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Enhancing interfacial adhesion in polypropylene (PP)/recycled polyethylene terephthalate (rPET) blends is crucial for the effective mechanical recycling of these commercial plastic wastes. This study investigates the reactive extrusion of PP/rPET blends using a dual compatibilizer system comprising maleic anhydride grafted polypropylene (PP-g-MA) and various glycidyl methacrylate (GMA)-based compatibilizers. The effects of backbone structure and reactive group on the morphological, mechanical, and thermal characteristics were systematically studied. This study sheds light on the effective compatibilization mechanisms using characterization methods such as Fourier Transform Infrared Spectroscopy (FTIR) and morphological analyses (SEM). The results indicate that GMA-based compatibilizers play a bridging role between rPET and PP-g-MA, resulting in improved compatibility between the blend components. A combination of 3 phr PP-g-MA and 3 phr ethylene-methyl acrylate glycidyl methacrylate terpolymer (EMA-GMA) significantly improves interfacial adhesion, leading to synergistic enhancements of mechanical performance of the blend, up to 217% and 116% increases in elongation at break and impact strength, respectively, compared to the uncompatibilized sample. Moreover, a significant improvement in onset temperature for degradation is observed for the dual compatibilized sample, with 40 °C and 33 °C increases in onset temperature relative to the uncompatibilized and the single compatibilized samples. These findings underscore the immense potential of tailored multi-component compatibilizer systems for upgrading recycled plastic waste materials.

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The objective of this research was to develop and assess chitosan-grafted copolymer/HZSM5 zeolite Schiff base nanofibers for Cu2+ and Zn2+ adsorption from aqueous media. Nanofibers were prepared via electrospinning and characterized using XRD, FTIR, 1H NMR, FESEM, TGA, BET, and XPS. The study evaluated the effect of unmodified HZSM5 and Schiff base functionalization on adsorption capacities. Incorporating 10.0 wt% zeolite Schiff base as the optimum content into the chitosan-grafted copolymer significantly enhanced adsorption, achieving increases of 98.2 % for Zn2+ and 42.2 % for Cu2+. Specifically, Zn2+ adsorption increased from 27.6 to 54.7 mg/g, and Cu2+ from 67.1 to 95.4 mg/g. Factors such as temperature, pH, adsorption time, and initial cation concentration were analyzed. Kinetic studies revealed a double-exponential model, and isotherm analysis indicated a good fit with the Redlich-Peterson model, showing maximum monolayer capacities of 310.1 mg/g for Cu2+ and 97.8 mg/g for Zn2+ (pH 6.0, 240 min, 45 °C). The adsorption thermodynamics indicated a spontaneous and endothermic adsorption. Reusability tests showed minimal capacity loss (4.91 % for Cu2+ and 5.59 % for Zn2+) after five cycles. The nanofiber displayed greater selectivity for Cu2+ over Zn2+ in multi-ion systems and real electroplating wastewater, highlighting its potential for targeted heavy metal removal.

