application. By XPS analysis, the incorporation of the PEO-b-PAN binder to the active materials of the LiFePO4 cathodes can be clearly observed from the binding energy of the nitrogen atom of the PEO-b-PAN. Due to the surface active properties of the PEO and PAN, PEO-b-PAN obviously increases the effective contact area and reduces electronical resistance. In addition to the surface active properties, this binder provides Li+ pathway; thus, it features low polarization, less interfacial resistance and good activity for electrochemical reaction. Consequently, these properties enable the PEO-b-PAN binder to have a higher discharge plateau potential at 3.10V, while it is only 2.86V for the PVDF binder at a 5C rate. Moreover, even at a 10C rate, the PEO-b-PAN binder still delivers extraordinary discharge capacities of 101mAhg−1, significantly higher than that of the PVDF binder (32mAhg−1). Overall, this ionic conducting and surface active binder exhibits good electrochemical properties and excellent high rate performance.

Low-cost poly(vinyl chloride)/poly(α-methylstyrene-acrylonitrile)/chlorinated polyethylene/mineral fillers composites with highly improved thermal conductivity I: Mechanical and thermal performance

Low-cost mineral fillers, including mica, calcium carbonate (CaCO3), and alumina oxide (Al2O3) were used to modify poly (vinyl chloride) (PVC)/α-methylstyrene–acrylonitrile copolymer (α-MSAN)/chlorinated polyethylene (CPE) blend. With the addition of mineral fillers, the thermal conductivity, flexural modulus and overall thermal stability were improved; however, loss in tensile properties, impact and flexural strength, and initial thermal stability accompanied the other improved properties. The theoretical modeling results indicate that Mica has a more effective potential to increase the thermal conductivity and better interfacial interaction with the polymeric matrix. Therefore, mica is the best candidate for enhancing the properties of the composites. POLYM. COMPOS., 2016. © 2016 Society of Plastics Engineers

Synthesis of highly water selective copolymer membranes for pervaporative dehydration of acetonitrile

Pervaporative dehydration of highly concentrated (90–99.9%) acetonitrile needs a chemically resistant membrane having high water selectivity. Crosslinking is the usual practice of controlling excessive swelling in solvent and increasing selectivity of a hydrophilic membrane at the cost of flux. A membrane prepared from a copolymer of acrylonitrile and itaconic acid would be chemically resistant due to its acrylonitrile moiety and also hydrophilic due to the presence of bicarboxylic itaconic acid in its structure. Further, crosslinking is not required for preparing this copolymer membrane. Thus, in the present work several hydrophilic membranes were prepared by copolymerizing acrylonitrile (AN) and itaconic acid (IA) at varied molar ratios depending on their relative reactivity ratios. The structure of the copolymer was characterized by FT-IR, XRD and TG-DTA. The membranes prepared with an AN: IA molar ration of 15:1, 12:1 and 10:1 and noted as PANIA1, PANIA2 and PANIA3, respectively showed optimum properties, viz., mechanical stability, flux and selectivity. Thus, for 99wt% acetonitrile in feed at 30°C, these membranes showed a thickness normalized flux of 1.7, 1.8 and 1.9kgμm/m2h and a high water selectivity of 459, 429 and 409, respectively.

Toughening effect of CPE on ASA/SAN binary blends at different temperatures

ABSTRACTThe effect of chlorinated polyethylene (CPE) on the impact toughness of acrylonitrile–styrene–acrylic (ASA) terpolymer/styrene–acrylonitrile copolymer (SAN) binary blends (25/75, w/w) was systematically investigated at three different temperatures (−30 °C, 0 °C, and 23 °C). With the addition of 60 phr CPE, the impact strength increased by 11 times at 23 °C and 10 times at 0 °C. However, the toughening effect was not obvious when the testing temperature was −30 °C. Since the glass‐transition temperature (Tg) of CPE was about −18.3 °C as measured with dynamic mechanical analysis tests, the polymeric chains of CPE have been “frozen out” at −30 °C. As a result, CPE evidently cannot improve the toughness of the blend system. The morphology of impact‐fractured surfaces observed by scanning electron microscopy also confirmed the effect of CPE on the impact toughness of ASA/SAN binary blends. The heat distortion temperature remained almost unchanged, indicating that the improvement in toughness did not sacrifice heat resistance. Furthermore, other mechanical properties were evaluated, and the possible interactions among components of the blends were also analyzed by Fourier transform infrared spectra. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43353.

