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The present study describes the facile synthesis of graphene oxide (GO) and GO/carboxymethyl tamarind kernel gum (CMTKG)-based hydrogel composite. The synthesized GO/CMTKG/PAM hydrogel composite was applied as an adsorbent for the selective sequestration of toxic crystal violet (CV) and methylene blue (MB) from an aqueous medium. The impact of various controlling parameters such as contact time, pH, concentration, adsorbent dosage. and temperature was studied. The experimental data obtained from the isotherm and kinetics modeling showed a good correlation with the Langmuir isotherm and pseudo-second-order kinetics model, respectively. The optimized concentration of dye was 40 mg [L.sup.-1] for CV and 20 mg [L.sup.-1] for MB, and the adsorption capacity ([q.sub.max]) was calculated to be 111 mg [g.sup.-1] for CV dye and 25 mg [g.sup.-1] for MB dye. The synthesized adsorbent exhibits excellent recyclability for dye uptake after six consecutive cycles. Furthermore, the simultaneous adsorption of CV and MB from the binary system was carried out to ascertain the utility of the adsorbent in a wide range of adsorption systems. The adsorbent was also found to act as a proficient adsorbent in various water samples. These results demonstrated that synthesized hydrogel can be successfully applied as an adsorbent for the sequestration of dye effluents in real-time applications. Highlights * Hydrogel composite was successfully synthesized via a free radical mechanism. * It is an efficient adsorbent for removing cationic dyes from aqueous solutions. * It shows selectivity towards cationic dyes and works in a binary mixture of cationic dyes. * It shows good removal efficacy in different water samples, including real wastewater samples. * It also shows proficient removal efficacy after six consecutive regeneration cycles. KEYWORDS adsorption, cationic dyes, CMTKG, GO, hydrogel composite, water treatment, 1 | INTRODUCTION Water makes up more than 71% of our planet, but less than 3% is fit for consumption. As a result, many regions of the world face a [...]

In this study, crosslinked films of polyvinyl alcohol (PVA) were prepared using two dicarboxylic acids: saturated succinic acid (SA) and unsaturated maleic acid (MAL) as crosslinkers. The crosslinking capabilities of these acids were compared through physical, chemical, mechanical, morphological, thermal analysis, and swelling measurements to investigate their impact on the physicochemical properties of the resulting films. Attenuated total reflectance fourier transform infrared spectroscopy (FTIR) confirmed the occurrence of an esterification reaction between PVA and the dicarboxylic acids. Based on the degree of crosslinking and thermal properties, it was noted that the crosslinking achieved with maleic acid is more effective for PVA compared with succinic acid. The crosslinking degree of PVA-MAL was determined to be 6.47 times higher than that of the PVA-SA film. In terms of thermal stability, the decomposition temperature for crosslinked PVA-MAL was measured at 365.57[degrees]C, whereas PVA-SA exhibited a slightly lower decomposition temperature of 362.58[degrees]C. The findings indicate that the PVA-MAL film displays lower crystallinity and a higher contact angle (80.60[degrees]) in contrast to PVA-SA (76.0[degrees]) and PVA (30.4[degrees]). Atomic force microscopy analysis indicated that the PVA-SA film exhibited more surface roughness compared with the smoother PVA-MAL film. Also, crosslinked films displayed enhanced elasticity and resilience in comparison with neat PVA, which may be due to the difference in crosslinking density, disruption in intermolecular hydrogen bonding due to crosslinking, and incorporation of flexible crosslinkers. Highlights * PVA was crosslinked using SA and MAL. * Unsaturated MAL exhibited superior crosslinking density over saturated SA. * PVA-SA film exhibited a porous surface compared to PVA-MAL film. * PVA crosslinked with unsaturated MAL showed higher thermal stability than SA. * Both the films showed enhanced elasticity and resilience compared with neat PVA. KEYWORDS carboxylic acids crosslinked PVA, physicochemical properties of polymer, PVA, 1 | INTRODUCTION Polyvinyl alcohol (PVA) stands out as a highly promising semicrystalline polymer with a range of notable properties, including biocompatibility, water solubility, ready availability, low cost, non-toxicity, and [...]