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Amorphous solid dispersion (ASD) has emerged to be an outstanding strategy among multiple options available for improving solubility and consequently biological activity. Interestingly several binary SD systems continue to exhibit insufficient solubility over time. Therefore, the goal of current research was to design ternary amorphous solid dispersions (ASDs) of hydrophobic model drug curcumin (CUR) to enhance the solubility and dissolution rate in turn, presenting enhanced anti-bacterial, antioxidant and anti-inflammatory activity. For this purpose several ternary solid dispersions (TSDs) consisting of Soluplus®, Syloid® XDP 3150, Syloid® 244 and Poloxamer® 188 in combination with HPMC E5 (binary carrier) were prepared using solvent evaporation method. Both solubility and dissolution testing of prepared solid dispersion were performed to determine the increase in solubility and dissolution. Solid state investigation was carried out utilizing infrared spectroscopy, also known as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM),Differential scanning calorimetry (DSC) and X-ray diffraction (XRD).Optimized formulations were also tested for their biological effectiveness including anti-bacterial, anti-oxidant and anti-inflammatory activity. Amid all Ternary formulations F3 entailing 20 % soluplus® remarkably improved the solubility (186 µg/ml ± 3.95) and consequently dissolution (91 % ± 3.89 %) of curcumin by 3100 and 9 fold respectively. These finding were also supported by FTIR, SEM, XRD and DSC. In-vitro antibacterial investigation of F3 also demonstrated significant improvement in antibacterial activity against both gram positive (Staphylococcus aureus, Bacillus cereus) and gram negative (Pseudomonas aeruginosa, Escherichia coli) bacteria. Among all the tested strains Staphylococcus aureus was found to be most susceptible with a zone of inhibition of 24 mm ± 2.87. Antioxidant activity of F3 was also notably enhanced (93 % ± 5.30) in contrast to CUR (69 % ± 4.79). In vitro anti-inflammatory assessment also exhibited that F3 markedly protected BSA (bovine serum albumin) from denaturation with percent BSA inhibition of 80 % ± 3.16 in comparison to CUR (49 % ± 2.91). Hence, F3 could be an effective solid dispersion system for the delivery of model hydrophobic drug curcumin.

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Proteoglycans (PGs), which have glycosaminoglycan chains attached to their protein cores, are essential for maintaining the morphology and function of healthy body tissues. Extracellular PGs perform various functions, classified into the following four categories: i) the modulation of tissue mechanical properties; ii) the regulation and protection of the extracellular matrix; iii) protein sequestration; and iv) the regulation of cell signaling. The depletion of PGs may significantly impair tissue function, encompassing compromised mechanical characteristics and unregulated inflammatory responses. Since PGs play critical roles in the function of healthy tissues and their synthesis is complex, the development of PG mimetic molecules that recapitulate PG functions for tissue engineering and therapeutic applications has attracted the interest of researchers for more than 20 years. These approaches have ranged from semisynthetic graft copolymers to recombinant PG domains produced by cells that have undergone genetic modifications. This review discusses some essential extracellular PG functions and approaches to mimicking these functions.

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The objective of the present study was to optimize the microwave-assisted synthesis of the acrylamide graft copolymer of Acacia nilotica gum (AM-co-ANG). Furthermore, graft copolymer was used for the formulation of a nanoparticulate system using a novel top to bottom solvent antisolvent technique for the delivery of melatonin. Grafting of ANG was optimized by using 32 factorial design, where concentrations of polymer and monomer (acrylamide) were used as independent variables and swelling index in acidic (0.1 N HCl) and basic (1 N NaOH) pH. Grafted polymers were further used to develop and optimize nanoparticulate system using concentration of the graft copolymer and concentration of drug as independent variables. The size of the nanoformulation and entrapment efficiency were selected as dependent variables. Difference in infrared spectrum and absorbance maxima in the ultraviolet region confirm that grafting has taken place. Porous structure and a higher contact angle confirmed hydrophobic nature of AM-co-ANG as compared with the native polymer. Acrylamide graft copolymers show more swelling in 1 N NaOH as compared with 0.1 N HCl. In vitro toxicity studies in hepatic (HepG2 cell line), brain (SHSY5Y cell line), and skin (HaCaT cell line) cells easily predict that synthesized polymer have no cytotoxicity. The entrapment efficiency ranged from 55.24 ± 1.35% to 73.21 ± 1.83%. A nonlinear correlation was observed between independent and dependent variables, as confirmed by multivariate analysis of variance, surface regression, and the correlation report. The prepared formulations were able to release drug up to 12 h. The regression coefficient easily predicted that most of the formulations followed Baker-Lonsdale drug release kinetics.

