Commercial Acrylic Fibers Research Articles

A Universal Polyiodide Regulation Using Quaternization Engineering toward High Value-Added and Ultra-Stable Zinc-Iodine Batteries.

The development of aqueous rechargeable zinc‐iodine (Zn‐I2) batteries is still plagued by the polyiodide shuttle issue, which frequently causes batteries to have inadequate cycle lifetimes. In this study, quaternization engineering based on the concept of “electric double layer” is developed on a commercial acrylic fiber skeleton ($1.55–1.7 kg−1) to precisely constrain the polyiodide and enhance the cycling durability of Zn‐I2 batteries. Consequently, a high‐rate (1 C–146.1 mAh g−1, 10 C–133.8 mAh g−1) as well as, ultra‐stable (2000 cycles at 20 C with 97.24% capacity retention) polymer‐based Zn‐I2 battery is reported. These traits are derived from the strong electrostatic interaction generated by quaternization engineering, which significantly eliminates the polyiodide shuttle issue and simultaneously realizes peculiar solution‐based iodine chemistry (I−/I3 −) in Zn‐I2 batteries. The quaternization strategy also presents high practicability, reliability, and extensibility in various complicated environments. In particular, cutting‐edge Zn‐I2 batteries based on the concept of derivative material (commercially available quaternized resin) demonstrate ≈100% capacity retention over 17 000 cycles at 20 C. This work provides a general and fresh insight into the design and development of large‐scale, low‐cost, and high‐performance zinc‐iodine batteries, as well as, other novel iodine storage systems.

Thermal Analysis of Fibers

Abstract Conducting thermal analysis of fibers in the swollen state possesses certain characteristics and advantages. The thermograms including both TMA and DSC of 12 acrylic fiber samples of different composition and mode of formation are given in this part of the paper. The lowering of the transition temperature as a depression of the melting points according to the theory of Flory is tested. The DSC thermograms of a commercial acrylic fiber sample are separated into its constituent peaks and the bond energy of the four regions is calculated. Finally the relation of the magnitudes of the different peak of a PAC Abbreviation of polyacrylonitrile copolymer. ) fiber sample is sought and the effects of annealing and hot stretching of acrylic fibers on its texture are demonstrated.

Citric acid-modified acrylic micro and nanofibers for removal of heavy metal ions from aqueous media

AbstractThe present work describes a new modification process for producing chelating fibers for removal of heavy metal ions from aqueous solutions. Commercial acrylic fibers were hydrolyzed with sodium hydroxide to convert the CN groups on the molecular chains of the polymer to carboxylic acid groups. To increase the density of carboxyl groups on the fibers surface, citric acid was grafted to carboxylic acid groups. Furthermore, for comparison of the effect of surface area on the adsorption capacity, modified fibers were electrospun and the ability of both modified micro and nanofibers for the removal of Cu2+ and Ni2+ ions from aqueous media was evaluated. The chemical and morphological modifications of the fibers were evaluated using ATR-FTIR, thermo gravimetric analysis, and scanning electron microscopy. ATR-FTIR spectra showed reduction in the intensity of CN stretching vibrations and creation of carboxylic groups on the fibers surface. Atomic absorption spectroscopy was used to determine the ability ...

Synthesis and characterization of acrylic fibers-g-polyacrylamide

Graft copolymerization of acrylamide onto commercial acrylic fibers was carried out using benzoyl peroxide as a free-radical initiator in aqueous medium within the 75–95 °C temperature range. In this study, the effects of initiator and monomer concentration, the amount of fiber, polymerization time, and temperature on the graft yield were investigated. The optimum concentration for initiator was found to be 2.0×10−3 mol/l and the optimum temperature of 85 °C. The activation energy of the reaction was calculated to as 35.81 kJ/mol at the temperature interval of 75–95 °C. The structures and morphologies characterization of grafted fibers was investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The thermogravimetric analysis data showed that the thermal stability of the acrylic fibers increased with graft yield. The scanning electron photographs showed that the homogeneous appearance of the fiber surface changed and a shell-like heterogeneous structure occurred at the surface with an increasing degree of grafting. The moisture content, water absorption, dyeability, and antimicrobial activity of grafted acrylic fibers were also reported. The results showed that grafting of polyAAm improved the moisture contain, water absorption, dyeability, and antimicrobial activity of fiber.

