Methacrylic Acid Content Research Articles

Surface characterization of drying acrylic latex dispersions with variable methacrylic acid content using surface dilatational rheology

HypothesisDrying of latex dispersions often results in particle gradients at the latex-air interface. We expect that, by increasing the carboxylic acid content of latex particles, inter-particle interactions at the interface change. With dilatational rheology one could detect particle-particle interactions in an early stage of the drying process and elucidate the nature of these interactions. ExperimentsAcrylic latex dispersions were prepared with different amounts of methacrylic acid (MAA), ranging from 2 to 10 wt% on dry mass. Dilatational rheology studies during drying at different relative humidities RH were performed using profile analysis tensiometry. Visco-elastic properties of latex surfaces were used to identify inter-particle interactions at the surfaces depending on the drying rate and particle composition. FindingsDrying at 85% RH did not show significant changes of the mechanical properties of the latex surfaces. Drying at 65 and 53% RH resulted in a change of the mechanical properties, ultimately showing non-linear visco-elastic behavior. This indicates that capillary and/or Van der Waals forces were operating between particles at the surface. With increasing MAA content the viscous contribution decreased, possibly due to the formation of more gel-like structures at the particle surface due to higher solubility of polymer segments near to the surface.

Synthesis of bio-based methacrylic acid from biomass-derived itaconic acid over barium hexa-aluminate catalyst by selective decarboxylation reaction

An environmentally-benign, efficient and inexpensive high-surface-area barium hexa-aluminate (BaAl12O19, BHA) was developed as a catalyst for the decarboxylation of the biomass-derived itaconic acid (IA) to bio-based methacrylic acid (MAA). A maximal 50% final yield of MAA with a high product selectivity was obtained under relatively mild synthesis reaction conditions (250 °C; 20 bar N2). The reported selective MAA production was elevated, operating process characteristics were significantly less harsh, and no depleting critical raw materials were utilized when paralleled to the procedures with alkaline mineral bases, noble metal-containing heterogeneous catalysis systems and unrenewable feed resources (e.g. isobutene), applied previously. It was found that the doping of palladium on BHA support (Pd@BHA) did not improve MAA productivity. The effect of the time (25–300 min), temperature (175–275 °C), pressure (10–40 bar), reacting substrate concentration (0.10–0.19 mol L–1), metallic oxide mass (0.5–3.0 g) and type on IA conversion, MAA content MAA content and rates was determined, examining also recyclability. BHA catalyst was characterized with various structural techniques, such as energy-dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD), CO2 temperature-programmed desorption (TPD), scanning electron microscopy (SEM) and N2 physisorption.

Developing Ag-tercopolymer microgels for the catalytic reduction of p-nitrophenol and EosinY throughout the entire pH range

In this study ter-copolymer microgel networks of thermo sensitive N-isopropyl acrylamide (NIPAm), pH sensitive methacrylic acid (MAA) and 2-hydroxyethyl methacrylate (HEMA) monomers were prepared with different MAA content. Ag nanoparticles were stabilized in ter-copolymer microgel networks at pH 3 and 7. The size of microgel particles was studied at different environmental temperature and pH using the Zetasizer Nano and scanning electron microscopy. The thermal stability and metal content in hybrid microgels were confirmed by thermal gravimetric analysis. The hybrid microgels were tested for their catalytic behavior towards the reduction of toxic pollutants p-nitrophenol (pNP) and Eosin Y (EY) with sodium borohydride at the entire pH range (2 to 9, SD ± 0.2). The hybrid microgels prepared at pH 7 showed enhanced catalytic performance because of the high content of Ag nanoparticles, while after the preparation, the catalytic property of the catalysts was found decrease with the increase in environmental pH. It was due to the collapse of the microgel network, which further brings the Ag nanoparticles closer in proximity to each other and enhanced the collision rate of reactants with the surface of catalysts which increased the conversion rate. The composition having high content of MAA showed maximum kapp values i.e. 0.45562 and 0.62537 min−1 towards pNP and EY respectively. The catalysts were recycled and reused for multiple cycles with a negligible decrease in their catalytic rate.