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The combination polymers or copolymers have new and combined properties and increase the efficiency of the new polymer. Biopolymers are biodegradable and can play the role of biocompatible and biodegradable in composite polymers. Therefore, poly ortho-toluidine was grafted on chitosan (Cs-g-POT) by chemical and electrochemical polymerization methods. Cs-g-POT was characterized by FTIR, UV-visible, and 1H NMR spectroscopy techniques. The thermal behaviors of the copolymer were investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The images of the surface of the copolymer obtained from imaging SEM confirm the successful attachment of POT on chitosan and indicate that the graft polymerization has been successfully performed with both methods. The percentage and efficiency of engraftment were carefully measured and reported. The electrical conductivity of Cs-g-POT was measured by the four-point method and the conductivity was 9.1 × 10-4 S/cm. The copolymer's antibacterial property was studied on Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa as a common bacterium in skin wounds. These studies were investigated using the disk diffusion and minimum inhibitory concentration (MIC) methods. In all tested concentrations the polymer could inhibit the growth of E. coli and P. aeruginosa significantly. However, it inhibited the growth of S. aureus in concentrations above 1 µg. Bacteria are adsorbed on the surface of the polymer by polar-polar and Van Der Waals interactions, where they undergo cell lysis by dopant and electron transfer, and eventually bacterial cell death. Due to its scaffolding properties, this polymer will have a very good use in tissue and bone repair as well as anti-cancer drugs.

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Dextran (Dx) is a biodegradable and biocompatible polysaccharide, thus promising as a drug delivery carrier for tumor therapy. Herein, we applied mechanical energy to a high molecular weight Dx to control its molecular weight and simultaneously generate mechanoradicals. The solid-state polymerization of methacrylate- or methacrylamide derivatives initiated with Dx mechanoradicals showed polymer conversion of >95%, yielding Dx-based graft copolymers with molecular weights of approximately 30,000 g mol-1. The Dx-based graft copolymers with hydrophobic segments formed nanoparticles with a particle size of 25-35 nm in an aqueous solution. The anti-pancreatic tumor drug 5-fluorouracil (5-FU) was covalently conjugated onto the hydrophobic segments of the amphiphilic Dx, and the nanoparticles were also prepared. The drug release profile from 5-FU-conjugated nanoparticles corresponded well to the Korsmeyer-Peppas model applied to drug release from matrix substrates, and was also immensely predicted by the Logistic and Gompertz curves. The 5-FU-conjugated nanoparticles showed cytotoxicity against the pancreatic adenocarcinoma cell lines (BxPC-3) that were not significantly inferior to the 5-FU positive group. Furthermore, the fluorescein-labeled nanoparticles internalized into BxPC-3 within 6 h and actively migrated into the cytosol. These results suggest that Dx-based graft copolymers with hydrophobic segments might be used to enhance therapeutic activity.

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The aim of this study was to develop a practical orbital shaker-assisted magnetic solid phase extraction (OSA-MSPE) method for the determination of lead by FAAS. A new magnetic poly linoleic acid-polystyrene-polydimethylsiloxane (PSt-PLina-PDMS) hydrophobic graft copolymer was synthesized and characterized by NMR, FT-IR, SEM-EDX, DSC, TGA, BET and used as adsorbent for the extraction of Pb (II). This adsorbent can be used at least 50 times without any decrease of its adsorption properties for the adsorption and elution of analyte ions. Several analytical parameters including pH, adsorbent amount, sample volume, shaking time, etc. were optimized. Multivariate optimization was used for the investigation of different parameters. The linear range at optimum operating condition was 1.7-84 µg L-1. The limit of detection (LOD) and limit of quantification (LOQ) were 0.5 µg L-1, 1.7 µg L-1, respectively. Intraday and interday relative standard deviation (RSD %), enhancement factor (EF) and adsorbent capacity were found as 1.9%, 3.3%, 166.7, 50 mg g-1, respectively. OSA-MSPE method was tested with certified reference materials including LGC-6010 (Hard Drinking Water), NCS ZC73032 Celery and CS-M-3 Control Sample Microelements in Mushroom Powder for the accuracy. Experimental results for lead were confirmed with certified values. Present method was successfully applied to various liquid and solid food samples. The OSA-MSPE method has some important features such as selective, sensitive, low LOD, LOQ and RSD, pre-concentration factor (PF) and high enhancement factor (EF). High tolerance limits against matrix ions were achieved.

