Search Results (39)

A novel mesoporous spherical chelating lignin-based adsorbent was successfully synthesized via inverse suspension polymerization using sulfate pine pulping black liquor as raw material, followed by graft copolymerization with acrylonitrile and subsequent amination. The obtained aminated cyanoethyl spherical lignin resin (ACSLR) exhibited a well-defined porous morphology and abundant active sites, as confirmed by SEM and FT-IR. Adsorption experiments demonstrated high Pb²⁺ uptake capacity (63.98 mg·g⁻¹) under optimal conditions (pH = 5.5, 2.0 g·L⁻¹ adsorbent dosage, and 150 mg·L⁻¹ initial concentration of Pb²⁺ solution). The adsorption process followed the Langmuir isotherm and pseudo-second-order kinetics, indicating monolayer chemisorption dominated by amino and cyano groups. This work provides a sustainable strategy for valorizing industrial lignin waste into efficient adsorbents for heavy metal removal, highlighting its potential for practical wastewater treatment applications. Full article

In the work presented here, we explore the upcycling of polyethylene terephthalate (PET) that was derived from water bottles. The material was granulated and extruded into a filament compatible with fused filament fabrication (FFF) additive manufacturing platforms. Three iterations of PET combined with a thermoplastic elastomer, styrene ethylene butylene styrene with a maleic anhydride graft (SEBS-g-MA), were made with 5, 10, and 20% by mass elastomer content. The elastomer and specific mass percentages were chosen based on prior successes involving acrylonitrile butadiene styrene (ABS), in which the maleic anhydride graft enabled compatibility between different materials. The rheological properties of PET and the PET/SEBS blends were characterized by the melt flow index and dynamic mechanical analysis. The addition of SEBS-g-MA did not have a significant impact on mechanical properties, as determined by tensile and impact testing, where all test specimens were manufactured by FFF. Delamination of the tensile specimens convoluted the ability to discern differences in the mechanical properties, particularly % elongation. Annealing of the specimens enabled the observation of the effect of elastomer content on the mechanical properties, particularly in the case of impact testing, where the impact strength increased with the increase in SEBS content. However, annealing led to shrinkage of the specimens, detracting from the realized benefits of the thermal process. Scanning electron microscopy of spent tensile specimens revealed that, in the non-annealed condition, SEBS formed nodules that would detach from the PET matrix during the tensile test, indicating that a robust bond was not present. The addition of SEBS-g-MA did allow for shape memory property characterization, where deformation of tensile specimens occurred at room temperature. Specimens from the 20% by mass elastomer content sample group exhibited a shape fixation ratio on the order of 99% and a shape recovery ratio on the order of 80%. This work demonstrates a potential waste reduction strategy to tackle the problem of polymer waste by upcycling discarded plastic into a feedstock material for additive manufacturing with shape memory properties. Full article

Despite polycarbonate (PC) being a widely used engineering plastic, its notch and crack sensitivity pose challenges in critical applications. To address this, PC was blended with elastomeric polymers to explore the improvement in toughness. This study systematically investigates the toughening mechanisms of PC blended with acrylonitrile–butadiene–styrene (ABS), copolyether ester elastomer (COPE), and ABS and styrene–ethylene–butylene–styrene (SEBS) copolymer grafted with maleic anhydride (MA). The morphology and mechanical behavior were evaluated under quasi-static and medium-strain-rate tensile tests and Charpy impact tests using optical, electronic, and atomic force microscopy and Raman mapping spectroscopy. The morphological analysis reveals cavitation and crazing phenomena for COPE and SEBS-g-MA systems, and mostly debonding for ABS, indicating an improvement in toughening. While the addition of ABS improves the PC plastic deformation, modifying ABS with maleic anhydride enhances the elastic modulus. Blending PC with SEBS-g-MA increases the strain at break, and the addition of COPE significantly improves the deformation behavior of PC (by around 115%). This comparative study provides valuable insights into the performance of different PC–elastomer blends under similar conditions, supporting the selection of appropriate materials for given applications. Full article

This study investigated the sustainable toughening of polylactic acid (PLA) by incorporating ultrafine fully vulcanized powdered natural rubber graft-copolymerized with poly-styrene-co-acrylonitrile (UFPNR-SAN). We investigated the effect of the styrene-to-acrylonitrile ratio (ST:AN) used during the grafting process on the final UFPNR-SAN compatibility with PLA. The ST:AN ratio was systematically varied during the grafting reaction to prepare UFPNR-SAN with a range of different surface energies. The ST:AN ratio of 4:1 showed the highest compatibility with the PLA matrix, attributed to optimal interfacial interactions and improved dispersion, as indicated by contact angle measurements and SEM observations. This resulted in a remarkable toughening of the PLA/UFPNR-SAN composite. For instance, an obvious fully ductile behavior without crack formation and flexural strain of around 17.5% against 5% of the neat PLA was recorded. In addition, 3.5 times improvement in the impact strength of the composite at 25 wt% dosage of the UFPNR-SAN was also achieved without compromising thermal properties. Overall, this study established the suitable ST:AN ratio on the grafting onto natural rubber to enhance interfacial interactions with PLA and its effects on the properties of the resulting PLA/UFPNR-SAN bio-based composite. Full article