Nitroxide-mediated polymerization of methacrylates in the presence of 4-vinyl pyridine as controlling comonomer

The controlled polymerization of methacrylic monomers by nitroxide-mediated polymerization (NMP) still represents a challenge in polymer science. This issue can be circumvented by the addition of a small amount of a comonomer known to exhibit a controlled character in NMP, the most representative example being styrene. The purpose of this work is to explore the use of 4-vinyl pyridine (4VP) as controlling comonomer, while conferring at the same time some functionality to the polymer chains. The NMP of methyl methacrylate (MMA), poly(ethylene glycol) methyl ether methacrylate (PEOMA950, Mn = 950 g mol−1) and methacrylic acid (MAA) using a small amount of 4VP under mild experimental conditions (<90 °C, atmospheric pressure), was investigated in this work. The copolymerization of MMA or PEOMA950 with 10 mol% 4VP, mediated by the use of the BlocBuilder® alkoxyamine and a small amount of free nitroxide SG1, exhibited all the features of a controlled system in agreement with the favored incorporation of 4VP at the chain ends, leading to an efficient deactivation of the propagating radicals by the nitroxide SG1. In contrast, the polymerization of MAA was uncontrolled in the same conditions likely due to acid/base interaction between MAA and 4VP, affecting the reactivity of the functional comonomer. Consistently, the copolymerization of MAA with MMA also led to a progressive loss of control as the MAA content in the feed was increased. Among all the polymers synthesized, the P(MMA72-co-4VP10)-SG1 macroalkoyamine was then successfully used to reinitiate the copolymerization of n-butyl methacrylate (BMA) and 4VP both in solution and via dispersion polymerization in a mixture of ethanol and water. Finally, raspberry-like polymer/silica composite particles were prepared through nitroxide-mediated dispersion polymerization performed in the presence of silica nanoparticles, taking benefit of the strong acid-base interaction between 4VP and silica.

Some Properties of Chemical Cross-Linking Biohydrogel from Starch and Chitosan.

Chemical cross-linking was developed to prepare starch and chitosan-based hydrogels. First, the precursor of starch was synthesized through the reaction of carboxymethylation with sodium monochloroacetate, and then chitosan was grafted by using methacrylic acid as cross-linker. In this research, sago and cassava starches were used and mixed with chitosan, and the effect of methacrylic acid concentration was investigated to determine the grafting parameters and hydrogel characteristics. Compared to native starch and carboxymethylated starch, hydrogels from both starches have high ability to swell and high capacity to absorb water and oil. The highest grafting yield, grafting efficiency, and monomer conversion were achieved by experiment using 0.550 g of methacrylic acid per g of CMS-chitosan mixture. These hydrogels have a good potency as biodegradable absorbents for pharmaceutical and industrial application.

Hydroplasticization of latex films with varying methacrylic acid content

The hydroplasticization of coatings of acrylic copolymers with different amounts of methacrylic acid (MAA) was investigated to clarify the role of carboxylic acid functionalities on the change in polymer mobility due to water uptake. The coating Tg as a function of water uptake was studied using dynamic mechanical analysis. The Tg’s decreased with increasing water content, confirming the plasticizing effect of water on the coatings. At relative humidities RH between 0 and 60% the coating Tg shows a sharper decrease than at higher RH, an effect that increases with increasing MAA content. This behavior is attributed to the presence of dimers of carboxylic acid in the coatings, which is also observed with FTIR-ATR analyses. Due to water uptake, the dimers are disrupted and form “open” dimers where carboxylic acid groups remain in close proximity and are connected through water molecules. With 1H NMR relaxometry, two T2 relaxation times are found, representing two hydrogen pools with different mobilities. Both mobilities increase with increasing water content, indicating the presence of polymer domains with different hardness. Correlating the T2 relaxation times with the coating Tg’s shows that at higher MAA content the proton mobility as a function of Tg of the soft domains increases with increasing MAA content. Since the polymer proton mobility, and hence the polymer mobility, is expected to scale with the polymer Tg, it is hypothesized that harder domains are present in the coatings, which are not visible in the Ostroff-Waugh decays due to the fast relaxation behavior of these protons.