Polyvinyl alcohol (PVA) is a nontoxic, biodegradable, and biocompatible polymer and has been used extensively in various fields. Indeed, important features of PVA such as its film-forming ability, high tensile strength and flexibility, high viscosity, solvent tolerance ability, thermostable nature have made it vital and drawn the attention of scientific community. However, being a watersoluble polymer, some chemical modifications are required to alter this property of PVA. Cross-linking is the most attractive and widely used method to change the properties of PVA to make it more valuable material. Different carboxylic acids have already been used for PVA cross-linking in various applications such as pervaporation, reverse osmosis (RO), wound dressing, drug delivery, and fuel cells. However, a comprehensive study on structure-property correlation of carboxylic acids as PVA cross-linker is not available. In this review, different available studies on carboxylic acid cross-linked PVA are summarized and are used to develop structure-property correlations of carboxylic acids as cross-linker on the properties of cross-linked PVA. Advantages and limitations of different carboxylic acids as PVA cross-linker are also summarized for various fields such as tissue engineering, wound dressing, drug delivery, fuel cell/ solid polymer electrolyte, pervaporation, desalination and RO solid polymer electrolytes, and food packaging. KEYWORDS carboxylic acids, cross-linked PVA, cross-linking, films, membranes, water- soluble polymers, 1 | INTRODUCTION Polyvinyl alcohol (PVA) is a synthetic, linear, semicrystalline polymer that is composed of carbon chain as backbone and hydroxyl group as a functional group. It is obtained [...]

Polyvinyl alcohol (PVA) was crosslinked with a homologous series of four different dicarboxylic acids, HOOC(CH2) n‐2COOH (n = 2 to 5) viz. oxalic acid (OA; C2), malonic acid (MA; C3), succinic acid (SA; C4) and glutaric acid (GA; C5) containing odd and even number of carbon atoms. The characterization and assessment of synthesized crosslinked films were done using ATR‐FTIR, XRD, SEM, AFM, DSC, rheology, percent swelling and sessile drop contact angle. The odd‐even effect of dicarboxylic acids was observed to significantly influence the physicochemical properties of PVA when employed as a crosslinker. PVA films crosslinked using dicarboxylic acids containing an even number of carbon atoms, displayed translucency, roughness, and an irregular matrix. In contrast, films incorporating an odd number of carbon atoms were transparent, homogenous, and densely packed. Furthermore, films containing even acids exhibited relatively lower crystallinity, lower melting temperature (Tm) and displayed an unexpected irregular trend in swelling as crosslinker concentration increased compared to films containing dicarboxylic acids with an odd number of carbon atoms which exhibits a consistent swelling with increasing crosslinker concentration. These results are attributed to the difference in the solubility and crystal structures of the odd‐even series of dicarboxylic acids. [ABSTRACT FROM AUTHOR]

In this current study, hydrogels based on acacia gum (AG), polyacrylamide (PAM), and carboxymethyl tamarind kernel gum (CMTKG) were successfully developed and ciprofloxacin (drug) incorporated into it. To optimize the hydrogel, the concentrations of crosslinker and initiator were varied, and their effects on the swelling were examined. The hydrogel was subjected to characterization techniques such as Powder X‐ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), Attenuated Total Reflection‐Fourier Transform Infrared spectroscopy (ATR‐FTIR), and Thermogravimetric analysis (TGA). The hydrogel swelling and in vitro drug release were assessed in pH 1.2 and 7.4 buffer solutions. The findings revealed that an alkaline pH yielded superior results for the swelling and in vitro drug release experiments compared to an acidic pH. The drug release kinetic of the ciprofloxacin‐loaded AG/PAM/CMTKG hydrogel followed the Korsmeyer–Peppas model, demonstrating non‐fickian diffusion at pH 7.4 and fickian mechanism at pH 1.2. The pH‐dependent behavior of ciprofloxacin‐loaded AG/PAM/CMTKG hydrogel displayed its potential implications for site‐specific ciprofloxacin release. [ABSTRACT FROM AUTHOR]