A highly efficient low-cost adsorbent was prepared using raw and chemically modified cellulose isolated from sugarcane bagasse for decontamination of Cr(VI) from wastewater. First, cellulose pulp was isolated from sugarcane bagasse by subjecting it to acid hydrolysis, alkaline hydrolysis and bleaching with sodium chlorate (NaClO₃). Then, the bleached cellulose pulp was chemically modified with acrylonitrile monomer in the presence Fenton’s reagent (Fe⁺²/H₂O₂) to carry out grafting of acrylonitrile onto cellulose by atom transfer radical polymerization. The developed adsorbent (acrylonitrile grafted cellulose) was analyzed by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Both raw cellulose and acrylonitrile grafted cellulose were used for chromium removal from wastewater. The effects of metal ion concentration, pH, adsorbent dose and time were studied, and their values were optimized. The optimum conditions for the adsorption of Cr(VI) onto raw and chemically modified cellulose were: metal ion concentration: 50 ppm, adsorbent dose: 1 g, pH: 6, and time: 60 min. The maximum efficiencies of 73% and 94% and adsorption capacities of 125.95 mg/g and 267.93 mg/g were achieved for raw and acrylonitrile grafted cellulose, respectively. High removal efficiency was achieved, owing to high surface area of 79.92 m²/g and functional active binding cites on grafted cellulose. Isotherm and kinetics studies show that the experimental data were fully fitted by the Freundlich isotherm model and pseudo first-order model. The adsorbent (acrylonitrile grafted cellulose) was regenerated using three different types of regenerating reagents and reused thirty times, and there was negligible decrease (19%) in removal efficiency after using it for 30 times. Hence, it is anticipated that acrylonitrile could be utilized as potential candidate material for commercial scale Cr(VI) removal from wastewater. Full article

The high elasticity and excellent gas barrier properties of rubber composites make them irreplaceable in the field of sealing. Constructing a complicated barrier network to reduce free volume is crucial to improving gas barrier properties. In this research, liquid acrylonitrile-butadiene rubber/γ-Methacryloxypropyl trimethoxy silane (KH570) modified graphene oxide/butyl rubber composites (LNBR/KGO/IIR) were fabricated. A KGO lamellar network was constructed to resist gas diffusion in the IIR matrix. Meanwhile, LNBR macromolecules further occupied the free volume inside the IIR composites, thereby maximizing the retardation of the path of small molecule gas permeation. The modification of GO by KH570 was successfully demonstrated through FTIR and XRD. The grafting rate of KH570 was calculated to be approximately 71.4%. KGO was well dispersed in IIR due to emulsion compounding and the formation of lamellar networks. The 300% modulus, tensile strength and tear strength of KGO/IIR were improved by 43.5%, 39.1% and 14.8%, respectively, compared to those of the IIR composite. In addition, the introduction of LNBR resulted in a 44.2% improvement in the gas barrier performance of nitrogen permeability relative to the original IIR composite. Full article

In this study, the synthesis and characterization of grafted cellulose fiber with binary monomers mixture obtained using a KMnO₄/citric acid redox initiator were investigated. Acrylonitrile (AN) was graft copolymerized with acrylic acid (AA) and styrene (Sty) at different monomer ratios with evaluating percent graft yield (GY%). Cell-g-P(AN-co-AA) and Cell-g-P(AN-co-Sty) were characterized by SEM, FT-IR, ¹³C CP MAS NMR, TGA, and XRD. An AN monomer was used as principle-acceptor monomer, and GY% increases with AN ratio up to 60% of total monomers mixture volume. The adsorption behaviors of Cell-g-P(AN-co-AA) and Cell-g-P(AN-co-Sty) were studied for the adsorption of Ni(II) and Cu(II) metal ions from aqueous solution. Optimal adsorption conditions were determined, including 8 h contact time, temperature of 30 °C, and pH 5.5. Cell-g-P(AN-co-AA) showed maximum adsorption capacity of 435.07 mg/g and 375.48 mg/g for Ni(II) and Cu(II), respectively, whereas Cell-g-P(AN-co-Sty) showed a maximum adsorption capacity of 379.2 mg/g and 349.68 mg/g for Ni(II) and Cu(II), respectively. Additionally, adsorption equilibrium isotherms were studied, and the results were consistent with the Langmuir model. The Langmuir model’s high determinant coefficient (R²) predicted monolayer sorption of metal ions. Consequently, Cell-g-P(AN-co-AA) and Cell-g-P(AN-co-Sty) prepared by a KMnO₄/citric acid initiator were found to be efficient adsorbents for heavy metals from wastewater as an affordable and adequate alternative. Full article

