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AbstractThe Guar Gum Xanthate based hydrogel GGmX-g-poly(AA-co-HEMA) has been successfully synthesized by using the graft copolymerization of two monomers, acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) hydrogel. The synthesis follows the free-radical graft polymerization method. UV-visible spectroscopy (UV), Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Point zero charge (PZC), and field emission scanning electron microscopy (FESEM) were employed for the characterization of the synthesized hydrogel. This hydrogel has shown a high swelling ratio of 430.2 g/g and retention of 75.82% in distilled water which is a notable result. By using GGmX-g-poly(AA-co-HEMA) hydrogel, the maximum percentage of heavy metal ions removal from wastewater was found to be 98.5(±1.5)% and 97.1(±1.5) at optimum pH 6 and 6.5 for Cu2+ and Ni2+ solutions respectively. The Langmuir adsorption isotherm fits best for the adsorption data indicating a monolayer adsorption with maximum adsorption capacity of 423.72 (±26.1) mg/g and 404.85 (±31.4) mg/g for Cu2+ and Ni2+ ions respectively. The pseudo-second-order kinetic model provides the most accurate depiction of adsorption kinetics with rate constant 9.1 × 10−4 (±1.37×10−4)g/(mg.min) for Cu2+ and 8.3 × 10−4 (±1.24×10−4)g/(mg.min) for Ni2+ ions, respectively. The negative ΔG value (-4.75 kJ/mol for Cu2+ and −3.26 kJ/mol for Ni2+ ions) and positive value of ΔH (57.55 (±5.41) kJ/mol for Cu2+ and 40.60(±5.37) kJ/mol for Ni2+ ions) suggested the process to be spontaneous, endothermic, and feasible. It has been found that the hydrogel has excellent regenerative capacity with the % adsorption has been found to be 84.8% for Cu2+ and 82.4% for Ni2+ ions for the fifth cycle. [ABSTRACT FROM AUTHOR]

A new separation technology, three-phase crystallization (TPC), was utilized to purify acrylic acid (AA) from a binary liquid mixture comprising AA and propionic acid (PA). The solid–liquid equilibrium data of AA/PA mixture reported in the literature were adopted to recover the activity coefficients of the liquid mixture; and, subsequently, the vapor–liquid equilibrium conditions of AA/PA mixture were predicted using Raoult's law and the Wilson equations for the recovered activity coefficients. The reported solid–liquid equilibrium data and the predicted vapor–liquid equilibrium conditions were coupled to determine the three-phase transformation conditions of AA/PA mixture, which were employed to conduct the batch TPC experiments. Upon conclusion of the TPC, the yield and purity were measured to estimate the amount of the AA crystals and volume of the liquid mixture retained in the overall final product, respectively. [ABSTRACT FROM AUTHOR]

AbstractConventional wound dressings used in trauma treatment have a single function and insufficient adaptability to the wound environment, making it difficult to meet the complex demands of the healing process. Stimuli-responsive hydrogels can respond specifically to the particular environment of the wound area and realize on-demand responsive release by loading active substances, which can effectively promote wound healing. In this paper, BC/PAA-pH responsive hydrogels (BPPRHs) were prepared by graft copolymerization of acrylic acid (AA) to the end of the molecular chain of bacterial cellulose (BC) network structure. Antibacterial pH-responsive ‘smart’ dressings were prepared by loading curcumin (Cur) onto the hydrogels. Surface morphology, chemical groups, crystallinity, rheological, and mechanical properties of BPPRHs were analyzed by different characterization methods. The drug release behavior under different physiological conditions and bacteriostatic properties of BPPRH-Cur dressings were also investigated. The results of structural characterization and performance studies show that the hydrogel has a three-dimensional mesh structure and can respond to wound pH in a ‘smart’ drug release capacity. The drug release behavior of the BPPRH-Cur dressings under different environmental conditions conformed to the logistic and Weibull kinetic models. BPPRH-Cur displayed good antimicrobial activity against common pathogens of wound infections such as E. coli, S. aureus, and P. aeruginosa by destroying the cell membrane and lysing the bacterial cells. This study lays the foundation for the development of new pharmaceutical dressings with positive health, economic and social benefits. [ABSTRACT FROM AUTHOR]

Transformation of methyl lactate to acrylic acid was investigated over Ca3(PO4)2, Ca2(P2O7) and their mixture in the temperature range of 250-425 °C. The initial concentration of methyl lactate in water was varied from 2 wt% to neat methyl lactate. The results showed that these phosphate catalysts did not contain any measurable amounts of either acid sites or basic sites. The best catalyst was Ca3(PO4)2 giving 62% selectivity to acrylic acid at 75% conversion at 400 °C using GHSV of 95280 h−1 and 2 wt% methyl lactate in the initial feed. This catalyst exhibited larger surface area in comparison to Ca2(P2O7). Elemental analysis revealed that some Ca leaching occurred during reaction, while in case of Ca2(P2O7) the calcium leaching was 3.4 fold higher than observed for Ca3(PO4)2. Long-term results over Ca3(PO4)2 showed that extensive catalyst deactivation occurred during the first 11 h time-on-stream, after which the activity dropped only slightly. In addition to kinetic studies with different parameters, also, kinetic modeling was performed and the activation energies for formation of different products were determined over different catalysts. [ABSTRACT FROM AUTHOR]

AbstractA fluid loss additive (named AAMN) for cementing ultra-deep reservoirs at high temperature (210 °C) was prepared by a free radical copolymerization method using 2-acrylamido-2-methylpropane sulfonic acid (AMPS), acrylamide (AM), acrylic acid (AA), and N-vinyl-2-pyrrolidinone (NVP) as monomers. Filtration tests at 210 °C demonstrated that AAMN reduced the amount of fluid loss by 22% in fresh cement slurry, 23% in 18 wt% NaCl cement slurry, and 16% in 36 wt% NaCl cement slurry compared to AAM (without NVP) when both were added at 6% bwoc ("bwoc" denotes the addition by the weight of the cement). The pore structure was analyzed using the Brenner-Emme-Teller (BET) method and environmental scanning electron microscopy (ESEM), confirming that AAMN could be adsorbed onto the cement particles surfaces, filling the pores and blocking fluid loss channels. The degradation temperatures of the two copolymers were tested by thermogravimetric analysis (TGA-DTGA) and the molecular dynamics behavior of two Amorphous Cell (AC) models (the amorphous structures with randomly arranged Ca2+, Cl−, Na+ and H2O with the AAMN or AAM) built by Materials Studio 7.0 software, were compared: the introduction of five-element NVP side chains didn’t significantly improve the thermal stability of the AAMN relative to the AAM, but resulted in the AAMN molecular chain maintaining a stable geometry at a temperature of 483 K (210 °C). The AAMN also showed more adsorption groups (–SO3− and –COO−) at the high temperatures, which allowed the AAMN to form a dense "network structure" with Ca2+ and H2O molecules, thus effectively blocking the channels for water molecule loss from the cement slurries. [ABSTRACT FROM AUTHOR]

