Acrylonitrile Copolymer Research Articles

Membranes Based on Cellulose and Copolymers of Acrylonitrile Prepared from Joint Solutions.

Cellulose and copolymers of acrylonitrile (PAN) are characterized by their chemical resistance to several conventional solvents. Therefore, these polymers are often used to obtain membranes for the recovery of such solvents. In this work, for the first time, composite membranes formed from highly concentrated mixed solutions based on cellulose and PAN are considered (the total content of polymers is 18 wt.%). For mixed solutions, the morphology and rheological behavior were evaluated. It is shown that the resulting solutions are two-phase, and their morphology depends on the components' ratio and the system's history. The non-monotonous change in the viscosity with the PAN content indicates a specific interaction of cellulose and PAN in N-methylmorpholine-N-oxide solutions. The rheological behavior of mixed solutions allows for their processing in conditions identical to those of cellulose solutions. The introduction of PAN into the cellulose matrix promotes a decrease in the structural order in the system, affecting the membranes' transport properties. For composite membranes, it was found that with an increase in the content of the PAN phase, the retention of Remazol and Orange decreases, while the observed values are several times higher than those for cellulose membranes. The permeability of ethanol increases with increasing terpolymer content.

Synthesis and thermal behavior of RAFT-based copolymers of acrylonitrile and 1-vinylimidazole

The copolymers of acrylonitrile and 1-vinylimidazole with a narrow molecular weight distribution (MWD) were synthesized for the first time by the reversible addition–fragmentation chain transfer (RAFT) polymerization in a DMSO solution in the presence of acetic acid. Their thermal behavior difference upon heating in argon and in air along with ability to melt make them promising precursors for carbon fiber production.

NMR spectroscopy based configurational and compositional analysis of isobornyl methacrylate—Acrylonitrile copolymers

The authors conducted free radical polymerization using an initiator to synthesize a copolymer of isobornyl methacrylate—Acrylonitrile (I/A). The reactivity ratios of I (r1) and A (r2) monomers were determined as r1 = 1.63 ± 0.14, r2 = 0.61 ± 0.06 for linear KT (Kelen–Tudos) method and r1 = 1.58, r2 = 0.60 for the EVM (Error-in-Variable Method). We interpreted 1H and 13C{1H} NMR spectra of the I/A copolymers using DEPT-135 and 2D HSQC spectra. The α-CH3 carbon in the I-unit was identified and confirmed using a 2D HSQC NMR spectrum, up to the level of triad of compositional and configurational sequences. The CH (C14) and β-CH2 carbon peaks were also identified up to the triad level and higher, respectively. A 2D TOCSY spectrum revealed geminal and vicinal interactions within various CH and β-CH2 protons. A 2D HMBC NMR spectrum provided a complete assignment of the coupling between nitrile, carbonyl, and quaternary carbons with CH3 and CH2 protons.

Plastiglomerates from uncontrolled burning of plastic waste on Indonesian beaches contain high contents of organic pollutants

This study reports on plastiglomerate and other new forms of plastic pollution in the tropical marine continent of Indonesia. Twenty-five samples were collected from an island beach in the Java Sea where plastiglomerate, plasticrusts, and pyroplastic were formed by the uncontrolled burning of plastic waste. The most common plastic types were polyethylene and polypropylene (PE/PP), as shown by ATR-FTIR spectroscopy. However, acrylates/polyurethane/varnish (PU) and a copolymer of styrene and acrylonitrile were found as well. This suggests that plastiglomerates can form from a wider variety of plastic polymers than previously reported. FTIR analysis also indicates thermo-oxidative weathering, making the charred plastic more brittle and susceptible to microplastic formation. A subset of the samples was analyzed for associated chemical contaminants. One plastiglomerate with a PU matrix showed high concentrations of phthalates. All samples had high concentrations of polycyclic aromatic hydrocarbons (PAHs), likely due to the burning of the plastic in open fires. The burning leads to a change in the physical and chemical properties of the plastics contained in the plastiglomerates. Plastiglomerate and plastic waste of similar origin are therefore often more weathered and contaminated with organic pollutants than their parent polymers. The highest PAH concentration was found in a plastitar sample. Plastitar is defined as an agglomerate of tar and plastics that adheres to coastal rocks. In contrast, our study documents a more mobile, clastic plastitar type. This clastic plastitar could pose an additional ecological risk because of its mobility. These new types of plastic pollution could be an important vector for chemical contamination of nearby coastal habitats such as coral reefs, seagrass meadows, and mangroves.