In this work, blends based on poly (lactic acid) (PLA)/acrylonitrile-butadiene-styrene (ABS) compatibilized with maleic anhydride-grafted (SEBS-g-MA) were prepared in a co-rotational twin-screw extruder by varying the concentrations of the compatibilizing agent. The influence of the compatibilizing agent on the morphology, mechanical, thermal, thermomechanical, and rheological properties of the prepared materials was analyzed. The effect of annealing on the properties of the blends was also investigated using injection-molded samples. The X-ray diffraction (XRD) results proved that the increments in crystallinity were an effect of annealing in the PLA/ABS/SEBS-g-MA blends, resonating at higher heat deflection temperatures (HDTs). The impact strength of the PLA/ABS blends compatibilized with 10 wt% SEBS-g-MA was significantly increased when compared to the PLA/ABS blends. However, the hardness and elastic modulus of the blends decreased when compared to neat PLA. The refined morphology shown in the scanning electron microscopy (SEM) analyses corroborated the improved impact strength promoted by SEBS-g-MA. The torque rheometer degradation study also supported the increased compatibility between SEBS-g-MA, PLA, and ABS. The TGA results show that the PLA/ABS and PLA/ABS/SEBS-g-MA blends are more thermally stable than the neat PLA polymer at higher temperatures. The results showed that the ideal composition is the heat-treated PLA/ABS/SEBS-g-MA (60/30/10 wt%), given the high impact strength and HDT results. The results of this work in terms of mechanical improvement with the use of compatibilizers and annealing suggest that the PLA/ABS/SEBS-g-MA system can be used in the production of 3D-printing filaments. Full article

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. Full article

The water absorption measurements of a novel superabsorbent anionic hydrogel, H-Na-PCMSA-g-PAN, has been reported first time in water with a poor conductivity, 0.15 M saline (NaCl, CaCl_2, and AlCl₃) solutions, and simulated urine (SU) solutions at various times. The hydrogel has been prepared by the saponification of the graft copolymer, Na-PCMSA-g-PAN (%G = 316.53, %GE = 99.31). Results indicated that as compared to the swelling capacity values evaluated in water with a poor conductivity, the ability of the hydrogel to swell in various saline solutions with the same concentration is significantly reduced at all different durations. The swelling tends to be Na⁺ > Ca²⁺ > Al³⁺ at the same saline concentration in the solution. Studies of the absorbency in various aqueous saline (NaCl) solutions also revealed that the swelling capacity decreased as the ionic strength of the swelling medium rose, which is consistent with the experimental results and Flory’s equation. Furthermore, the experimental results strongly suggested that second-order kinetics governs the swelling process of the hydrogel in various swelling media. The swelling characteristics and equilibrium water contents for the hydrogel in various swelling media have also been researched. The hydrogel samples have been successfully characterized by FTIR to show the change in chemical environment to COO⁻ and CONH₂ groups after swelling in different swelling media. The samples have also been characterized by SEM technique. Full article

A systematic study was performed to provide better understanding of the effect of elastomeric materials on the behavior of polycarbonate blends (PC). Thus, blends of PC with different amounts of elastomers, such as copolyether ester elastomer (COPE), acrylonitrile–butadiene–styrene (ABS), maleic anhydride-grafted ABS (ABS-g-MA), and styrene–ethylene–butylene–styrene (SEBS-g-MA) were prepared in a co-rotating twin-screw extruder. The materials were characterized by an electronic microscopy (SEM), an infrared spectroscopy (FTIR), and thermal (DSC) and thermo-mechanical (DMA) techniques. The incorporation of elastomeric phases was observed by changes in the FTIR band’s intensity, whereas a new shoulder of the ester band of COPE at 1728 cm⁻¹ indicates the occurrence of a transesterification reaction. Unmodified and modified ABS (5% and 10%) did not affect the glass transition temperature (T_g) of PC, while 1% SEBS-g-MA slightly increased this value. PC/10% COPE showed that a decrease in T_g of 25 °C has a result of better compatibilization between both phases, which is visible via SEM. SEM analysis identified three main toughening mechanisms, depending on the type of elastomer. Unlike any other study, this work deepens the knowledge, in a comparative way, to understand the elastomeric effect at the interface and consequently, on the mechanical behavior of PC systems. Full article