The current effort in environmental remediation is aimed at removing iodine-131 radionuclide from radioactive liquid waste produced by an Egyptian nuclear power plant using some synthesised alginate derivatives. Two different copolymers, namely sodium alginate poly (acrylic acid) (P1) and sodium alginate poly (acrylic acid-methacrylic acid) (P2), are prepared using gamma radiation. The ability of these polymers to remove 131I radionuclide as sorbents has been investigated. The synthesised polymers exhibit excellent adsorption performance for 131I ions, and the adsorption equilibrium requires only 30 min, which reveals that the sorption process is kinetically faster than most of the other materials reported previously. The removal percents for 131I radionuclide at a pH of 3.0 at room temperature on P1 and P2 are 77.7% and 84.2%, respectively. The sorption capacities of the two polymers demonstrate that P2 > P1, with capacities of 67.9 and 58.5 mg/g, respectively. Four linear kinetic models are investigated: pseudo-first order, pseudo-second order, Elovich, and Weber–Morris models. Regarding their calculated parameters, these models indicate that the adsorption process of I-ions on both P1 and P2 is controlled by chemisorption. Four equilibrium isotherm models (Redlich-Peterson, Langmuir, Freundlich, and Harkin-Jura) are investigated, revealing that the adsorption process is a monolayer and multilayer process on a heterogeneous surface. [ABSTRACT FROM AUTHOR]

Photonic crystal structural color is a novel method in the field of colored coating on the surface of wood products. However, the subjective brightness of photonic crystal structural colored wood products under different color temperature light sources has not been studied. In this study, poly(styrene-methyl methacrylate-acrylic acid) latex microspheres with different diameters were used to construct photonic crystal coatings on wood surface. The subjective brightness psychological quantity under different color temperature light sources was obtained. Combined with the optical properties of the coatings, the correlation between the physical optical properties of the photonic crystal coating, the color temperature of the light source and the subjective brightness of the coating was obtained. The photonic crystal coating in the near red visible light wavelength range had higher subjective brightness under low color temperature light source, and coating in the near purple visible light wavelength range had higher subjective brightness under high color temperature light source. The subjective brightness of the photonic crystal coating was very closely related to the light source color temperature and closely related to the reflectivity of the coating. This study expands the research on the optical properties of photonic crystal structure colored wood products. [ABSTRACT FROM AUTHOR]

UV water-based inks have disadvantages such as slow curing speed and low degree of crosslinking. In this paper, the copolymer P(MMA-r-HEMA) was prepared by traditional free radical polymerization using methyl methacrylate (MMA) and hydroxyethyl methacrylate (HEMA) as monomers, and the copolymer P(MMA-r-HEMA) was modified by acrylic acid (AA) to synthesis completely water-soluble acrylic prepolymer P(MMA-r-HEMA)-g-AA. Triethylenetetramine reacted with glycidyl methacrylate (GMA) to yield a multifunctional reactive diluent TGMA. Secondly, acrylic prepolymer P(MMA-r-HEMA)-g-AA, multifunctional reactive diluent TGMA and photoinitiator were used to prepare water-based UV curable ink. The influence of the type and quality of photoinitiator, the relative molecular weight and mass fraction of P(MMA-r-HEMA)-g-AA, the number of functional groups and mass fraction of TGMA on the UV ink curing speed and the wear resistance of the ink film were discussed. When the mass fraction of the photoinitiator TPO was 1%, the number-average relative molecular mass of the prepolymer was 1.67 × 104 g/mol and the mass fraction was 60%, the number of functional groups of the reactive diluent was 6 and the mass fraction was 40%, the light curing of UV water-based ink was completed in 0.1 s, and the mass loss after 50 times abrasion was 0.2–0.4%. [ABSTRACT FROM AUTHOR]

Polyphenolic compound-modified hydrogel wound dressings with excellent wet tissue adhesion, antimicrobial properties, stretchability, and full-thickness skin healing properties are still extremely rare so far. Polyphenolic compounds such as tannic acid or dopamine can improve the antibacterial and bioadhesive properties of hydrogels, and are also polymerization inhibitors for free radical polymerization. In this study, polyacrylic acid (PAA) aqueous solution was first synthesized, and then antibacterial PAA-TA hydrogel was prepared by mixing it with tannic acid (TA) and the crosslinker 1,6-hexanediol bis(2-methyl-1-propionic acid azide) (HBMAP). This method avoids the hindrance of the phenolic hydroxyl groups in TA on acrylic acid polymerization, and we were able to obtain a series of TA hydrogels (in the range of 0–15 wt.%. We applied these PAA-TA hydrogels to wound dressings and found that they had excellent adhesion to biological tissues, and the tensile strength and elongation at break of PAA-TA hydrogels with 15 wt.%TA content were as high as 1.72 MPa and 1446.3% in tensile strength evaluation. In addition, microbiological analysis showed that wound dressings had significant antimicrobial activity against Staphylococcus aureus and Escherichia coli. In vitro wound healing experiments confirmed that the wound dressing was biocompatible and could significantly promote the healing of full-thickness skin defects in the guinea pig model. Our work describes an injectable, self-healing, antimicrobial hydrogel that may have promising clinical applications as a wound dressing material. [ABSTRACT FROM AUTHOR]

Humidity sensors play a critical role in diverse fields such as agricultural production, medical equipment, and weather forecasting. However, the majority of existing humidity sensors rely on batteries or are relatively costly to construct. In this study, a simple, efficient, and battery-free visual humidity sensor was developed by combining cholesteric liquid crystal (CLC) with acrylic acid (AA) and subsequently curing it to form an interpenetrating polymer network (IPN) film. The IPN film changes colour with relative humidity (RH). Moreover, it has been confirmed that the film exhibits excellent repeatability, and its performance remains relatively unaffected by temperature fluctuations. Additionally, the relationship between film thickness and response time is explored in this research. Through orthogonal experiments involving various proportions of CLC, the study also scrutinises the influence of each component on the humidity response performance of the IPN films. During the transition from 40% RH to 90% RH, IPN film sample 3 experienced a remarkable redshift of 123.05 nm in the reflected wavelength. As for sample 9, its humidity response demonstrated an outstanding linearity of 0.9986. Consequently, the experimental outcomes provide strong evidence that this IPN film exhibits superior humidity response capabilities and holds considerable promise for practical applications. [ABSTRACT FROM AUTHOR]

Nanostructured material chitosan polymer grafted with styrenesulphonate and acrylic acid as ion-imprinted polymer have been synthesised and developed by a new method that provides control over the size and chemical structure. The utilisation of high-intensity ultrasound has been investigated for the synthesis of a nanostructured polymer that is often unavailable by conventional methods. The preparation of ion-imprinted polymer of chitosan as a backbone with grafting of sodium styrene sulphonate and acrylic acid are used for the removal of Pb2+in the presence of Zn2+ as interference ion where the maximum sorption capacities at 90 minutes and pH 4.0 are 82 and 30 mg/g, respectively. In the mean time, regeneration does not have a severe effect on the capacity of IIP. That mean the capacity decreases by 4% after 3 times regeneration.The results showed that ion imprinted polymer can be used with higher efficiency and selectivity in the presence of zinc. The kinetic studies were elaborated shows the corresponding of the theoretical and practical capacity following the models pseudo-second-order and elovich kinetic models and the results of thermodynamic parameters demonstrates that the sorption process is endothermic nature in all cases as the enthalpy equal 26.4 KJ/Mol and the free energy is −1.2 KJ/Mol. Finally, more disorder is associated with the sorption process and reflects good affinity of Pb2+ ion towards the IIP. [ABSTRACT FROM AUTHOR]