Fraction of Free Volume in Defective Structures of Butadiene and Acrylonitrile Copolymers and Absorption of Low Molecular Compounds

Fraction of Free Volume in Defective Structures of Butadiene and Acrylonitrile Copolymers and Absorption of Low Molecular Compounds

Synthesis of amphiphilic functional terpolymers towards preparation of high flux, anti-fouling, micropollutant-capturing ultrafiltration membranes

Traditional method for modification of PVC ultrafiltration membrane depends mainly on blending, but inevitably suffers from additive leakage and poor compatibility between components. Herein, we synthesized amphiphilic functional terpolymers with adjustable chemical structures through in-situ copolymerization of vinyl chloride, acrylonitrile, and dimethyl aminoethyl acrylate, subsequently prepared the terpolymer ultrafiltration membranes by non-solvent induced phase separation. The novel terpolymers endow the membranes with amphiphilic and pH-responsive performances. Compared with the blend membrane, the copolymer had the more stable covalent bonding, and then its hydrophilic segments could anchor and enrich stably to the membrane surface without diffusing into the aqueous phase. As a result, the copolymer membrane not only effectively overcame the disadvantages of blend membrane, but also showed excellent antifouling and permeable properties. Its water flux significantly increases to 469.41 L/(m2·h·bar) from 35.67 L/(m2·h·bar) of pure PVC membrane while the adsorption capacity for bovine serum proteins was reduced. Meanwhile, the copolymer membranes exhibited strong pH-dependent adsorption for anionic dyes and heavy metal ions. The maximum adsorption capacities occurred respectively at pH values of 3.5 and 6.0. In addition, the copolymer membrane can be regenerated by desorbing the adsorbed anionic dyes and heavy metal ions respectively at pH 10 and pH 3.5. This research provides a new strategy for facile preparation of amphiphilic functional ultrafiltration membranes and effective removal of micropollutants.

Analytical Steady-State Model for the Free Radical Solution Copolymerization of Acrylonitrile and Vinyl Acetate and Their Charge-Transfer Complex in a Continuous Stirred Tank Reactor

In this study, a mathematical model of the copolymerization of AN-VA in a continuous stirred tank reactor (CSTR) was developed considering charge-transfer complexes (CTCs). CTC formation between acrylonitrile (AN) and vinyl acetate (VA) was demonstrated using UV-VIS spectrophotometry and molecular orbital theory. The rate constants and equilibrium constants of the complexes were calculated from a model of the simultaneous participation of complexes and free monomers and the molar ratio method. Furthermore, the participation of CTCs in propagation was included because of their high reactivity. All the simultaneous equations defined to analyze the reactor parameters were analytically solved, and the results of the model were in terms of operative variables such as monomer conversion, average molecular weight, and the mole fraction of monomer 2 (i.e., VA) in the polymer formed. The results of the predictions of the developed model were compared with the experimental data for validation. This prediction was also compared with the reactor model solution without considering the CTC, which showed deviations that were more significant than those of the CTC model. These results represent a quantitative way to analyze the order of magnitude of the impact of the formation of the complexes in the analyzed polymerization system.

Sodium Salt of Partially Carboxymethylated Sodium Alginate-g-Poly(acrylonitrile): I. Photo-Induced Synthesis, Characterization, and Alkaline Hydrolysis.