Fabrication of chelating diethylenetriaminated pan micro and nano fibers for heavy metal removal

In this study, commercial acrylic fibers were modified with diethylenetriamine to prepare metal chelating fibers. The effects of process parameters on the efficiency of the reaction were investigated. FTIR spectroscopy and TGA analysis were used to confirm the chemical changes made to the fibers during the reaction. The ability of the modified fibers for removal of Pb (II), Cu (II) and Ce (IV) ions from aqueous media was determined. The modified fibers showed a slight decrease in mechanical properties compared to raw ones. Furthermore, the acrylic micro fibers were electrospun to nanofibers and the ability of modified nanofibers for the adsorption of the metal ions was studied.

Characterization and modification of commercial acrylic fibers grafted with acrylic acid

AbstractThe graft copolymerization of acrylic acid (AA) onto commercial acrylic fibers (PAN) has been studied using Azobis(isobutyro)nitrile (AIBN) as an initiator. AA grafting initiated by radicals formed from thermal decomposition of AIBN. In this study, the effects of monomer and initiator concentration, time and temperature reaction on the grafting yield have been investigated. The optimum conditions for this grafting reaction were obtained with an AA concentration of 1.67 M, an AIBN concentration of 0.0097 M, a reaction temperature of T=85 °C and with reaction time of 60 minutes.The fiber structure has been investigated by different experimental techniques of characterization such as Fourier transform infrared spectroscopy (FT‐IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), water absorption and also in this study has been investigated the mechanical property. The thermal analysis data showed that increasing in grafting yield, decreases the thermal stability of fiber. Grafting also affected slightly the fiber morphology. The experimental data of mechanical properties show clearly that by increasing of grafting yield, max extension will decrease. Grafting of poly AA improved water absorption.

Characterization and Studies on Grafting of Methyl Methacrylate onto PAN Fibers

The graft copolymerization of methyl methacrylate (MMA) onto commercial acrylic fibers (PAN) has been studied using Azobis(isobutyro)nitrile (AIBN) as an initiator. MMA grafting initiated by radicals formed from thermal decomposition of AIBN. In this study, the effects of monomer and initiator concentration, time and temperature reaction on the grafting yield have been investigated. The optimum conditions for this grafting reaction were obtained with an MMA concentration of 0.7 M, an AIBN concentration of 0.0073 M, a reaction temperature of T=85°C and with a 60 min reaction time. The fiber structure has been investigated by different experimental techniques of characterization such as Fourier transform infrared spectroscopy (FT‐IR), calorimetric analysis (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), water absorption and the physical and mechanical properties has also been investigated in this study. The thermal analysis data showed that by increasing grafting yield, little changes have occurred in fibers samples up to 13.5% of grafting yield and the thermal transitions of grafted fibers have approximately the same behavior compared with the raw fibers sample. Grafting also slightly affected the fiber morphology. The experimental data of mechanical properties clearly show that by increasing grafting yield, max extension will decrease but this change up to 13.5% grafting yield is barely noticeable. Grafting of poly MMA improved water absorption.

Production of activated carbon cloth with controlled structure and porosity from a new precursor

The production of micro and mesoporous activated carbon cloth (ACC) from commercial acrylic textile fibres by physical activation with carbon dioxide and the addition of boric acid and sodium hydrogen phosphate as impregnants is reported. The use of sodium hydrogen phosphate leads to samples with greater mesopore volume whereas other ACC production conditions studied mainly result in microporous materials. This work demonstrates that it is possible to produce carbon materials from a commercial acrylic textile cloth with the maintenance of the precursor shape, as shown by scanning electron microscopy (SEM). The materials are formed from layers of aromatic sheets that in a nanoscale resemble graphite and X-ray diffraction studies indicate microcrystallites with dimensions between 5.9 and 7.6 nm for L a (width) and between 2.4 and 2.7 nm for L c (height), corresponding to 7 to 8 parallel graphene layers.