In this work, we reported a novel emulsion copolymerization of vinyl chloride monomer (VCM) with amphipathic monomer poly (ethylene glycol) methyl ether methacrylate (PEGMA) by using sodium dodecyl sulfate (SDS) as emulsifier and K2S2O8/NaHSO3 as redox initiator. Owing to the multifunctionality of PEGMA that can serve as co-monomer and 'emulsifier', the emulsion copolymerization is achieved successfully and the interesting results demonstrate quite different features such as:(1) the stable P[(VC)-co-(PEGMA)] latex is obtained only when the mass ratio of PEGMA > 10% (to total monomer mass), (2) a small amount of ionic emulsifier SDS is required to achieve a stable latex, and (3) the mechanism of the micellar formation is different from the typical emulsion polymerization. Unexpectedly, the obtained copolymer formed high content of gel fraction which is mainly caused by the chain transfer reaction of the PVC growth chain radical to the hydrogen atom of the methylene from alkoxy (-OCH2CH2-) of the PEGMA oligomer chain. However, it could be inhibited effectively by the addition of chain transfer agent 2-mercaptoethanol (2-MCE). Subsequently, the properties of as-obtained P[(VC)-co-(PEGMA)] copolymer are evaluated carefully and it exhibited unique features such as self-plasticization, lower Tg (decreased from 83.1 to 59.6 °C), higher heat resistance (increased from 270 to 290 °C), hydrophilic, and high transparent in comparison to pure PVC. These outstanding features of the P[(VC)-co-(PEGMA)] copolymer offered a potential route for the functional modifications of PVC and broadened its further use. [ABSTRACT FROM AUTHOR]

Polyhydroxyalkanoates (PHAs) are biopolymers that are produced within the microbial cells in the presence of excess carbon and nutrient limitation. Different strategies have been studied to increase the quality and quantity of this biopolymer which in turn can be utilized as biodegradable polymers replacing conventional petrochemical plastics. In the present study, Bacillus endophyticus, a gram-positive PHA-producing bacterium, was cultivated in the presence of fatty acids along with beta-oxidation inhibitor acrylic acid. A novel approach for incorporating different hydroxyacyl groups provided using fatty acids as co-substrate and beta-oxidation inhibitors to direct the intermediates to co-polymer synthesis was experimented. It was observed that higher fatty acids and inhibitors had a greater influence on PHA production. The addition of acrylic acid along with propionic acid had a positive impact, giving 56.49% of PHA along with sucrose which was 1.2-fold more than the control devoid of fatty acids and inhibitors. Along with the copolymer production, the possible PHA pathway functional leading to the copolymer biosynthesis was hypothetically interpreted in this study. The obtained PHA was analyzed by FTIR and 1H NMR to confirm the copolymer production, which indicated the presence of poly3hydroxybutyrate-co-hydroxyvalerate (PHB-co-PHV), poly3hydroxybutyrate-co-hydroxyhexanoate (PHB-co-PHx). [ABSTRACT FROM AUTHOR]

Tissues are highly three-dimensional structure complexes composed of different cell types and their interactions. One of the main challenges in tissue engineering is the inability to produce large, highly perfused scaffolds in which cells can grow at a high cell density and viability. Poly(dimethyl siloxane) (PDMS) is used as a flexible, biocompatible cell culture substrate with tunable mechanical properties. However, its fragility and hydrophobicity still pose a challenge. Here, we present a new strategy for the three-step one-pot synthesis of novel biocompatible hydrophilic copolymers containing siloxane units. In the first step, free radical copolymerization of acrylic acid (AA), butyl methacrylate (BMA), and 2-hydroxyethyl methacrylate (HEMA) was carried out in dioxane (DO) solution in the presence of 2,2′-azodiisobutyronitrile (AIBN). In the second step, the copolymers were modified with diepoxypropoxypropyl-terminated polydimethylsiloxane (DE-PDMS), and in the third step, the copolymers were additionally modified with glycidyl methacrylate (GMA). The modified copolymers were characterized by FTIR, NMR spectroscopy and elemental analysis. Films of modified copolymers were prepared by UV curing. SEM studies revealed microphase separated morphology with distribution of PDMS domains. The mechanical properties of the films depended on the amount of incorporated silicone modifier. The films were more hydrophilic than PDMS films. All novel copolymers showed high biocompatibility. [ABSTRACT FROM AUTHOR]

Lung metastatic breast cancer is a leading cause of cancer-related death in women and difficult to treat due to non-specific drug delivery. Herein a sequential targeting dual-responsive magnetic nanoparticle was fabricated, where Fe3O4 nanoparticle was used as magnetic core, then sequentially coated with tetraethyl orthosilicate, bis[3-(triethoxy-silyl)propyl] tetrasulfide, and 3-(trimethoxysilyl) propylmethacrylate to afford -C = C- on the surface for further polymerisation with acrylic acid, acryloyl-6-ethylenediamine-6-deoxy-β-cyclodextrin using N, N-bisacryloylcy- stamine as cross-linker, obtaining pH/redox dual-responsive magnetic nanoparticle (MNPs-CD) to delivery doxorubicin (DOX) for suppressing lung metastatic breast cancer. Our results suggested DOX-loaded nanoparticle could target the lung metastases site by sequential targeting, in which they first be delivered to the lung and even the metastatic nodules through size-driven, electrical interaction, and magnetic field-guided mechanisms, then be effectively internalised into the cancer cells followed by intelligently triggering DOX release. MTT analysis demonstrated DOX-loaded nanoparticle exhibited high anti-tumour activity against 4T1 and A549 cells. 4T1 tumour-bearing mice were employed to confirm the higher specific accumulation in lung and improved anti-metastatic therapy efficiency of DOX by focussing an extracorporeal magnetic field on the biological target. Our findings suggested the as-proposed dual-responsive magnetic nanoparticle offered a prerequisite to inhibit lung metastasis of breast cancer tumours. [ABSTRACT FROM AUTHOR]

An azo-type thermosensitive crosslinking agent was prepared from azobisisobutyramidine hydrochloride (V-50) and maleic anhydride. It is then copolymerized with acrylamide (AM) and acrylic acid (AA) to prepare thermosensitive self-degradation microgel. The microgel particles are uniformly dispersed in the aqueous solution in the form of particles. Water absorption and swelling experiments of microgel showed that the water absorptivity of microgel decreased with the increase of salinity. And the microgel have the best water absorptivity under a neutral environment. The results of microgel degradation experiments showed that the higher the temperature, the shorter the degradation time, and the degradation is complete within 5 h at 100 °C. The solid residue measured by the degradation liquid is almost 0, indicating that the microgel can be thoroughly degraded at high temperature. The polymer solution after degradation can be measured by gel chromatograph and the average molecular weight is Mn=1.9 × 105g/mol. And the swelling and degradation mechanism were summarized. [ABSTRACT FROM AUTHOR]