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Controlled drug delivery systems offer numerous advantages. This research evaluates Opuntia leaf mucilage grafted with polyacrylamide (OPM-g-PAM) as a promising controlled-release polymer. PAM chains were grafted onto the backbone of OPM using a microwave-assisted method. Optimization of the best grade was based on % grafting efficiency and intrinsic viscosity, followed by extensive physical and analytical characterizations. Analytical characterizations revealed semicrystalline nature of the biomaterial. SEM and AFM observations revealed rough and porous surfaces, indicating effective grafting. Swelling behavior showed maximum sensitivity at pH 7, with reduced swelling at higher sodium chloride concentrations. A comparative study of % drug release of Rosuvastatin over 24 h showed that the optimized grade controlled drug release effectively, achieving 78.5 % release compared to 98.8 % for GF-3. The release data fitted the Korsmeyer-Peppas model, with an "n" value of 0.8334, indicating non-Fickian (anomalous) diffusion. Bacterial biodegradability studies confirmed the high biodegradability of the graft copolymer. In vitro acute toxicity tests showed no toxicity, as confirmed by histopathological studies of heart, liver, and kidney. Overall, the results indicate that OPM-g-PAM is a highly promising material for use in drug delivery systems, demonstrating potential as a novel controlled-release polymer.

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The synergistic effect of drug and gene delivery is expected to significantly improve cancer therapy. However, it is still challenging to design suitable nanocarriers that are able to load simultaneously anticancer drugs and nucleic acids due to their different physico-chemical properties. In the present work, an amphiphilic block copolymer comprising a biocompatible poly(ethylene glycol) (PEG) block and a multi-alkyne-functional biodegradable polycarbonate (PC) block was modified with a number of poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) side chains applying the highly efficient azide-alkyne "click" chemistry reaction. The resulting cationic amphiphilic copolymer with block and graft architecture (MPEG-b-(PC-g-PDMAEMA)) self-associated in aqueous media into nanosized micelles which were loaded with the antioxidant, anti-inflammatory, and anticancer drug quercetin. The drug-loaded nanoparticles were further used to form micelleplexes in aqueous media through electrostatic interactions with DNA. The obtained nanoaggregates-empty and drug-loaded micelles as well as the micelleplexes intended for simultaneous DNA and drug codelivery-were physico-chemically characterized. Additionally, initial in vitro evaluations were performed, indicating the potential application of the novel polymer nanocarriers as drug delivery systems.

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Given the environmental concerns surrounding fluoromaterials, the use of high-cost perfluorinated sulfonic acids (PFSAs) in fuel cells and water electrolysis contradicts the pursuit of clean energy systems. Herein, we present a fluorine-free dumbbell-shaped block-graft copolymer, derived from the cost-effective triblock copolymer, poly(styrene-b-ethylene-co-butylene-b-styrene) (SEBS), for polymer electrolyte membranes (PEMs). This unique polymer shape led to the alignment of the hydrophobic-hydrophilic domains along a preferred orientation, resulting in the construction of interconnected proton channels across the membrane. A bicontinuous network allowed efficient proton transport with reduced tortuosity, leading to an exceptional ionic conductivity (249 mS cm-1 at 80 °C and 90 % relative humidity (RH)), despite a low ion exchange capacity (IEC; 1.41). Furthermore, membrane electrode assembly (MEA) prepared with our membrane exhibited stable performance over a period of 150 h at 80 °C and 30 % RH. This study demonstrates a novel polymer structure design and highlights a promising outlook for hydrocarbon PEMs as alternatives to PFSAs.