An efficient redox initiating system, ceric ammonium nitrate/nitric acid, has been employed for the first time to carry out photo-induced graft copolymerization of acrylonitrile (AN) onto sodium salt of partially carboxymethylated sodium alginate, having an average degree of substitution value to be 1.10. The photo-grafting reaction conditions for maximum grafting have been systematically optimized by varying the reaction variables such as reaction time, temperature, the concentration of acrylonitrile monomer, ceric ammonium nitrate, and nitric acid, as well as the amount of the backbone. The optimum reaction conditions are obtained with a reaction time of 4 h, reaction temperature of 30 °C, acrylonitrile monomer concentration of 0.152 mol/L, initiator concentration of 5 × 10-3 mol/L, nitric acid concentration of 0.20 mol/L, amount of backbone of 0.20 (dry basis) and the total volume of the reaction system of 150 mL. The highest percentage of grafting (%G) and grafting efficiency (%GE) achieved are 316.53% and 99.31%, respectively. The optimally prepared graft copolymer, sodium salt of partially carboxymethylated sodium alginate-g-polyacrylonitrile (%G = 316.53), has been hydrolyzed in an alkaline medium (0.7N NaOH, 90-95 °C for ~2.5 h) to obtain the superabsorbent hydrogel, H-Na-PCMSA-g-PAN. The chemical structure, thermal characteristics, and morphology of the products have also been studied.

Miscibility of nitrated poly(phenylene oxide) and styrene–acrylonitrile copolymer blends

AbstractPoly(2,6‐dimethyl‐1, 4‐phenylene oxide) (PPO) is a well‐known high heat‐resistant polymer and miscible with polystyrene. However, it is not miscible with many polymers containing polar groups. In the present study, PPO was nitrated to prepare a nitrated PPO (NPPO) containing polar nitro groups and blended with a copolymer of styrene/acrylonitrile (SAN). Dynamic mechanical analysis (DMA) data showed that NPPO in SAN‐rich phase was miscible with SAN, while NPPO in NPPO‐rich phase was partially phase‐separated from SAN, both over the entire blend composition range from NPPO wt. fractions of 0.1–0.5 investigated for this work. Analyses of Fourier‐transform infrared (FTIR) and ultra‐violet (UV–VIS) spectra indicated that the miscibility of NPPO with SAN was caused by intermolecular hydrogen bonding of CN group of SAN with OH end‐group of NPPO in the NPPO/SAN blends. NPPO's OH end‐group, meta‐nitro 2,6‐dimethyl phenol, was produced during nitration of PPO due to chain scission of aryl ether bond. Besides the intermolecular hydrogen bonding, dipole‐diplo interaction of the CN and nitro groups resulted in dissociation of the CN dimers and trimers to the CN monomers in the NPPO/SAN blends.

Preparation of a Structural Polyimide Foam Plastic Based on a Bulk Copolymer of Acrylonitrile and Methacrylic Acid

Preparation of a Structural Polyimide Foam Plastic Based on a Bulk Copolymer of Acrylonitrile and Methacrylic Acid

Study of mechanical properties of epoxy/graphene and epoxy/halloysite nanocomposites

Abstract This article aimed to compare various mechanical properties of epoxy/graphene and epoxy/halloysite nanocomposites. Graphene nanoplatelets (GnPs) and halloysite nanotubes (HNTs) were used as fillers at different concentrations. The studied fillers were dispersed in the epoxy resin matrices. Elastic–plastic mechanical behavior modulation was observed utilizing the fillers’ nanoparticles and carboxyl-terminated butadiene–acrylonitrile copolymer rubber-modified epoxy resin. The hypothesis of the possible preceding inter-particle gliding of the individual GnPs in the complex resin nanocomposite matrix during mechanical testings was also confirmed. Increased ductility (elongation at break increased from 0.33 mm [neat matrix] to 0.46 mm [1 wt% GnPs] [39% increase]) and plasticity of the GnP nanocomposite samples were observed. In contrast, the decreasing mechanical stiffness as reflected in the decreased Young’s modulus of elasticity (from 3.4 to 2.7 GPa [20% decrease]) was found for the epoxy/HNT nanocomposites. The obtained dynamic stiffness of the investigated nanocomposites confirmed the complexity of the mechanical response of the studied material systems as a combination of the ductile and brittle phenomena.