The behavior of different polymerizable surfactants was investigated to improve the water-resistance of pressure-sensitive adhesives (PSAs) based on acrylic acid (AA) and n-butyl acrylate (n-BA). Differences in the adhesion properties were found according to the chemical structure and the critical micelle concentration of the polymerizable surfactant, especially when compared to the non-polymerizable reference surfactant (Dowfax 2A1). The polymerizable surfactants with a branched structure resulted in more gel content and higher glass transition temperature in the adhesive. In general, the peel resistance and tack properties decreased with the use of polymerizable surfactants in the PSA formula. However, increased shear resistance was observed with respect to the PSA adhesive synthesized with the reference surfactant. Furthermore, the adhesives made with higher molecular weight polymerizable surfactants resulted in higher shear elastic modulus, shear strength, and deformation energy than the rest of the PSA adhesives. On the other hand, as expected, all the polymerizable surfactants studied contributed to the improved water resistance of the PSA compared to the reference PSA prepared with a conventional surfactant. The covalent bond formed between the polymer and the surfactant limited the migration of the surfactant towards the air-film interface thus reducing the formation of water entry pathways. The polymerizable surfactants with linear molecular structure showed the best water resistance performance. [ABSTRACT FROM AUTHOR]

Concrete usually possesses advantages of high compressive strength but weaknesses of low tensile strength originating from the intrinsic brittleness of cement hydrates. Here we propose a method of in situ copolymerization of monomers that use acrylic acid (AA) and acrylamide (AM) to restrain the brittleness of cement hydrates by in situ copolymerization during cement hydration and to enhance the mechanical strength of the cement matrix. Cement pastes with reinforced flexural strength and compressive strength can be obtained by modulating the fraction of AA-AM copolymer. With the polymerization reaction, a polymer skeleton was constructed in the cement matrix, followed by crosslinking with cement hydrates by the coordination between metal ions (Ca2+ and Al3+) and carboxy groups, enhancing the flexural strength and toughness of cement pastes. Our work offers a straightforward method to reduce the intrinsic brittleness of cement hydrates, providing a facile access to cementitious materials with improved flexural performance. [ABSTRACT FROM AUTHOR]

Inter-macromolecular interaction between uncharged polymers in aqueous solutions can be influenced by concentration of polymer, solvent quality, molecular weight, solution pH, temperature, salt concentration and type of salt. Atomistic molecular dynamics simulations of aqueous NaCl solution containing poly(acrylic acid) and poly(ethylene oxide) are presented. The size of the polymer chains decreases with an increase in salt concentration resulting from water becoming a poor solvent which enhances compositing of polymers. A close pair is formed between carboxylic hydrogen (−COOH) and ether oxygen (−O−) of the polymer at high salt concentration. The change in structure of the PAA/PEO complex is analysed using simulated SAXS and SANS profiles. The solubility of chains decreases and attains the minimum energy conformation at a particular salt concentration. The solvent accessible surface area (SASA) of the complex at higher salt concentration is less as compared to the lower. Increase in salt concentration enhances the cooperative interaction via hydrogen bonding between PAA and PEO and weakens the polymer-water-hydrogen bonding. The net result is a decrease in solubility of these polymers and thermodynamically stable polymer-polymer complex is formed at higher salt concentrations. Simulation results are in agreement with available experimental data in literature. [ABSTRACT FROM AUTHOR]

Plastic antibodies can be used for in vitro neutralization of biomacromolecules with different fragments due to their potential in separation, purification, chemical sensor, catalysis and drug production studies. These polymer nanoparticles with binding affinity and selectivity comparable to natural antibodies were prepared using functional monomer synthesis and copolymerization of acrylic monomers via miniemulsion polymerization. As a result, the in vitro cytotoxic effect from diphtheria toxin was reduced by MIPs. In vitro imaging experiments of polymer nanoparticles (plastic antibodies) were performed to examine the interaction of diphtheria toxin with actin filaments, and MIPs inhibited diphtheria toxin damage on actin filaments. The enzyme-linked immunosorbent assay (ELISA) was performed with plastic antibodies labeled with biotin, and it was determined that plastic antibodies could also be used for diagnostic purposes. We report that molecularly imprinted polymers (MIPs), which are biocompatible polymer nanoparticles, can capture and reduce the effect of diphtheria toxic and its fragment A. [ABSTRACT FROM AUTHOR]

Acrylic acid (AA) and Acrylamide (AM) are copolymerised to produce copolymer of Poly-acrylic acid-co-acrylamide (PAA) in the aqueous solution of Polyvinyl alcohol (PVA). Both the polymers PVA and PAA were cross-linked in situ by glutaraldehyde and N, N O-methylene bis acrylamide (MBA) respectively using 2 mass% of polymer basis for both of them. Thus, three different full interpenetrating network (FIPN) hydrogels were synthesised varying the mass ratio of PVA to PAA. The hydrogel of PVA: PAA = 1:0.50 composition designated as PAA50 found competitive for separating Malachite green from its 50 ppm aqueous solution by adsorption compared to the other two. PAA50 was further modified by incorporating 2, 5, 8 and 10 mass% nano size sodium monomontellite filler and produced four filled FIPN hydrogels designated as PAA52, PAA55, PAA58 and PAA510, respectively. These four nano-filled FIPN hydrogels along with unfilled PAA50 and pure nano size sodium monomontellite were used for adsorption in same dye solution of 5, 10, 25, 50, 75 and 100 ppm concentrations and different pH of 4, 7, 9, 10 & 11. Highest 98.039% dye removal was done by PAA58 from 75 ppm feed at 9 pH. 93.7% recovery was observed at 3 pH in desorption study. [ABSTRACT FROM AUTHOR]

By the esterification of benzoic anhydride (BA) with polyoxyethylene ether (HPEG), the modified macromonomer (BA-HPEG) with benzoate of HPEG was prepared. Then, BA-HPEG and HPEG were copolymerized with acrylic acid (AA) with an alkyd ratio of 2:1 to obtain three novel polycarboxylate superplasticizer BA-PCE-10, BA-PCE-20 and BA-PCE-30 with good flow retaining behaviors of cement mortars. The effects of the benzoate content in the copolymers on adsorption, dispersion, Zeta potential and hydrodynamic radius for cement suspensions were investigated to elucidate the governing dispersing mechanism. The absorption of the modified copolymers on the cement surfaces was controlled by COO― and hydrophobic phenyl content in copolymers and polymer conformation in solution. The fluidity of cement slurry increases with the adsorbed amount to increase dispersion effect. The copolymers grafted with benzoate exhibited a high dispersion performance than that of the unmodified molecule, which could be explained as the hydrophobic modified polycarboxylate superplasticizer mainly dispersing cement particles by the main repulsion of steric hindrance and electrostatic repulsion, so as to improve the dispersion performance of cement. The study shows that the flow retaining behaviors of polycarboxylate superplasticizer can be significantly improved by BA modified with hydroxyl-terminated of the side chains of polycarboxylic superplasticizer. [ABSTRACT FROM AUTHOR]