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Nanostructures of drug carriers play a crucial role in nanomedicine due to their ability to influence drug delivery. There is yet no clear consensus regarding the optimal size and shape (e.g., aspect ratio) of nanoparticles for minimizing macrophage uptake, given the difficulties in controlling the shape and size of nanoparticles while maintaining identical surface properties. Here, we employed graft copolymer self-assembly to prepare polymer micelles with aspect ratios ranging from 1.0 (spherical) to 10.8 (cylindrical) and closely matched interfacial properties. Notably, our findings emphasize that cylindrical micelles with an aspect ratio of 2.4 are the least susceptible to macrophage uptake compared with both their longer counterparts and spherical micelles. This reduced uptake of the short cylindrical micelles results in a 3.3-fold increase in blood circulation time compared with their spherical counterparts. Controlling the aspect ratio of nanoparticles is crucial for improving drug delivery efficacy through better nanoparticle design.

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Functionalized ultraviolet photocurable bisphenol A-glycerolate dimethacrylates with tailorable size have been synthesized as the core, which have further been grafted using the diisocyanate chain end of polyurethane (PU) as the shell to create a core-shell structure of tunable size for a controlled drug delivery vehicle. The core-shell structure has been elucidated through spectroscopic techniques like 1H NMR, FTIR, and UV-vis and their relative shape and size through TEM and AFM morphology. The greater cross-link density of the core is reflected in the higher glass transition temperature, and the improved thermal stability of the graft copolymer is proven from its thermogravimetric analyses. The flow behavior and enhanced strength of the graft copolymers have been revealed from rheological measurements. The graft copolymer exhibits sustained release of the drug, as compared to pure polyurethane and photopolymer, arising from its core-shell structure and strong interaction between the copolymer and drug, as observed through a significant shifting of absorption peaks in FTIR and UV-vis measurements. Biocompatibility has been tested for the real application of the novel graft copolymer in medical fields, as revealed from MTT assay, cell imaging, and cell adhesion studies. The efficacy of controlled release from a graft copolymer has been verified from the gradual cell killing and ∼70% killing in 3 days vs meager cell killing of ∼25% very quickly in 1 day, followed by the increased cell viability of the system treated with the pure drug. The mechanism of slow and controlled drug release from the core-shell structure has been explored. The fluorescence images support the higher cell-killing efficiency as opposed to a pure drug or a drug embedded in polyurethane. Cells seeded on 3D scaffolds have been developed by embedding a graft copolymer, and fluorescence imaging confirms the successful growth of cells within the scaffold, realizing the potential of the core-shell graft copolymer in the biomedical arena.

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A new graft copolymer composed of polystyrene and polylinoleic acid (PLinas) with the sodium salt of iminodiacetate (Ida) was synthesized and used as an adsorbent. The vortex-assisted dispersive solid-phase micro-extraction (VA-dSPµE) method was used for the extraction and pre-concentration of chromium. Multivariate methodologies, such as factorial design and 3D surface plots, were applied for screening and optimizing effective extraction parameters. The influence of diverse analytical parameters, such as pH, sample volume, and interfering ions, on the extraction of chromium was studied. The calibration standard curve exhibited a linear range from 0.01 to 0.50 µg L-1. The relative standard deviation and limit of detection were found to be 1.65 % and 0.003 µg L-1, respectively. Extraction recoveries were found in the range of 96 to 99 % by using certified reference materials (CRMs). The adsorbent capacity of PLinas-Ida was found to be 112 mg g-1. The VA-dSPµE method demonstrated its effectiveness in the pre-concentration and determination of chromium within samples of foodstuffs by graphite furnace-atomic absorption spectrometry (GF-AAS).