Degradation behavior of multilayer packaging films in the presence of a highly acidic sauce

Highly acidic condiments such as hot sauce can deteriorate multilayer packaging films. To date, only a multilayer polymeric film (polyethylene terephthalate/ink/polyethylene/foil/polyethylene/SiO x coated polyethylene terephthalate/adhesives/Barex®) utilizing a proprietary resin, Barex® as one of its polymeric layers can preserve hot sauce for military rations. However, the production of Barex® stopped in 2016. To identify substitutes for Barex®, an immersion study of films in hot sauce was conducted with several commercially available multilayer films (Polyethylene terephthalate/ink/adhesive/polyamide/adhesive/polypropylene and polyethylene terephthalate/waste low-density polyethylene/aluminum foil/adhesive/polyester/low-density polyethylene) and a monolayer Barex® (acrylonitrile methyl acrylate copolymer) film. All films were immersed in hot sauce, acetic acid, and sodium chloride solutions at 50 °C for 12 weeks. The mass, thickness, morphology, and chemical compositions of each film were analyzed every three weeks. Hot sauce and acetic acid solution similarly deteriorated multilayer films, causing delamination and oxidative degradation, but not sodium chloride solutions. This indicates that the failure of the multilayer packaging of hot sauce was likely caused by the low pH environment, not heat or salt ions. The two primary innovations in this study are: 1) the finding that acidic components in hot sauce deteriorate multilayer packaging by transforming aluminum foil into a soluble salt and by oxidizing polyethylene, and 2) surface erosion plays a significant role in inducing polyethylene oxidation. This is the first study to describe how a highly acidic food deteriorates multilayer packaging used for military rations. Possible deterioration mechanism of the multilayered structure (Film 2) in presence of a highly acidic hot sauce. • Acetic acid in hot sauce reacts with aluminum foil used in multilayer films. • Acids in hot sauce oxidatively degrade polyethylene (PE) layers in multilayer films. • PE in multilayer films oxidizes more in hot sauce than in acetic acid solutions. • PE in multilayer films surface erodes when immersed in hot sauce and acetic acid. • Potential multilayer film is identified for replacing Barex® for military rations.

Network structure and viscoelastic behavior of high-strength crystal microphase crosslinking hydrogels analyzed from combined model

The design of network structure is vital to the preparation of high-strength hydrogels. Using a mechanical model to analyze the network structure and mechanical behavior of hydrogel is an effective means to study the strengthening mechanism of the hydrogel. In this work, a series of acrylonitrile copolymer hydrogels based on crystal microphase crosslinking are synthesized. On this basis, a combined model that consists of the Upper Convected Maxwell model and an ideal spring model is established, which separates the crystal microphase crosslinking network (elastic) from the physical crosslinking network (viscoelastic) based on dipole–dipole interaction. The good fit of the simulated curves to the experimental curves demonstrates that the mechanical behaviors of these hydrogels could be well expressed by such a combined model. The contributions of the two networks to the nominal stress are calculated respectively, and the crosslink densities of the two networks are also compared. It is found that the crosslink density of the viscoelastic network in the hydrogel is higher than that of the elastic network, which further confirms the fact that there is a microphase crosslinking structure in the hydrogel. In addition, the effects of acrylic acid feed ratio, molecular weight and zinc chloride concentration on the network structure of the hydrogel are discussed.