Ultrasensitive pH-Induced Water Solubility Switch Using UCST Polymers

For some thermosensitive polymers, the absence of an upper critical solution temperature (UCST) in water in an accessible temperature range (say, 5–90 °C) can be attributed to the influence of charged groups in the polymer structure. This property was exploited in the present study to achieve ultrasensitive pH-induced water solubility switch of UCST polymers in physiological medium. By incorporating either acrylic acid (AAc) or 4-vinylpyridine (4VP) comonomer units in the random copolymer of acrylamide and acrylonitrile (P(AAm-co-AN-co-AAc) or P(AAm-co-AN-co-4VP)), the pH-induced shift of UCST was investigated by monitoring the solution cloud point. The results revealed an unusually large shift of the cloud point upon pH variation over a small range. In particular, one P(AAm-co-AN-co-4VP) sample exhibited a cloud point drop from 72 °C at pH 4.75 to 15 °C at pH 4.50 (i.e., 57 K shift over 0.25 pH units), and its transition from soluble to insoluble state at room temperature was visually observable over a p...

PH dependent thermoresponsive behavior of acrylamide–acrylonitrile UCST-type copolymers in aqueous media

pH-dependent UCST-transitions and influence of sacrificial additives on the thermoresponsivity of acrylamide- acrylonitrile copolymers is shown.

Hierarchy of Structural Associates of Catalytically Active Sites on an Acrylonitrile-Based Polymeric Fibrous Carrier

The characteristic features of the structural hierarchy of the formation of iron-containing catalytic sites on polymeric carriers based on modified polyacrylonitrile and copolymer of acrylonitrile with methyl acrylate were determined using optical and X-ray spectroscopy. It has been shown that some of the short ring structures that appear in the creation of a polydentate ligand lose their ability to coordinate the metal and may not be included in the composition of catalytically active particles entering the complex formation reaction.

Anionic polymerization and copolymerization of acrylonitrile initiated by systems based on bicyclic tertiary amines and ethylene oxide

It is shown that the products of interaction of ethylene oxide and bicyclic amines containing tertiary nitrogen atoms at the tops of bicyclic structures efficiently initiate the anionic polymerization of acrylonitrile. As opposed to all known initiators of this process, the mentioned initiating systems contain no metal atoms or atoms of elements heavier than oxygen. The polymerization of acrylonitrile under the action of the ethylene oxide–bicyclic amine system in a polar medium (dimethyl sulfoxide) at room temperature occurs in the homogeneous regime over several minutes, while, in a weakly polar solvent (tetrahydrofuran), polymerization occurs in the heterogeneous regime over several hours. The reaction may become homogeneous in a mixture of these solvents at both room temperature and a lower temperature. The number-average molecular masses of the polymers, depending on polymerization conditions, are in the range from 25 × 103 to 480 × 103 and their polydispersity indexes are from 1.55 to ~3.40. It is found that the copolymers of acrylonitrile with oxygen-containing acrylic monomers, as well as with ethylene oxide, can be prepared.

Design and development of a poly(acrylonitrile-co-methyl methacrylate) copolymer to improve the viscoelastic and surface properties critical to scratch resistance

The present paper reports the design, development and evaluation of methyl methacrylate (MMA) and acrylonitrile (AN) copolymers to improve viscoelastic and surface properties critical to scratch resistance.

Fabrication of sponge-like α-Ni(OH)2on styrene–acrylonitrile copolymer (SAN)-derived carbon spheres as electrode materials for supercapacitor application

Styrene–acrylonitrile copolymer particles (SANPs) were synthesized through dispersion polymerization.