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The binary metal oxide mesoporous interfacial layers (bi-MO meso IF layer) templated by a graft copolymer are synthesized between a fluorine-doped tin oxide (FTO) substrate and nanocrystalline TiO2 (nc-TiO2). Amphiphilic graft copolymers, Poly(epichlorohydrin)-graft-poly(styrene), PECH-g-PS, were used as a structure-directing agent, and the fabricated bi-MO meso IF layer exhibits good interconnectivity and high porosity. Even if the amount of ZnO in bi-MO meso IF layer increased, it was confirmed that the morphology and porosity of the bi-MO meso IF layer were well-maintained. In addtion, the bi-MO meso IF layer coated onto FTO substrates shows higher transmittance compared with a pristine FTO substrate and dense-TiO2/FTO, due to the reduced surface roughness of FTO. The overall conversion efficiency (η) of solid-state photovoltaic cells, dye-sensitized solar cells (DSSCs) fabricated with nc-TiO2 layer/bi-MO meso IF layer TZ1 used as a photoanode, reaches 5.0% at 100 mW cm-2, which is higher than that of DSSCs with an nc-TiO2 layer/dense-TiO2 layer (4.2%), resulting from enhanced light harvesting, good interconnectivity, and reduced interfacial resistance. The cell efficiency of the device did not change after 15 days, indicating that the bi-MO meso IF layer with solid-state electrolyte has improved electrode/electrolyte interface and electrochemical stability. Additionally, commercial scattering layer/nc-TiO2 layer/bi-MO meso IF layer TZ1 photoanode-fabricated solid-state photovoltaic cells (DSSCs) achieved an overall conversion efficiency (η) of 6.4% at 100 mW cm-2.

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Fluorinated proton-exchange membranes (PEMs) based on graft copolymers of dehydrofluorinated polyvinylidene fluoride (D-PVDF), 3-sulfopropyl acrylate (SPA), and 1H, 1H, 2H-perfluoro-1-hexene (PFH) were prepared via free radical copolymerization and characterized for fuel cell application. The membrane morphology and physical properties were studied via small-(SAXS) and wide-angle X-ray scattering (WAXS), SEM, and DSC. It was found that the crystallinity degree is 17% for PEM-RCF (co-polymer with SPA) and 16% for PEM-RCF-2 (copolymer with SPA and PFH). The designed membranes possess crystallite grains of 5-6 nm in diameter. SEM images reveal a structure with open pores on the surface of diameters from 20 to 140 nm. Their transport and electrochemical characterization shows that the lowest membrane area resistance (0.9 Ωcm2) is comparable to perfluorosulfonic acid PEMs (such as Nafion®) and polyvinylidene fluoride (PVDF) based CJMC cation-exchange membranes (ChemJoy Polymer Materials, China). Key transport and physicochemical properties of new and commercial membranes were compared. The PEM-RCF permeability to NaCl diffusion is rather high, which is due to a relatively low concentration of fixed sulfonate groups. Voltammetry confers that the electrochemical behavior of new PEM correlates to that of commercial cation-exchange membranes, while the ionic conductivity reveals an impact of the extended pores, as in track-etched membranes.

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Utilizing macroalgal waste biomass for pollution management is a highly efficient method for addressing the environmental difficulties associated with its disposal. To accomplish this, we have attempted to synthesize a graft copolymer by combining ulvan, a sulfated polysaccharide isolated from seaweed, with acrylates. A one-pot synthesis method using UV-initiated graft polymerization with V-50 as the photoinitiator resulted in the production of a distinctive, high-performance, and eco-friendly flocculant, Ulvan-g-Poly (acrylamide-co-acrylic acid) referred as P(U_AAm_AAc). The synthesis was optimized using the CCD-RSM approach, employing molecular weight and inherent viscosity as indicators to optimize the parameters. The structural and physio-chemical properties of the synthesized P(U_AAm_AAc) were characterized utilizing XRD, ATR-FTIR, ζ-potential, and H1 NMR spectroscopy. The flocculation performance of P(U_AAm_AAc) was further examined for the removal of oils from samples with high neem oil in urea solution and low crude oil in seawater. By employing a coagulant-flocculant combination of poly-aluminium chloride (PAC) and P(U_AAm_AAc), it was noted that more than 94% of oil was effectively eliminated in both samples. Optimization of the dosage of P(U_AAm_AAc) resulted in enhanced turbidity reduction and improved dewatering efficiency of the filter cake generated following flocculation. An evaluation of performance was conducted using the commercial flocculant APAM, where synthesized P(U_AAm_AAc) demonstrated similar results. In conclusion, the findings of this research highlight the potential of P(U_AAm_AAc) as a sustainable alternative to commercial flocculants with multifaceted solution to coastal waste management, paving the way for a cleaner and healthier marine ecosystem to mitigate oil emulsion pollution.