Thermo-responsive hydrogels display swell-collapse behavior in response to changing temperature. While the hydrogels themselves have many applications such as environmental and chemical separations, the hydrogel can be incorporated within a membrane substrate to improve its mechanical properties and expand the opportunities for development and implementation. The present work describes synthesis of positive volume transition temperature responsive poly(acrylamide-co-acrylic acid) hydrogels on cellulose paper substrates. Effects of factors including co-monomer ratios, degree of crosslinking and mass loading are assessed for Series A random copolymer hydrogels in terms of permeability response. Examination of the membranes is then extended to investigate inter-penetrating networks (IPN) between acrylamide and acrylic acid homo-polymer hydrogels. Series B membranes explore the impact of nonpolar ligands on temperature response through addition of butyl methacrylate co-monomer. For both random copolymer and IPN hydrogel membranes, mass loading dominates permeability performance, though certain criteria must be met. Performance of the Series A membranes was found to be ideal when monomer ratio was 1:1 and there was a lower degree of crosslinking. Addition of butyl methacrylate did not appear to have a consistent impact on the membrane response, appearing to be tied to the degree of crosslinking for random copolymer hydrogel coatings. [ABSTRACT FROM AUTHOR]

The present work described a novel synthesis of spiro[indoline-3,3′-pyrazol]-2-one derivatives 2, 4, 5, and 7 via a one-pot reaction of chalcones or β-aroyl acrylic acid 1a–c, isatin, and hydrazine derivatives e.g. hydrazine hydrate, methyl hydrazine, phenylhydrazine or acetohydrazide in sonicated reaction condition. The unexpected product 1,3-oxazino[3,2-a]indol-10-yl-ethanone derivative 6 can be generated instead of N-acetyl spiro[indoline-3,3′-pyrazol]-2-one as desired. Also, the Spiropyrazole-fused furanone and pyridazinone ring can be made. Owing to their unique 3-dimensional structures, spirooxindoles have been found as lucky chemotypes for antiviral drug enhancement in an attempt to achieve these spiropyrazole derivatives 2–10 with hydrophobic groups. Furthermore, the density functional theory (DFT) was used to elucidate the electronic and structural features of spiropyrazole derivatives and their reactive species, which supports the proposed mechanism of antibacterial and antiviral capabilities. [ABSTRACT FROM AUTHOR]

The adsorption of retarders on the surface of cement minerals is the main reason for the delayed cement hydration and the prolonged thickening time of oil well cement. This paper studied the adsorption of carboxyl-containing monomers on calcium silicate (C3S) with first-principle calculations based on density functional theory (DFT). The geometric structure was optimized, and the bond length, adsorption energy, charge transfer, charge density difference and partial density of states (PDOS) were calculated. The results indicated that the four carboxyl-containing monomers (acrylic acid, citraconic acid, itaconic acid, and maleic acid) all had strong adsorption energy, and they were ranked in the following order: itaconic acid > maleic acid > citraconic acid > acrylic acid. In addition, the charge density difference and PDOS results proved the strong adsorption. The charge density of the area between the O atom of the carboxyl group and the Ca atom on the C3S (040) surface increased. The overlapping of peaks and the hybridization occurred between Ca 3d and O 2p orbitals. This study deepens the understanding of the retarding mechanism on oil well cement. [ABSTRACT FROM AUTHOR]

Hydrogels are widely used in biomedical engineering, which often require matched mechanical properties to meet specific demands. Recently, numerous research studies have contributed to tissue engineering hydrogels by soaking strategies to obtain designed properties. Herein, a strategy to fabricate poly(vinyl alcohol)/poly(acrylic acid)-ammonium sulfate (PVA/PAA-AS) hydrogel by successively soaking an aqueous PAA solution and (NH4)2SO4 solution based on the synergy of multiple hydrogen bonding and Hofmeister effect is reported, which exhibits remarkable comprehensive mechanical properties: rigidity (elastic modulus: 0.7–3.6 MPa), strength at break (tensile stress: 3.2–12.0 MPa ; strain 320–650%), and toughness (fracture energy: 4.5–30.0 MJ m − 3 ). Besides, PVA/PAA-AS hydrogel with unique spring-like microstructure exhibited super-resilience in 30% strain range by energy-transforming mechanism. Compared with pure PVA hydrogel, PVA/PAA-AS hydrogel has the equal excellent cytocompatibility. Therefore, PVA/PAA-AS hydrogel with high strength, modulus, toughness, super-resilience and excellent biocompatibility has potential applications in the soft tissue engineering field such as muscles, tendons, and ligaments. [ABSTRACT FROM AUTHOR]

The acrylic acid treated rattan fiber reinforced epoxy (RF/Epoxy) composite has been fabricated by taking various weight percentages (5, 10, 15, 20, and 25 wt%) of fibers using hand layup followed by compression molding technique. The optimum fiber loading has been determined by regression analysis and it is found that 18 wt% of rattan fiber gives maximum tensile strength. The interaction of rattan fiber with epoxy matrix has been studied by Fourier transform infrared spectroscopy and X-ray diffraction. Scanning electron microscope (SEM) has been used to study the morphology of chemically modified rattan fiber and RF/Epoxy composite. The mechanical, thermal, and dynamic mechanical thermal properties of 18 wt% RF/Epoxy composite have been studied as per ASTM standards. From the results, it is observed that RF/Epoxy composite gives best properties at optimum (18 wt %) fiber loading. The maximum tensile strength and flexural strength of the composite are found to be 47.5 and 121 MPa, respectively, which is better in comparison to other natural fiber composites used for manufacturing different automobile body parts. Hence, it can be concluded that 18 wt% RF/Epoxy composite can be considered as a potential candidate for automotive body parts. [ABSTRACT FROM AUTHOR]

Acrylic acid (AA) nanocomposite hydrogels (NCH) containing different kinds of SiO2 nanoparticles were prepared by way of free radical polymerization. The polymerization conditions were optimized considering the initiator and monomer concentrations in the mixture, as well as the reaction temperature and time. SiO2 nanoparticles were used in original (neutral), NH2 modified (hydrophilic) and perlite forms. Nanocomposite hydrogels that contain NH2 modified nano-SiO2 were found to present swelling values higher than those of the original acrylic acid nanocomposite hydrogel and the nanocomposite hydrogel that contain original SiO2. AA-perlite nanocomposite hydrogels were used to achieve the best thermal stability, although the perlite-doped hydrogels exhibit less swelling due to the large particle size of perlite and its lower SiO2 content. FESEM and mapping analyses were conducted to verify the incorporation of SiO2 nanoparticles into the hydrogel structure. Amorphous structures were determined by an XRD analysis. Thermal stability of hydrogels was measured by TG-DTA. The thermal stabilities of NH2-modified SiO2- and perlite-doped nanocomposite hydrogels were found to be higher than those of plain hydrogel and original SiO2-doped nanocomposite hydrogels. [ABSTRACT FROM AUTHOR]