Graft copolymerization has been a popular technique in recent years for adding different functional groups to polymers. In our research, polypropylene (PP) films are grafted with acrylonitrile (An) and acrylic acid (AAc) monomers to make them hydrophilic while retaining their mechanical qualities. Gamma radiation is used in this approach to establish active spots on an inert polymer that are appropriate for adding monomers radicals to form grafts, a procedure that is extremely difficult to perform using normal chemical processes. The graft parameters are investigated in order to acquire the highest percentage of graft. FTIR (Fourier transform infrared spectroscopy) spectra are used to analyze the grafting of AAc and An. SEM (scanning electron microscopy) and XRD (X-ray diffraction) micrographs are used to validate them. The specimens’ tensile strength and hardness are measured and contrasted with blank PP films. Measurements are made of the effects of grafting on the tensile strength and elongation of the films, and a crucial grafting degree is established in order to preserve these properties. Water uptake is measured to adapt the copolymer to water treatment, and thermal behavior TGA (thermal gravimetric analysis) and DSC (diffraction scanning calorimeter) of the produced copolymer were performed. The elimination of cadmium was verified by an atomic absorption spectrophotometer (AAS) under different conditions of pH, time, and degree of grafting. Full article

Aramid nanofibers (ANFs) were successfully produced by deprotonation of Kevlar fiber followed by grafting epichlorohydrin in dimethyl sulfoxide solution. The ANFs were then incorporated into carboxylated acrylonitrile butadiene rubber (XNBR) by means of latex blending, followed by vulcanization. The interaction between ANFs and XNBR, and the effects of ANFs on the mechanical strength, dielectric properties, and thermal stability of ANF/XNBR nanocomposites were investigated. The results revealed that hydrogen bonding and covalent bonding interactions existed between ANFs and the XNBR matrix and played a critical role in the reinforcement of ANFs to XNBR nanocomposites. After adding 5 phr (parts per hundred rubber) of ANFs, the XNBR nanocomposite exhibited a significant improvement in mechanical properties, namely a 182% increase in tensile strength and a 101% increase in tear strength. In addition, the dielectric constant and thermal properties of ANF/XNBR also increased dramatically. ANFs may thus make an ideal candidate for high-performance rubber materials. Full article

Polypropylene (PP)/acrylonitrile butadiene rubber (NBR) composite plates reinforced with halloysite nanotubes (HNTs) were manufactured in the presence of dual compatibilizers: PP-grafted maleic anhydride (PP-g-MA) and styrene ethylene butylene styrene-grafted maleic anhydride (SEBS-g-MA). The mechanical characteristics and microstructure of the PP/NBR/HNT nanocomposites were investigated as a function of NBR content (10, 20, and 30 wt.%) and HNTs content (3, 5, and 7 wt.%). The results demonstrated that the rubber particles were well dispersed over the PP matrix and that the HNTs were partly agglomerated at contents above 5%. Friction stir welding (FSW) was used to join the nanocomposite plates. A significant reduction in scattered NBR droplet size was seen in the FS-welded specimens containing 80/20 (wt/wt) PP/NBR composites in the presence of a dual compatibilizer. Considerable improvement in particle dispersion was observed in the case of PP/NBR blends filled 80/20 (wt/wt) with HNTs joined using FSW, leading to enhanced mechanical properties in the joints. This was due to the stirring action of the FSW tool. Suitable agreement between anticipated and confirmed values was observed in experiments. Full article

The synthesis of hydrogel beads involving natural polymers is, nowadays, a leading research area. Among natural polymers, starch and chitosan represent two biomolecules with proof of efficiency and low economic impact in various utilization fields. Therefore, herein, the features of hydrogel beads obtained from chitosan and three sorts of starch (potato, wheat and rise starches), grafted with acrylonitrile and then amidoximated, were deeply investigated for their use as sorbents for heavy metal ions and dyes. The hydrogel beads were prepared by ionotropic gelation/covalent cross-linking of chitosan and functionalized starches. The chemical structure of the hydrogel beads was analyzed by FT-IR spectroscopy; their morphology was revealed by optical and scanning electron microscopies, while the influence of the starch functionalization strategies on the crystallinity changes was evaluated by X-ray diffraction. Molecular dynamics simulations were used to reveal the influence of the grafting reactions and grafted structure on the starch conformation in solution and their interactions with chitosan. The sorption capacity of the hydrogel beads was tested in batch experiments, as a function of the beads’ features (synthesis protocol, starch sort) and simulated polluted water, which included heavy metal ions (Cu²⁺, Co²⁺, Ni²⁺ and Zn²⁺) and small organic molecules (Direct Blue 15 and Congo red). Full article