High performance biocompatible cellulose‐based microcapsules encapsulating gallic acid prepared by inverse microsuspension polymerization

AbstractIn this study, the preparation of biocompatible cellulose‐based microcapsules encapsulating gallic acid (GA), an important antioxidant of Bambara groundnut extracts, by water‐in‐oil inverse microsuspension polymerization was studied. GA and carboxymethyl cellulose (CMC) were selected as core and shell materials, respectively. For high encapsulation efficiency, CMC was firstly modified (modified‐CMC (m‐CMC)) with 3‐(trimethoxysilyl)propyl methacrylate (MPS) as a silane coupling agent. It was subsequently polymerized with methacrylic acid (MAA) monomer through a radical route, forming a PMAA grafted m‐CMC (m‐CMC‐g‐PMAA) biocompatible polymer shell. Using CMC:MPS in a ratio of 75:25 (w/w %), highly water‐soluble m‐CMC containing a C=C bond for further radical polymerization was obtained. After inverse microsuspension polymerization at various ratios of m‐CMC:MAA, highly stable spherical m‐CMC‐g‐PMAA microcapsules encapsulating GA were formed in all ratios. It was observed that the encapsulation efficiency increased with increase in MAA content. m‐CMC:MAA in a ratio of 33:67 (w/w%) presented the highest encapsulation efficiency which may due to the increase of hydrophilicity of the aqueous phase. It also presented rapid release and non‐cytotoxic characteristics, suited for use in cosmetic products. © 2018 Society of Chemical Industry

Characterization and properties of biodegradable thermoplastic grafted starch films by different contents of methacrylic acid

Due to poor mechanical and thermal properties of native starch (NS) film; in the present work; NS was modified by graft copolymerization. Thermoplastic starch (TPS) grafted by methacrylic acid (MAA) with different percentage of grafting, i.e., 0%, 18.3%, 36.3%, 52.1% and 89.7% were prepared and tested. The result demonstrated that the intensity of IR peak of acrylic group increased with the increasing percentage of grafting. The higher graft copolymerization with MAA also significantly reduced degree of crystallinity. The strain at maximum load of TPS film grafted by MAA increased with the increasing percentage of grafting. However, water uptake of TPS film grafted by MAA reduced with high percentage of grafting (52.1% and 89.7%). In addition, different TPS films grafted by MAA were also examined for morphology, water vapor permeability, thermal property and biodegradable property by soil buried test.

The Role of the Chelating Agent on the Structure and Anticorrosion Performances of an Organosilane—Zirconium Sol-Gel Coatings

This work investigates the role of the structure of a zirconium complex (ZC) on the condensation and anticorrosion properties of an organosilane sol-gel coating. The structure and reactivity of the ZC were modified by varying the content of methacrylic acid employed as a chelating agent. The structures of the developed materials were characterised by Dynamic Light Scattering, Fourier Transform Infrared Spectroscopy, Differential Scanning Calorimetry and Scanning Electron Microscopy. The passive anticorrosion properties were evaluated by Electrochemical Impedance Spectroscopy of the sol-gel coatings deposited on AA2024-T3 substrates. It was highlighted, that a competition in the condensation process of the silicate (Si-O-Si) and silicon-ZC oxides (Si-O-Zr) species can be tailored by the structure of the ZC, with the least chelated ZC exhibiting the highest content of Si-O-Zr bonds. At the same time, it was also found that the coatings containing the highest content of Si-O-Zr groups exhibited the best anticorrosion barrier performances amongst all sol-gel coatings investigated here, therefore presenting the highest condensation degree. This suggested that Si-O-Zr bonds were the essential chemical species responsible for the formation of condensed coatings. A direct correlation between the structure of the coatings and their anticorrosion performances is proposed.