Effect of thermal characteristics of commercial and special polyacrylonitrile fibres on the fabrication of carbon fibres

Carbon fibres are still expensive. Although in recent years, many attempts have been made to use commercial polyacrylonitrile (PAN) fibres instead of special PAN fibres as a carbon fibre precursor in order to reduce price, this replacement shows some difficulties in processing and properties of final carbon fibres. In the present research, thermal properties of commercial and special PAN fibres are investigated by thermal analysis methods such as differential scanning calorimetry and thermogravimetric analysis in order to find the effect of chemical composition and characterisation of these precursors on stabilisation conditions and properties of resultant carbon fibres. Results show that the type of comonomers used in acrylic fibres changes the stabilisation conditions. Addition of sodium 2-methyl-2-acrylamidopropane sulphonate (SAMPS) and sodium methallyl sulphonate (SMS) comonomers to improve dyeability of commercial acrylic fibres will increase cyclisation reaction initiation and stabilisation temperature, but the effect of SAMPS in this respect is more harmful and the presence of SAMPS produces carbon fibres with lower tensile strength. On the other hand, addition of itaconic acid comonomer decreases cyclisation reaction initiation and stabilisation temperatures and finally gives carbon fibres desirable properties.

A novel fiber‐coated strong base‐type anion exchanger with superfast kinetics. Removal and recovery of silver thiosulfate from aqueous solutions

AbstractA commercial acrylic fiber with 92% (w/w) acrylonitrile content was partially hydrolyzed converting a fraction of the nitrile (CN) groups to carboxylic acid (COOH) groups, to coat the fiber with polyethylenimine (PEI) resin, which was then crosslinked with glutaraldehyde and further quaternized with ethyl chloroacetate to produce a novel strong‐base anionic exchanger in the form of fiber. Designated as PAN(QPEI.XG)(Cl−), the fibrous sorbent was compared with a commercial bead‐form resin Amberlite IRA‐458(Cl−) in respect of sorption capacity, selectivity, and kinetics for removal of silver thiosulfate complexes from aqueous solutions. Though the saturation level of [Ag(S2O3)2]3− on PAN(QPEI.XG)(Cl−) is considerably less than that on IRA‐458(Cl−), the gel‐coated fibrous sorbent exhibits, as compared to the bead‐form sorbent, a significantly higher sorption selectivity for the silver thiosulfate complex in the presence of excess of other anions such as S2O32−, SO42−, and Cl−, and a remarkably faster rate of both sorption and stripping. The initial uptake of the sorbate by the fibrous sorbent is nearly instantaneous, reaching up to ∼80% of the saturation capacity within 10 s, as compared to only ∼12% on the bead‐form sorbent. The high initial rate of uptake fits a shell‐core kinetic model for sorption on fiber of cylindrical geometry. With 4M HCl, the stripping of the sorbed silver complex from the fibrous sorbent is clean and nearly instantaneous, while, in contrast, a much slower rate of stripping on the bead‐form sorbent leads to its fouling due to a slow decomposition of the silver thiosulfate complex in the acidic medium. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2604–2613, 2006

From commercial textile fibres to activated carbon fibres: Chemical transformations

The production of activated carbon fibres from commercial acrylic textile fibres was analysed in order to study the chemical transformations suffered by the precursor during the process. The thermal degradation of the precursor polymeric chain starts with the cyclisation of the structure with acetate ion from vinyl acetate acting as a catalyst. The chemical transformations continue with both cyclisation and dehydrogenation reactions which result in the formation of several functional groups. The groups identified for the carbonised fibre by FTIR were amines, amides, imides, lactones and –OH, whereas for the activated carbon fibre the groups that can be identified were pyrones, lactones, amines, amides and OH.