Electrospun poly(ST-Co-AC)/Co-ZIF-67@Chitosan composite nanofibers as a sorbent with superior reusability for pesticide residues analysis in food samples

Pollution caused by pesticides have attracted huge attention, and it is of a great significance to develop sensitive methods for trace monitoring these analytes in complicated matrices. Herein, the composite of styrene acrylonitrile copolymer p(St-Co-AC)/zeolitic based metal–organic frameworks (Co-ZIF-67)/Chitosan (CS) electrospun nanofibers was fabricated by using an electrospinning approach. The resultant composite nanofibers were characterized to apply as a novel adsorbent for pipette tip micro solid-phase extraction (PT- μSPE) of four pesticides prior to GC-FID analysis. Incorporating Co-ZIF-67@Chitosan into p(ST-Co-AC) results in increasing the porosity features and surface area of the nanofibers. The effect of different main parameters on extraction efficiency was evaluated. Under the optimal conditions, linearity ranges were 1.5–2000.0 ng mL−1 for ethofumasate, 2.0–2000.0 ng mL−1 for ametryn and propazine, and 3.0–2000.0 ng mL−1 for tribenuron-methyl (R2 = 0.9951–0.9997). The LODs (according to S/N = 3) were calculated in the range of 0.5 to 1.0 ng mL−1.The relative standard deviations (RSDs) were obtained between 5.1 % – 6.1 % (intra-day, n = 5) and 5.6 %–6.4 % (inter-day, n = 3) for three sequential days. The developed method was investigated in food samples including apple, tomato, honey, and milk, and achieved recoveries (88.1–95.2 %) indicated that the fabricated sorbent could be a promising composite for the pre-concentration of pesticides in various matrices.

An Acrylonitrile-Based Copolymer Gel as an NMR Alignment Medium for Extraction of Residual Dipolar Couplings of Small Molecules in Aqueous Solution.

An NMR weakly-aligning polymer gel has been prepared by copolymerization of acrylonitrile and 2-acrylamide-2-methyl-1-propanesulfonic acid in the presence of 1,4-butanediol diacrylate as a cross-linker. The polymer readily swells in water in a large range of temperatures, although the swelling ratio is decreased in saline solutions. The swollen gel can be mechanically compressed, in a reversible way, generating anisotropy, as easily shown in 2 H NMR experiments, and allowing measurement of 1 DCH residual dipolar couplings (RDCs) through F1-coupled HSQC experiments. The performance of this gel as a NMR alignment medium was evaluated in several water-soluble organic molecules and, while it provided RDCs of proper size for sucrose and even such as small molecule as 5-norbornen-2-ol, in the case of azidothymidine and cefuroxime sodium salt the strong interaction of these molecules with the gel prevented successful extraction of the RDCs.

Properties of acrylonitrile styrene acrylate copolymer modified eucalyptus/polyvinyl chloride composites

Eucalyptus/polyvinyl chloride (PVC) composites were prepared by extrusion molding with eucalyptus as filler, PVC as matrix, and different contents of acrylonitrile styrene acrylate copolymer (ASA). The effects of different ASA content on the mechanical properties, water absorption properties, and thermal stability of eucalyptus/PVC composites were studied. The morphology of the tensile section of the composites was observed by scanning electron microscopy (SEM). The results showed that the addition of ASA could improve the mechanical properties, heat resistance, and interfacial compatibility of eucalyptus/PVC composites. It also could reduce the water absorption of the composites. When ASA content was 10 wt%, the mechanical properties and heat resistance of eucalyptus/PVC composite were the best, and the water absorption in 24 h was the lowest.

Nitrogen-containing multifunctional copolymers as reagents to sorb rare-earth metals