Physical Properties of Heat Cure Denture Base Resin after Incorporation of Methacrylic Acid.

Introduction:Heat cure acrylic resins are the most commonly used denture base materials. The important limitation is they may act as reservoir of microorganisms. The adherence of microorganisms can be reduced by chemical modification of the surface charge of denture base resin. Incorporation of methacrylic acid (MA) in the denture base resin gives a negative surface charge. A denture base having a negative surface charge may hinder the initial adhesion of microorganisms through repulsive electrostatic forces.Aims and Objectives:The present in vitro study was performed to determine the effect of addition of antimicrobial agent MA on the flexural strength and surface roughness of heat cure denture base resin.Materials and Methods:A total of 90 heat cure acrylic specimens were prepared. Of 90 specimens, 30 were prepared as Group I control group without addition of MA. Groups II and III specimens were prepared by adding 10% and 20% MA, respectively. Using universal testing machine and surface roughness tester, flexural strength and surface roughness of specimens measured.Results:In the present study, decrease in the flexural strength was observed when the concentration of the MA increased in the denture base resin. A slight increase in the surface roughness was observed as the concentration of MA increased.

Recovery of methacrylic acid from dilute aqueous solutions by ionic liquids though hydrogen bonding interaction

Abstract The recovery of carboxylic acids from dilute aqueous solution is necessary but difficult in chemical industry. Methacrylic acid (MAA) is an important chemical widely used in polymer industry. In this work, the recovery of carboxylic acid from diluted aqueous solution by liquid-liquid extraction using ionic liquids (ILs) as extractants was studied. MAA was employed as model carboxylic acid. The partition coefficients of MAA in biphasic system and the extraction efficiencies of MAA were determined for imidazolium-based ILs and quaternary ammonium salt ILs with different structure of cation and anion. The extraction conditions such as extraction time, extraction temperature, mass ratio of ILs to MAA aqueous solution, initial concentrations of MAA, and water content were evaluated. An internal mechanism of the MAA extract by ILs was revealed by combining solvatochromic study, FT-IR and quantum chemical calculations. The results show that the strong hydrogen bond basicity (β) of ILs results in the high partition coefficient of MAA, which provides guidance to molecular design of ILs for the high efficient extractive separation of MAA from diluted aqueous solution. Based on this, IL with strong hydrogen bond basicity ([N8881]Cl) was used to extract MAA from dilute aqueous solution. Compared with hexane which is conventional solvent used in MAA extractive separation, [N8881]Cl can get 49 times higher of partition coefficient value and the extraction efficiency reach 94.57% for the single-stage extraction.

Anisotropic pH-Responsive Hydrogels Containing Soft or Hard Rod-Like Particles Assembled Using Low Shear

A simple and versatile low-shear approach for assembling hydrogels containing aligned rod-like particles (RLPs) that are birefringent and exhibit pH-triggered anisotropic swelling is developed. Anisotropic composite hydrogels are prepared by applying low shear (0.1 s–1) to mixtures of pH-responsive nanogels (NGs) and RLPs. The NGs, which contained high methacrylic acid contents, acted as both shear transfer vehicles and macro-cross-linkers for anisotropic gel formation. Three model RLP systems are investigated: (i) soft triblock copolymer worms, (ii) stiff self-assembled β-sheet peptide fibers, and (iii) ultrahigh modulus nanocrystalline cellulose fibers. RLP alignment was confirmed using polarized light imaging, atomic force microscopy, and small-angle X-ray scattering as well as modulus and anisotropic swelling experiments. Unexpectedly, the composite gel containing the soft copolymer worms showed the most pronounced anisotropy swelling. The copolymer worms enabled higher RLP loadings than was possible ...