Ethoxylated polyethylenimine gel‐coated on textile‐grade acrylic fiber. A thermally regenerable superfast sorbent for water desalination

AbstractA commercial acrylic fiber containing 92 wt % acrylonitrile was hydrolyzed to convert a part of its nitrile (CN) groups to carboxylic acid (COOH) groups and then was coated chemically with 80% ethoxylated polyethylenimine (EPEI) resin, followed by crosslinking with glutaraldehyde. The resulting sorbent, PAN(CO2H)(EPEI.XG), containing carboxylic acid groups and weakly basic tertiary amine groups in close proximity on the same fiber is found to simulate the well‐known Sirotherm™ resins used for partial desalination of brine solution by adsorbing the salt at ambient temperature and desorbing it at an elevated temperature in the same solution. The sorption behavior of the new sorbent was evaluated for solutes NaCl and MgCl2, showing saturation capacities of 0.797 and 0.877 meq/g (dry) sorbent fiber, respectively, at 30°C. The equilibrium sorption data show good agreement with both Langmuir and Freundlich isotherms for sorption from single‐component solutions and with Butler–Ockrent and LeVan–Vermeulen models for bicomponent sorption. Although the equilibrium uptake of NaCl reaches maximum in neutral solutions (pH ∼ 6.5), falling at both lower and higher pH, that of MgCl2 is augmented in alkaline pH due to additional sorption by cation exchange at the ionic sites formed at higher pH. The initial uptake of the salt, which is nearly instantaneous, exceeds the sorption value attainable at equilibrium. The high initial rate of salt uptake fits a shell‐core kinetic model for sorption on fiber of cylindrical geometry. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 883–893, 2004

Scanning electron microscopy of activated carbons prepared from commercial acrylic textile fibres

Scanning electron microscopy has been used to study the variation in surface texture and dimension during carbonisation and activation of three acrylic textile fibres. The results show that both ordered and disorganised forms of carbon exert a direct influence on the macroscopic structure of the carbon materials. In addition, the results also show that the presence of small amounts of an inorganic additive, namely titanium dioxide, can disrupt the graphene structure and lead to modification of the surface texture and reactivity of the carbon materials.

Investigation of molecular orientation in melt-spun high acrylonitrile fibers

The orientation and crystal size of a series of melt-spun high acrylonitrile AMLON® and solution-spun commercial acrylic fibers are investigated by optical and X-ray diffraction analysis. The effect of different processing steps is examined. The image intensity of a birefringent fiber under cross polarizers is fitted accurately, assuming that the birefringence across the entire fiber cross-section is uniform. The molecular orientational order parameter of the fiber, as measured by X-ray diffraction, correlates linearly with its birefringence. The orientation of the melt-spun fibers is as good or better than that of commercial solution-spun fibers, and it increases dramatically in the melt-spun fibers when they are post drawn or spun from higher molecular weight resins. Orientation is affected only slightly by annealing processes, which in turn increase the crystal size in the fiber.

Fractal Ferromagnetic Exchange Interactions in Metal-Containing (Nanosize Clusters) Poly-Conjugated Systems

Abstract Polymers of acrylonitrile, Mtilon (Mt) - cyanoethylated cellulose hydrate [(C6H7O2 )3-x (OCH2CH2CN) x and Nitron (Nt) - commercial acrylic fiber containing 10–60% carboxylic groups have been specially prepared and modified by various metals (Fe, Co, Ni). Subsequent special thermal treatment yielded polymers containing metal nanosize clusters (40–200 A) dispersed in the polymer matrix whose ferromagnetic properties has been thoroughly studied. The chief reasons hindering the creation of high-Tc molecular/polymer-based ferromagnets are determined and analyzed. The concept of fractal ferromagnetic exchange interaction between magnetic moments of neighboring nanosize metal clusters via polyconjugated system is proposed. A new effect of an increase in the specific saturation magnetization μs of metal atoms in clusters is reported. The effect is explained by the spin polarization of the polyconjugated matrix coating the metal clusters, somewhat similar to the chemical polarization of spins of electrons...