This study aimed to characterize the immobilization of the novel JIChis-2 peptide on the Ti-6Al-4V alloy, widely used in the biomedical sector. The antimicrobial activity of JIChis-2 was evaluated in the Gram-negative bacterium E. coli. Its immobilization occurred by inducing the formation of covalent bonds between the N-terminus of the peptides and the surface previously submitted to acrylic acid polymerization via the PECVD technique. Coated and uncoated surfaces were characterized by FTIR, AFM, SEM and EDX. Studies of global and localized corrosion were carried out, seeking to explore the effects triggered by surface treatment in an aggressive environment. Additionally, the ability of the functionalized material to prevent E. coli biofilm formation evidenced that the strategy to immobilize JIChis-2 in the Ti-6Al-4V alloy via PECVD of acrylic acid resulted in the development of a functional material with antibiofilm properties. [ABSTRACT FROM AUTHOR]

Acid treated locally available Bijoypur white clay was exfoliated with dodecyl amine to facilitate in-situ polymerisation of acrylic acid (AA) using N, N′‐methylenebisacrylamide (MBA) crosslinker and ammonium persulphate as the initiator for the preparation of a novel adsorbent. In order to obtain poly(acrylic acid)-graft-modified clay composite (PAA-g-MC), the growing PAA chain was 'grafted onto' the modified clay surface. The structural properties of the composite adsorbent were studied by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray fluorescence (XRF), and scanning electron microscope (SEM). Thermal properties of the composites were measured by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The effect of different process parameters such as pH of dye solution, contact time, initial concentration of dye, and adsorbent amount on the removal efficiency of methylene blue (MB) from aqueous solution was evaluated by batch experiments. Characteristics data from XRD and XRF for raw clay and acid-treated clay showed that Bijoypur clay is rich in kaolinite, which contains a significant amount of quartz. However, treatment with HCl reduces 55% of quartz and increases the percentage of kaolinite that made it suitable for adsorbent used. Adsorption results showed that PAA-g-MC composite showed a maximum adsorption of 162.3 mg g−1 of 100 mg L−1 MB dye solution at pH 7.25 after 80 min of adsorption using 0.03 g L−1 of the adsorbent. Langmuir and Freundlich adsorption isotherms were studied and the equilibrium adsorption data were found to be well fitted with the Langmuir adsorption isotherm. The interaction between adsorbent and MB molecules was explained by chemisorption, as suggested by the pseudo-second-order kinetic model. Maximum monolayer adsorption of 168.4 mg g−1 was calculated from the Langmuir adsorption isotherm which is very close to the experimental value of 162.3 mg g−1. [ABSTRACT FROM AUTHOR]

In the present work, treated and untreated novel RA reinforced PET thermoplastic polymer composites were developed. The fibers were chemically modified before fabrication of the composites to have a better fiber-matrix bonding. Thermo-mechanical properties of the composites were studied. An enhancement in mechanical properties were found at the beginning phase with the increase in treated rattan fiber content till optimum fiber loading (i.e 20 wt%) thereafter the properties decline. At 20 wt% fiber loading the mechanical properties obtained were 67.89 MPa of tensile strength, 83.29 MPa of flexural strength, 3.98 GPa of young's modulus, and 24.18 kJ/m2 of impact strength. Different properties of the composites were thoroughly studied and the composites fabricated at 20 wt% of fiber content reveals excellent mechanical and thermal properties and found very much suitable for packaging applications. [ABSTRACT FROM AUTHOR]

The research article focuses on succinct characterization of pineapple leaf fibers before and after different chemical modification techniques so as to ease its usage in developing light weight composite tiles for bathroom floor or wall tiles in building and construction industry. After the surface treatment namely, 7% alkali, 3% acrylic acid, and 1% silane treatment, fibers were analyzed through physical, chemical, morphological, mechanical, and thermal properties using various sophisticated instruments and concluded with the fact that in general, surface treatment helps in strengthen the fiber properties. Fibers with 7% alkali treatment exhibit maximum improvements, 55% increase in tensile strength, 40% increase in crystallinity index, 13% increase in density and 12.6% decrement in diameter. Similar enhancements in fiber quality were witnessed in physical, chemical, and thermogravimetric analysis. After 60% mass degradation of the fiber, fibers with 7% alkali treatment show better thermal stability till around 700°C. [ABSTRACT FROM AUTHOR]

The current study reports the preparation and application of bio-based polymer composite hydrogel with and without a crosslinker for the removal of industrial dye procion blue HERD (PB). Biopolymer chitosan, acrylic acid as a monomer and potassium persulphate (K2S2O8) as an initiator synthesise composite hydrogel. The crosslinked composite hydrogel is synthesised by the microwave irradiation technique using thiourea (CH4N2S) as a crosslinker. Chitosan-based hydrogel synthesised without crosslinker (CH) and with crosslinker thiourea (CH-T) is analysed using techniques, such as Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential thermal analysis (DTG) and derivative thermogravimetric analysis (DTA). The adsorption capacity of CH and CH-T for the removal of PB from an aqueous solution is investigated. The removal efficiency of hydrogel is 90% in a solution of pH 7 for a constant dose of PB (5 mg L−1). The experimental data attained for the adsorption of industrial dye (PB) onto CH and CH-T showed a perfect fit for Freundlich and Langmuir isotherms. The perfect fit of experimental data for PB decolorisation is observed for pseudo-second-order kinetic equation with k values 10.17 × 10−3 mg−1 min−1 and 6.719 × 10−3 mg−1 min−1 with CH and CH-T, respectively. [ABSTRACT FROM AUTHOR]

Development of polymer-based flooding technology to improve oil recovery efficiency, water dispersion copolymerization of acrylamide, cationic monomer methacryloxyethyltrimethyl ammonium chloride (METAC), and anionic monomer acrylic acid (AA) were carried out in aqueous ammonium sulfate solution with polyvinyl pyrrolidone (PVP) as the stabilizer. The copolymers were characterized by 1H-NMR, FT-IR, TG, and SEM to confirm that they were prepared successfully and exhibited excellent salt-resistant property. Moreover, the effect of the aqueous solution of ammonium sulfate (AS) concentration, stabilizer concentration, and initiator concentration on the viscosity and size were systematically investigated. To further improve the thermal endurance properties of copolymer, hydrophobic monomers with different alkyl chain lengths were added to the above system. The acrylamide-based quadripolymer possessed prominent thermal and salt endurance properties by utilizing the advantages of zwitterionic structure and hydrophobic monomer. With the temperature rising, the viscosity retention could reach 70.2% in the water and 63.8% in the saline. This work had expected to provide a new strategy to design polymers with excellent salinity tolerance and thermal-resistance performances. [ABSTRACT FROM AUTHOR]