Thermal studies on proton conductive copolymer thin films based on perfluoroacrylates synthesized by initiated Chemical Vapor Deposition

The thermal properties of ion-conductive materials are crucial for their use in temperature-sensitive applications such as polymer electrolyte fuel cells. In this study, 1H,1H,2H,2H,-perfluorodecyl acrylate and methacrylic acid (MAA) copolymers are synthesized by initiated Chemical Vapor Deposition. This method is a solvent-free thin film deposition technique, which allows for the preparation of polymers in distinct stoichiometric compositions. The chemical stability of the copolymers was investigated upon elevated temperatures along with other thermal properties. For this, experimental techniques such as infrared spectroscopy and ellipsometry were used. The data show that samples are chemically stable up to 150°C, a point above which anhydride formation occurs, resulting in the loss of the conductive groups. A second order thermal transition was found at (95±5) °C for polymers containing 20% MAA, which shifts towards higher temperatures as the MAA content increases. In addition, the water stability was tested. While the membranes show considerable water uptake (over 35% at 60% MAA content), mechanical stability is lacking, resulting in rupture formation and partial dissolution. A possible route to overcome this issue is found in crosslinking, with the addition of 15% ethylene glycol dimethacrylate providing sufficient stability to the polymer.

Evaluation of Antifungal Activity of Methacrylic Acid incorporated in Conventional Heat-activated Resins

ABSTRACT Aim The aim of this study was to evaluate the antifungal activity of heat-activated denture base resins modified with different concentrations of methacrylic acid (MAA). Materials and methods Methyl methacrylate (MMA) monomer of heat-activated resins was modified with different concentrations of MAA (0, 15, 20, and 25%) for the preparation of specimens to evaluate antifungal activity of heat-activated resins. Prepared specimens were stored in distilled water at 37°C for 1 day and 1 week before the evaluation of microbial adhesion. Microbial adhesion of Candida albicans cells to acrylic samples was examined under light microscopy after Gram staining of all the acrylic samples. Data were subjected to one-way analysis of variance followed by post-hoc Tukey's honest significant difference test. A value of p &lt; 0.05 was considered to be statistically significant Results Addition of MAA to the MMA monomer was found to significantly reduce the adhesion of C. albicans for all the groups. Reduction of C. albicans cell adherence was found significant for all three groups (I, II, and III) as compared to control, both at 1 day (p &lt; 0.001) and 1 week (p &lt; 0.001) after storage in distilled water Conclusion Addition of MAA to conventional denture base formulations reduced the adhesion of C. albicans. This method of incorporating antifungal property to denture base resins can effectively be used to reduce denture stomatitis in elderly and immunocompromised patients. How to cite this article Gupta L, Aparna IN, Dhanasekar B, Bhat S, Ginjupalli K, Agarwal P. Evaluation of Antifungal Activity of Methacrylic Acid incorporated in Conventional Heat-activated Resins. World J Dent 2017;8(2):129-133.

Effect of isobutyl methacrylate and methacrylic acid eluted from chairside denture hard reliners on enzymatic cellular antioxidants: An in vitro study in human primary buccal mucosal fibroblasts.

Aim:This study was conducted with the objective to evaluate the cytotoxicity of monomers isobutyl methacrylate (IBMA) and methacrylic acid (MA) in human buccal mucosal fibroblast primary cell culture and to study their effect on cellular enzymatic antioxidants-glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT).Materials and Methods:The tissue for fibroblast cell culture was harvested from oral buccal mucosa of a healthy donor. Fibroblast cells were plated at a density of 1 × 104 cells per well in 96-well tissue culture plates. Cells were exposed to various concentrations of IBMA and MA. The cell viability and various enzyme activities were evaluated 24 h after exposure to the above treatments. All tests were done in triplicate. Cell viability was assessed by trypan blue dye exclusion assay and all enzyme activities were done using assay kits from Cayman Chemicals, Ann Arbor, USA.Results:At all concentrations tested a statistically significant decrease in viability was observed in IBMA- and MA-treated cells. Around 42% cells were viable at the highest test concentration of IBMA (80 μmol/L) and only 20% cells were viable at the highest dose (144 μmol/L) of MA exposure (P < 0.05). Dose-dependent decrease in the GPx and SOD activities was observed in cells treated with IBMA and MA (P < 0.05). CAT activity was not detectable in the controls. However, a fall in CAT activity was detected in cells exposed to IBMA and MA at all concentrations tested (P < 0.05).Conclusion:IBMA and MA leaching out from the chairside denture hard reliners are cytotoxic on human buccal fibroblast primary cell cultures. This could be due to the oxidative stress caused by the generation of reactive oxygen species which is evidenced by the fall in activities of antioxidant enzymes (GPx, SOD, and CAT) and cytotoxicity.