ABSTRACT N,N-Diallyl-N’-neopentanoylhydrazine was for the first time synthesized by the reaction of allylchloride with neopentanoylhydrazine. There was shown a possibility of involving the said monomer into a radical copolymerization reaction with acrylonitrile. The sorption capacity of acrylonitrile copolymers with N,N-diallyl-N’-acetylhydrazine and N,N-diallyl-N’-neopentanoylhydrazine toward light rare earth metal ions – La(+3), Sm(+3) and Ce(+3) – was investigated. The introduction of a neopentanoyl fragment into multifunctional copolymers was evinced to enhance their activity in the sorption processes of lanthanoids. Among the light rare-earth metals studied, samarium is much better extracted. With increasing concentration of sulfuric acid, the sorption capacity of both copolymers toward samarium ions enlarges and equals 150 mg∙g−1. The rate constants of external and internal diffusion within fixed intervals of time were calculated, with an essential role of both external and internal factors in the diffusion processes shown. The results obtained in exploring the conjoint adsorption of La, Ce, and Sm ions by the copolymer based on N,N-diallyl-N’-neopentanoylhydrazine evince a satisfactory separation as being attainable in acidic and alkaline media; at this point, for Cm/Ce ions the distribution coefficient βCm/Ce equals 4.78 at pH 0.3, and 2.5 at pH 11.4; for La/Ce ions it equals 3.39 at pH 0.3 and 2.2 at pH 11.4.

Copolymerization of acrylonitrile with a nitrogen-containing ester

In the paper the results of synthesis of binary copolymers with different contents of monomer units by radical copolymerization of 1-chloro-3-piperidino-2-propylacrylate with acrylonitrile in organic solvent medium at 30-60°C in the presence of radical initiator using free-radical polymerization technique not up to high degrees of transformation by gravimetric method are given. Dinitrilazobisobisobutyric acid was used as the radical initiator. Water and dimethylformamide were used as solvent. Under these conditions in water the process proceeds heterogeneously, and in dimethylformamide homogeneously and with high speed. The synthesis rate of copolymers of 1-chloro-3-piperidino-2-propylacrylate with acrylonitrile in the studied solvents increases with increasing temperature. Experimental studies have shown that copolymerization does not proceed in the absence of the initiator and this indicates a radical nature of the reaction. The structure of synthesized compounds was confirmed by IR, NMR spectral analyses. The participation of multiple bonds of both monomers during copolymerization was determined. The composition of copolymers has been determined which indicates that the copolymer formed at early stages is enriched with 1-chloro-3-piperidino-2- propylacrylate units. The values of relative activities of monomers were calculated by Feinemann-Ross method. The found values of copolymerization constants 7:1=0.28, 7:2=0.62 and the value of product of copolymerization constants less than unity that both types of formed polymer radicals react much faster with foreign monomer than with their own.

Synthesis of a Fiber-Forming Copolymer of Acrylonitrile in Dimethylsulfoxide

Synthesis of a Fiber-Forming Copolymer of Acrylonitrile in Dimethylsulfoxide

Adsorption and photocatalytic degradation of tetracycline from water by kappa‐carrageenan and iron oxide nanoparticle‐filled poly (acrylonitrile‐co‐N‐vinyl pyrrolidone) composite gel

AbstractIron oxide nanoparticles (FeNPs) based magnetic hydrogels were prepared by in‐situ co‐precipitation of ferric/ferrous salts during copolymerization of acrylonitrile (AN) and N‐vinyl‐2‐pyrrolidone (NVP) at different molar ratios by emulsion polymerization in the presence of different wt% of kappa‐carrageenan (KC) and N, N′‐methylenebisacrylamide (MBA)crosslinker. The hydrogels were characterized by FTIR, proton and13C‐NMR, XPS, XRD, DTA‐TGA, DLS, VSM, UV–Visible spectroscopy, TEM, EDX, PZC, compressive strength and contact angle measurement. The network parameters of the gel networks were determined from equilibrium swelling using Flory and Rehner model. The nanocomposite gels were used for batch and column adsorption of tetracycline (TC) from water. After repeated adsorptions, the TC‐loaded gels were further used for their photocatalytic degradation for safe removal. The NPs‐loaded nanocomposite prepared with 5:1 AN:NVP molar ratio, 1 wt% initiator, 1 wt% MBA and 2 wt% KC showed a rejection of 90.2% and an equilibrium adsorption capacity of 38.9 mg/g for continuous adsorption of 50 mg/L TCs in water in a fixed bed of height 25 mm for an inflow rate of 20 ml/min and the same TC‐loaded composite showed a photo‐degradation efficiency of 86.1% in 2 h.