Ketorolac tromethamine (KT), selected as a model drug, is used in management of moderate to severe acute pain. It has a short half-life (∼5.5 h) and requires frequent dose administration when needed for longer period of time. In our current project, we designed pH responsive hydrogel blends of chondroitin sulfate/pluronic F-127 (CS/Pl) for the controlled release of ketorolac. Hydrogel blends were fabricated using free radical polymerization reaction technique utilizing different ratios of chondroitin sulfate (CS) (polymer) and pluronic F-127 (polymer), acrylic acid (monomer), N,N′-methyl-bisacrylamide (MBA) (cross-linker), initiator ammonium persulfate (APS) and tween-80 (surfactant). The fabricated hydrogel blends were studied and evaluated for pH responsiveness, swelling, water absorbency, in vitro drug release, and morphological characteristics such as SEM, XRD, FTIR, and TGA/DSC. Acute toxicity study was performed on rabbits. Maximum swelling and water absorbency were shown by CS/Pl blends being significantly greater at 7.4 (basic pH) than in 1.2 (acidic pH). In vitro dissolution demonstrated pH responsive controlled KT release following zero order at higher pH (7.4) medium up to 36 h. FTIR studies confirmed the structures of our blends; SEM results showed porous framework; thermal studies revealed higher stability of hydrogels than the individual polymers; and XRD confirmed the nature of our blends. Toxicity study revealed the nontoxic nature of the hydrogel blends. The prepared CS/Pl hydrogels demonstrated stimuli-controlled release with delivery of drug for prolonged period of time and thus can minimize dosing frequency, safe drug delivery, increased patient compliance and easiness. [ABSTRACT FROM AUTHOR]

This article describes our experimental study in which a series of semi-interpenetrating polymer networks (semi-IPNs: S-IPN1, S-IPN2, and S-IPN3), based on acrylic acid (AA), 2-(diethylamino)ethyl methacrylate (DEAEMA), and gum xanthan (GX), were used to remove the dyes methylene blue (MB) and Congo red (CR) from synthetic aqueous solutions. The formation of the semi-IPN hydrogel was confirmed by Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM). In the swelling experiments, the hydrogels showed pH-sensitive behavior and swelled the most and least under acidic and alkaline conditions, respectively. The MB and CR uptakes were studied using the batch technique, and the effects of various conditions were investigated. According to the data, 0.1 g of the S-IPN3 hydrogel with the highest content of GX had maximum removal efficiencies of 79.33% and 80.47% for the dyes MB and CR, respectively. Freundlich isotherm and a pseudo-second order kinetic model best explained the equilibrium and kinetic adsorption of the dyes, respectively. The prepared semi-IPN gels also showed high regeneration performance for the cationic dye MB during four consecutive adsorption-desorption cycles. [ABSTRACT FROM AUTHOR]

Trademark fabric was prepared with the water polyacrylate as a coating agent and a compound of kaolin and CaCO3 as filler to study the fabric's digital inkjet printing performance. Results showed that a 7:5 ratio of kaolin and CaCO3 in the fabric produced uneven pores; the best ink absorption, quick-drying performance and the best printing sharpness and the highest colourfastness to crocking. The coating slurry included 100 g water, 25 g EC-507 modified styrene acrylic emulsion, 75 g compound filler (kaolin and CaCO3 according to mass ratio 7:5), 1.5 g dispersant and 0.375 g crosslinking agent. The optimised coating process was a baking temperature of 150 °C and a baking time of 90 s. The fabric was printed upon using an Epson label printer, producing a printing pattern with good printing sharpness (e.g. lines had no bleeding phenomenon, text and patterns were clear, colours were better and printed two-dimensional codes were scannable). [ABSTRACT FROM AUTHOR]

The low-temperature flow properties of waxy crude oils are considered the determining factor in pipeline transportation. Polymeric additives known as pour point depressants (PPDs) have been developed to control the growth habits of wax crystals to improve the cold flowability of waxy crude oils. In the present article, a copolymer of poly(styrene-co-acrylic acid) was synthesized by batch emulsion polymerization of styrene (St) and acrylic acid (AA). Further, it was esterified with N,N-dimethylethanolamine, then its quaternization had done by dodecyl and hexadecyl bromide. The prepared compounds are characterized by Fourier transform infrared (FTIR), transmission electron microscopy (TEM), and x-ray diffraction (XRD). The efficiencies of the prepared compounds as PPDs and flow improvers were investigated. From the results, it is found that the quaternized ester of the copolymer with hexadecyl bromide (PPD4) exhibited the maximum pour point depression (ΔPP = 18 °C) at1000 ppm. The XRD of asphaltene in the absence and presence of investigated additives were studied. Photomicrography analysis showed a clear effect of the additives on the wax crystal modification. [ABSTRACT FROM AUTHOR]

Recently, considerable researches are conducted to develop promising polymer electrolytes for Li-ion batteries (LIBs). Herein, we prepared poly(lithium acrylate) (PAALi)-based composite polymer electrolytes (CPEs) containing alumina (Al2O3) nanoparticles. The addition of inorganic nanoparticles into the PAALi matrix can not only improve CPE's ionic conductivity ( σ D C ∼ 1.3 × 10 − 2 S / cm at 303 K), but also enhance CPE's mechanical properties due to the nanoparticles acting as cross-linkers between the PAALi chains. We systematically investigated the influences of inorganic nanoparticle types (pure alumina vs. vinyl functionalized alumina) and contents on ionic conduction and mechanical properties of PAALi-based CPEs. [ABSTRACT FROM AUTHOR]

In this work, hydrogels with antimicrobial activity based on the polysaccharide maltodextrin (MD) were prepared by copolymerization with either acrylic acid (AAc) or acrylamide (AAm) to endow chemical functionality to host zinc oxide nanoparticles (ZnO). MD was previously modified with glycidyl methacrylate (GMA) in order to be susceptible to react with these monomers through free radical polymerization. The weight ratio of MD to the respective monomer was tuned in order to know its effect on the formation of a hydrogel. The preparation of these hydrogels was confirmed by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). Swelling studies showed a better capacity to swell water for the polyacrylamide (PAAm)-containing hydrogels than those with polyacrylic acid (PAAc). These results were confirmed by the scanning electron microscopy (SEM) studies where the PAAm-containing hydrogels showed a 3D porous structure morphology with a bigger pore size than the PAAc-containing hydrogels. In addition, the energy-dispersive X-ray spectroscopy (EDX) demonstrated the presence of ZnO in the prepared hydrogels. ZnO-loaded hydrogels showed antimicrobial activity against Escherichia coli and Staphylococcus aureus. These results suggest that these hydrogels could be used in the biomedical area particularly as wound dressings due to their antimicrobial and swelling properties. [ABSTRACT FROM AUTHOR]