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Chitosan, a cost-effective and eco-friendly natural polymeric material, possesses excellent film-forming properties. However, it has low solubility and biological activity, which hinders its widespread applications. To overcome these limitations, researchers have developed phenolic acid-chitosan derivatives that greatly enhance the mechanical, antibacterial and antioxidant properties of chitosan, expanding its potential application, particularly in food preservation. This review aims to provide an in-depth understanding of the structure and biological activity of chitosan and phenolic acid, as well as various synthetic techniques employed in their modification. Phenolic acid-chitosan derivatives exhibit improved physicochemical properties, such as enhanced water solubility, thermal stability, rheological properties, and crystallinity, through grafting techniques. Moreover, these derivatives demonstrate significantly enhanced antibacterial and antioxidant activities. Through graft modification, phenolic acid-chitosan derivatives offer promising applications in food preservation for diverse food products, including fruits, vegetables, meat, and aquatic products. Their ability to improve the preservation and quality of these food items makes them an appealing option for the food industry. This review intends to provide a deeper understanding of phenolic acid-chitosan derivatives by delving into their synthetic technology, characterization, and application in the realm of food preservation.

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Chitosan-grafted-poly(acrylic acid) (CS-g-PAA) and chitosan-grafted- poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (CS-g-P(AA-co-AMPS)) hydrogels were synthesized and then employed as adsorbents for the effective removal of Cu2+ and other heavy metal ions. The effect of hydrogel's composition on the Cu2+ adsorption was explored. The CS-g-PAA hydrogel demonstrated a superior adsorption capacity compared to pristine CS, PAA hydrogel, and CS-g-P(AA-co-AMPS) hydrogels. The adsorption followed the Langmuir isotherm model, and the pseudo-second order kinetic model. Additionally, the CS-g-PAA hydrogel exhibited relatively high adsorption performances toward Cr3+, Co2+, Ni2+, Pb2+, and Zn2+. Metal ions adsorbed within CS-g-PAA hydrogels underwent reduction to their corresponding metallic states and were reutilized as catalysts for the reduction of 4-nitrophenol. The comparative catalytic performances of the metal species in the hydrogel were in the order of Cu > Ni > Co > Zn. The reduction efficiency of Cu-CS-g-PAA increased with increased catalyst dosage, NaBH4 concentration, and temperature. A very low activation energy of 3.7 kJ/mol was observed. The catalyst maintained high catalytic performance even when subjected to real water samples and proved its reusability for up to three cycles. Moreover, the catalyst could effectively reduce 2-nitrophenol and methyl orange.

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Present study focuses on the use of a biodegradable and cost-effective cation exchanger for removal of Cr (VI) metal ions from water sources. Semi-IPN was prepared through grafting of acrylamide onto agar-polyvinyl alcohol backbone in presence of boric acid and ammonium per sulphate as crosslinker-initiator system. Graft copolymer was converted to cation exchanger through phosphorylation. Characterization was done using methods such as FTIR, SEM-EDX and XRD. Semi-IPN exhibited higher thermal resistance. The findings revealed that the optimum conditions for Cr (VI) removal are pH = 4.0; contact time (min) = 360; adsorbent dose (mg) = 125 and metal ion concentration(mg/L) =2. The adsorption kinetics of Cr (VI) ions are best fit by the pseudo second order kinetic with 0.99 R2 and Kf (rate constant) was found to be 0.97 thereby supporting the Freundlich isotherm. The adsorption isotherm models used in this study were consistent with the Freundlich model, but the pseudo second order model was the most accurate description of the adsorption kinetics. The present investigation showed an excellent potential with 85 % adsorption capacity for the removal of Cr (VI). Moreover, reusability studies showed that the cation exchanger can be used effectively up to four cycles.

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