Gelatin-based hydrogels, despite their excellent biocompatibility, face limitations in their utility for targeted drug release due to low mechanical strength. Thus, this research is directed towards the fabrication of pH-responsive hydrogels based on gelatin, polyacrylamide (PAM) and carboxymethyl tamarind kernel gum (CMTKG), followed by their loading with ampicillin sodium drug. The hydrogel has been optimized by varying crosslinker, and initiator amounts to observe their effect on swelling. The swelling is increased with an increase ininitiator, reaching a maximum of 1371% at pH 7.4 and 1218% at pH 1.2. The hydrogels are analyzed through Scanning Electron Microscopy (SEM), Powder X-ray Diffraction (PXRD), and Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR) techniques. Various parameters such as drug loading, porosity, and gel fraction are evaluated. The in vitro drug release is evaluated in both pH 1.2 and 7.4 buffer, with higher drug release (63.3%) observed under alkaline pH. The kinetic modeling data validates the Korsmeyer-Peppas model (R² = 0.9871) to be the suitable model for the explanation of the drug release mechanism, suggesting the Fickian diffusion (n<0.5, pH 1.2) and non-Fickian diffusion (n>0.5, pH 7.4). Therefore, the Gelatin/PAM/CMTKG hydrogel shows potential for targeted release of ampicillin sodium in response to varying pH. [ABSTRACT FROM AUTHOR]

This research delves into the development of a hydrogel based on sodium alginate (Na‐Alg), CMTKG and PSA for the controlled release of Metformin Hydrochloride (Metformin HCl), a commonly used drug for the treatment of type 2 diabetes. The hydrogel was synthesized via a free radical mechanism using N, N′‐methylene‐bis(acrylamide) (MBA) as a crosslinker and potassium persulphate (KPS) as an initiator. The hydrogels were analyzed using techniques such as ATR‐FTIR, and SEM. The research also investigated swelling behaviour, drug loading, drug encapsulation efficiency, and release kinetics of Metformin HCl. The finding revealed that the hydrogel exhibited pH‐responsive metformin HCl release, with higher drug release perceived at pH 7.4 compared to pH 1.2. Mathematical models were employed to study the drug release mechanism, indicating diffusion as a mechanism liable for the drug release from the hydrogel. Moreover, the synthesized metformin HCl‐loaded Na‐Alg/PSA/CMTKG hydrogel shows excellent anti‐diabetic activity on α‐amylase and α‐glucosidase enzyme. Henceforth, the formulated hydrogel reveals potential for facilitating the targeted release of Metformin HCl, offering opportunities for improving patient amenability and lessening side effects related to frequent dosing. [ABSTRACT FROM AUTHOR]

The incorporation of biopolymer nanoparticles with potential antioxidant properties into biomaterials for human health care is significant. The current study focuses on nanoparticles carboxymethyl tamarind kernel gum (CMTKG) composite materials because of their potential applications. The co-precipitation method was used to create carboxymethyl tamarind kernel gum nanoparticles (CMTKG-NPs). This technique was used for the first time to create carboxymethyl tamarind kernel gum nanoparticles. The strength of nanoparticle conformation is reported to be influenced by co-precipitation and stirring time. Nanoparticles were characterised using high-resolution transmission electron microscopy (HR-TEM), field emission scanning electron microscopy (FE-SEM), fourier transform infrared (FTIR), x-ray diffraction analysis (XRD), and thermogravimetric analysis (TGA). Suspense particle sizes have been determined to be in the 40-60 nm range. It was concluded that similar nanoparticles could be used in antioxidant activities. [ABSTRACT FROM AUTHOR]

Biopolymers are fourth generation packaging materials. Due to the shortcomings of the petrochemical‐based polymers and their threat to the environment, biopolymers are seen as the sustainable substitute for traditional synthetic polymers and have attracted the researchers towards the development of biopolymer‐based packaging materials. However, biopolymers suffer from flaws like inferior mechanical strength and thermal stability, which poses its inability to use at industrial scale. The recent studies thus highlighted the different modification methods such as reactive or nonreactive compatibilisation to conquer such issues. The present article recapitulates the various biopolymers developed in the recent past, modification methods for their processing and their packaging applications. [ABSTRACT FROM AUTHOR]

The formation of novel Polycaprolactone (PCL) copolymers, blends, and composites is used to broaden the versatility and applicability of the polymer. In the last decade, PCL copolymers, blends, and composites have been investigated well to tune their characteristics and properties. The review highlights thermal, mechanical, rheological, structural, electrical, shape memory, and degradation properties. Their biodegradability and modified properties make it an environment-friendly material to be used in various fields including biomedical, packaging, self-healing, coatings, oil-water separation, photo-thermal absorption and plant grafting. The commercial products based on polycaprolactone are listed in this review. Further, future recommendations for new research directions are provided. [ABSTRACT FROM AUTHOR]