Effect of comonomer of methacrylic acid on flexural strength and adhesion of Staphylococcus aureus to heat polymerized poly (methyl methacrylate) resin: An in vitro study.

Aims and Objective:The purpose of the present study was to evaluate and compare flexural strength and Staphylococcus aureus adhesion of heat-activated poly (methyl methacrylate [MMA]) resin modified with a comonomer of methacrylic acid (MAA) and MMA monomer.Materials and Methods:Comonomer preparation was done with the addition of varying concentration of MAA (0, 15, 20, and 25 wt %) to the MMA of conventional heat-activated denture base resin to prepare the specimens. Prepared specimens were stored in distilled water at 37°C for 1 day and 1 week before the evaluation of flexural strength and microbial adhesion. Flexural strength was measured using a universal testing machine at a crosshead speed for 2 mm/min (n = 10). Microbial adhesion (colony-forming unit [CFU]) was evaluated against S. aureus using a quadrant streaking method (n = 5). Data were subjected to one-way ANOVA, and the significant differences among the results were subjected to Tukey's HSD test. P < 0.05 was considered statistically significant.Results:Addition of MAA to the MMA monomer was found to significantly reduce the adhesion of S. aureus for all the groups. Reduction of CFU of S. aureus was found be more significant for Group 3 as compared to control, both at 1-day (P < 0.001) and 1-week (P < 0.002) storage in distilled water. However, no statistically significant changes in the flexural strength were observed with the addition of MAA at 1-day (P = 0.52) and 1-week (P = 0.88) time interval.Conclusion:Addition of MAA to conventional denture base resin reduced the microbial adhesion without significantly affecting the flexural strength.

Synthesis of opaque and colored hollow polymer pigments

A parametric study was carried out to investigate the effects of process parameters on the properties of opaque and/or colored polymer pigment. The core was synthesized using methyl methacrylate (MMA), methacrylic acid (MAA), and ethylene glycol dimethacrylate, and the shell from styrene. The surfactant/water (S/W) ratio was changed between 0.56 and 1.46, and the best ratio was determined to be 0.97. The increase in the amount of MAA and the pH of the medium increases the diameter of the swollen particles. The hollows could form only when the fraction of MAA in the monomer mixture was above 10%, and pH ≥ 10. The opaque pigment with the largest diameter could be obtained at the S/W ratio of 0.97 and the MAA content of 20%, as 350 nm. It gave an opacity value of 93.8% when mixed with an acrylic resin at 50% by volume. The colored opaque polymer pigments were synthesized by adding copper phthalocyanine into the monomer mixture. The addition of 2% copper phthalocyanine yielded a green-blue color but 3% yielded blue color. The latter yielded a change in the lightness (ΔL*) by a value of −31.49, and a total color difference (ΔE*) of 30.05 compared with that of white opaque polymer pigment. POLYM. ENG. SCI., 57:913–920, 2017. © 2016 Society of Plastics Engineers