Micromorphology Differences between Relaxed and Retractile Acrylic Fibres Subjected to Different Bulking Treatments

Three commercial acrylic fibres from different manufacturers were employed in preparing 100% relaxed (N), 100% retractile (R), 45% N/55% R, and 55% N/45% R substrates. These were subjected to different bulking treatments (boiling water for periods of 15, 30, and 90 min and dry heat). The resulting substrates were tested for differential solubility in a blend of dimethylforamide/water to study their micromorphological evolution.

Thermal Analysis of Fibers

Abstract Conducting thermal analysis of fibers in the swollen state possesses certain characteristics and advantages. The thermograms including both TMA and DSC of 12 acrylic fiber samples of different composition and mode of formation are given in this part of the paper. The lowering of the transition temperature as a depression of the melting points according to the theory of Flory is tested. The DSC thermograms of a commercial acrylic fiber sample are separated into its constituent peaks and the bond energy of the four regions is calculated. Finally the relation of the magnitudes of the different peak of a PAC1) fiber sample is sought and the effects of annealing and hot stretching of acrylic fibers on its texture are demonstrated.

Residual solvent and its diffusion in acrylic fibers

AbstractA survey showed that some commercial acrylic fiber products contain small quantities of residual solvent (dimethylacetamide). No diffusion of solvent from these products could be detected on laundering, dry cleaning, or exposure to synthetic perspiration. Acrylic carpets containing residual solvent were enclosed in sealed boxes to simulate a closed room. Air in the boxes was monitored for solvent content over a 14‐day period at 24°C (75°F) and 38°C (100°F) at both low and high humidity conditions. In all cases the solvent content of the air was below the detection limit of the best analytical procedure available (below 0.1 ppm). Diffusion rates of sol vent from 15‐denier carpel fiber into nitrogen were measured over the temperature range of 25–100°C. There was no detectable diffusion below 60°C measured over a 24‐h period. Mass diffusivities ranged from 2.5 × 10−19 cm2/s at 60°C to 6.4 × 10−14 cm2/s at 100°C. Under the conditions of expected use, the rate of diffusion of residual solvent from acrylic fibers is very low. Based on the low concentrations of residual solvent and its very low diffusion rate, there is an extremely low probability of any exposure to solvent from the residual solvent present in commercial acrylic fiber products.

Influence of drawing and molecular weight on structural‐mechanical properties of acrylic fibers

AbstractThe influence of drawing and molecular weight in a narrow range on the several structural‐mechanical properties of acrylic fibers have been investigated. Drawing of fibers (λ = 3x–6,5x) leads to a considerable increase of tenacity. These data were explained with the orientation and perfection of structure. It was found that the molecular weight in closer range influences the density, perfection of structure, and the stability of fibers to repetitive deformation. The results show that the diversions of the average molecular weight, in the manufacture of commercial acrylic fibers, must be negligible.

Vinyl Polymerization. 287. Polymerization of Methyl Methacrylate Initiated by the Polyacrylonitrile-Water-Cupric Ion System

Abstract Methyl methacrylate was found to be polymerized by the system polyacrylonitrile-water-cupric ion without any added initiator. Addition of carbon tetrachloride to this system greatly increased the polymerization rate. Acrylonitrile and styrene did not polymerize in this system. The kinetic behavior of polymerization was the same as the system consisting'of cellulose or nylon instead of polyacrylonitrile. When the flaky polyacrylo-nitrile was swelled or dissolved by the solvent DMF, the conversion and the degree of polymerization of the poly-methyl methacrylate formed decreased markedly. Commercial acrylic fiber also initiated polymerization but the activity was lower than with flaky polyacrylonitrile, even after steam treatment, because of the poor permeability of monomer into the fiber.