Ciprofloxacin-imprinted hydrogels for drug sustained release in aqueous media

In this study several ciprofloxacin (CFX) imprinted and non-imprinted hydrogels were prepared and evaluated as ocular drug delivery systems in aqueous media. 2-Hydroxyethyl methacrylate (HEMA) was used as a solvent and backbone monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linker, methacrylic acid (MAA) as a functional monomer and CFX as the template molecule. CFX-imprinted hydrogels (MIPs) were prepared applying different CFX:MAA molar ratios (1:16, 1:20 and 1:32) in feed composition of monomer solutions. Thermal polymerization was applied and hydrogels were synthesized in a polypropylene mold (0.4 mm thickness). Swelling and binding properties of hydrogels were evaluated in water. Release profile of the MIPs was evaluated in NaCl (0.9%) and artificial tears. The data showed that enhancing the MAA concentration, as a co-monomer, and using molecular imprinting improved binding properties of the synthesized hydrogels. The optimized MIPs with 400 mM MAA and CFX: MAA molar ratio of 1:20 and 1:16 showed the greatest affinity for CFX and the highest ability to control drug release. In vitro antibacterial activity of hydrogels was studied and demonstrated the effect of CFX-loaded hydrogels against Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) isolated from patients’ eyes. This study indicated antibacterial efficacy of CFX-loaded MIP hydrogels.

Design and Characterization of PVA–Methacrylic Acid Based Smart Polymeric System for Controlled Release of Metoprolol

In the present work covalently crosslinked smart polymeric system of hydrogel based on poly vinyl alcohol (PVA) and methacrylic acid (MA) was designed by free radical polymerization with different compositions using glyoxal (40 % water solution) as crosslinker. It was observed that swelling of hydrogel had a pronounced enhancing effect on increasing the concentration of MA due to availability of more ionized carboxylic groups of MA but produced an opposite effect on increasing the concentration of glyoxal owing to less porous structure. As far as PVA is concerned, swelling did not show significant effect on increasing the concentration of PVA. Hydrophilic polymer PVA rich in hydroxyl group pertained to be highly interactive with water. It was examined that the release of metoprolol tartrate decreased with increased concentration of glyoxal, but increased with increase in concentration of MA. PVA/MA hydrogel was characterized by Fourier transform infrared spectroscopy and X-ray diffraction to study the structure and crystallinity of hydrogel respectively. Morphology was studied through scanning electron microscopy. Furthermore differential scanning calorimetry and thermogravimetric analysis were also performed to characterize thermal stability. It may be concluded that the mechanism of drug release was mainly non-Fickian diffusion.

Radiation-induced grafting of acrylamide and methacrylic acid individually onto carboxymethyl cellulose for removal of hazardous water pollutants

Carboxymethyl cellulose hydrogels were synthesized by grafting of acrylamide (AAm) and methacrylic acid (MAAc) individually with different concentrations onto carboxymethyl cellulose (CMC) using direct radiation grafting technique. It was found that for both Poly(CMC/AAm) and Poly(CMC/MAAc), the grafting yield and grafting ratio increase with the increasing monomer concentration. Also, it is noted that both grafting ratio and grafting yield of Poly(CMC/AAm) are higher than that of Poly(CMC/MAAc). The effect of different monomer concentrations on gel (%) and swelling behavior was studied. It is found that the increasing monomer concentration increases gel (%). For Poly(CMC/AAm) hydrogels, the swelling behavior decreases with increasing AAm concentration due to high crosslinking hydrogel formation, while as MAAc content increases, swelling behavior increases up to Poly(CMC/MAAc) 1:25 wt%. Swelling kinetics and diffusion mechanism indicate that the water penetration obeys non-Fickian transport mechanism. The structures and properties of the original CMC and the prepared Poly(CMC/MAAc) and Poly(CMC/AAm) were characterized using different analytical tools such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscope (SEM). This study provides a solution to the discharge of different pollutants from wastewater. The adsorption capacity of Poly(CMC/MAAc) and Poly(CMC/AAm) hydrogels toward heavy metals, Cu+2 and Co+2, dyes such as acid blue dye and methyl green, and organic contaminants such as 4-chlorophenol and 2,4-Dichlorophenoxy acetic acid has been investigated.