In this study, a quad acrylic copolymer composed of four monomers namely acrylic acid, methacrylic acid, butyl acrylate, and methyl methacrylate/cloisite30B(C30B) nanocomposites with different loading of nanoclay (0.5–3.0%) is prepared by the in-situ method for heat resistant adhesive application. Different parameters like solid content, solubility, appearance, acid value, and pH values are measured for each nanoclay filled copolymer. For dispersion and thermal characterization of nanocomposite X-ray diffraction (XRD), High-resolution transmission electron microscopy (HRTEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) are performed. Epoxy resin along with curing agent is added to the acrylic copolymer/C30B nanocomposite to prepare adhesive. The rheological properties for amplitude sweep, frequency sweep, and temperature scan are analyzed. The nanoclay content doesn't affect the shear-thinning component significantly but improves the complex viscosity and elastic behavior of the adhesives. The crossover point shows good dispersion of C30B up to 2.0% in nanocomposite adhesive. Peel strength is found to be increased with an increase in nanofiller content up to 2.0%. A significant improvement in peel strength is observed when exposed to 150 °C for 45 min. Temperature sweep study by rheology and peel strength results at high temperature suggest that these adhesives can be used in high-temperature resistance adhesive application areas like heat seal packaging and fabric lamination. [ABSTRACT FROM AUTHOR]

Fourier Transform Infrared spectra of pure acrylic acid (ARA), dibutyl ether, and their binary solutions at various acid concentrations have been recorded. Density functional theory calculations on ARA monomers and dimers have been carried out. In addition to the cis–cis and trans–trans dimers, cis–trans dimers also exist in liquid acid. The dimer ring formed by carboxyl group has an asymmetry. The experimental asymmetric and symmetric hydroxyl and carbonyl stretching bands have been assigned. Shifts suffered by the absorption bands in binary solutions have been analyzed in view of the formation of heteromolecular hydrogen bonds. [ABSTRACT FROM AUTHOR]

Polymeric carrier for combination therapy of tuberculosis, namely low molecular weight reactive copolymer of acrylic acid with 2-hydroxyethyl methacrylate (AA-co-2-HEMA) with two types of functional groups along the chain has been synthesized. Characteristic features of radical copolymerization were studied and the relationships between the synthesis conditions and the composition, microstructure, and molecular characteristics of the copolymers were established, that is of fundamental interest. The behavior of copolymer macromolecules in aqueous salt solutions was analyzed. A tuberculostatically active derivative of AA-co-2-HEMA containing the amikacin antibiotic and the monofluoroquinolone ciprofloxacin was synthesized. The target multiunit copolymer containing two tuberculostatics with different effect against tuberculosis mycobacterium exhibits high anti-tuberculosis activity. It is characterized by a gradual release of the drugs from the polymer form and is very promising for use in combination therapy of tuberculosis. [ABSTRACT FROM AUTHOR]

Hydrophobic deep eutectic solvents (HDES) are new-generation green solvents that have emerged in recent years. In this study, the efficiency of using HDES as a solvent in separating acrylic acid from its aqueous solution by reactive extraction method was investigated. As a solvent, HDES prepared with a mixture of TOPO and menthol has been used for the recovery of acrylic acid for the first time. Physical properties of HDES mixtures such as density, viscosity, and refractive index were determined. In reactive extraction experiments, TOPO, one of the two basic components in the solvent, was also employed as an extractant. With the help of response surface methodology based on Box-Behnken design, the effect of the parameters of amount of extractant (0.1–0.9 g), Menthol/TOPO molar ratio (2–4), and initial acid concentration (3–9%) on the distribution coefficient was investigated and the model equation was formed. The highest distribution coefficient (D = 7.8) was achieved with the molar ratio of Menthol/TOPO is 2. Upon examining all the results obtained, it was seen that more than 90% of acrylic acid could be extracted from the aqueous phase to the organic phase. [ABSTRACT FROM AUTHOR]

In order to impart good application performance to locust bean gum (LBG) sizes for polyester yarns, methyl acrylate (MA) and acrylic acid (AA) monomers with a variation in feed molar ratio from 1/9 to 4/6 were grafted onto the molecular chains of native LBG to obtain LBG-g-P(MA-co-AA) products with similar grafting ratios through Fenton redox system. Effects of monomer compatibility of MA and AA on sizing performance of the LBG-g-P(MA-co-AA) were studied in terms of apparent viscosity, contact angle of sizing paste on polyester fibers, water-solubility, mechanical properties of sizing film, and adhesion to polyester fibers. It was found that grafting MA and AA with rational compatibility onto the molecular chains of LBG was an effective method to improve the application performance of the vegetable gelatin sizes, such as good toughness of sizing film and high adhesion to polyester fibers. In view of overall performance of the LBG-g-P(AA-co-MA) sizes, the appropriate feed molar ratio of MA/AA should be 3/7. [ABSTRACT FROM AUTHOR]

Sorption of U (VI) onto novel nano material of amine functionalized poly acrylate hydrogel/nano silica was investigated. In the preparation, tri octyl amine, cyclohexane, poly acrylic acid oleic acid mixed with sodium meta silicate and tri ethanol amine to yield nano particles of amine functionalized poly acrylate hydrogel/nano silica. The capability of the newly adsorbent for uranium sorption was estimated using various controlling variables such as medium pH, uranium concentration, equilibrium time, reaction temperature and the interfering ions. The experimental results showed that, rather than chloride or sulfate, the proper loading capacity was achieved at uranyl nitrate species at pH 1 for 30 minutes stirring at 60°C. Where, the loading capacity was 372.52 mg/g. The pseudo-second-order mechanism fit the U (VI) adsorption kinetics on the sorbent material well, the mechanism of intra-particle diffusion governed the sorption process, and the adsorption equilibrium followed the Langmuir model. The thermodynamic parameters calculated ∆S°, ∆G°, and ∆H°, which indicate that U (VI) sorption process is thermodynamically advantageous, spontaneous, and endothermic. It is a promising and efficient nano adsorbent that could be used for upscaling design and application for U (VI) separation from acidified monazite leach liquor. [ABSTRACT FROM AUTHOR]

A series of fluorinated polyacrylate emulsion pressure-sensitive adhesives (PSA) with various lengths fluorinated side chains were synthesized by using n-butyl acrylate (nBA), acrylic acid (AA), 2-hydroxyethyl acrylate (HEA) together with three kinds of fluorine monomers trifluoroethyl methacrylate (TFEMA), hexafluorobutyl methacrylate (HFBMA) and dodecafluoroheptyl methacrylate (DFHMA). The influences of fluorocarbon chains' length on the particle size of the latex, as well as on thermostability (DSC, TG) and surface properties (XPS, CA, AFM) of the PSA films were investigated. The results showed that Tg and thermal stability of the PSA were both increased with the introduction of F-monomers with various lengths of fluorinated side chains, and the shorter the side chain, the more the Tg and thermal stability increased. The XPS results indicated that the surface atom percentage of F element of film increased with the escalation of the length of fluorocarbon lateral chain, which results in the water contact angle and surface roughness increment of the PSA films. Finally, effects of fluorocarbon chains' length on the adhesive properties (i.e. loop tack, peel strength and shear strength) of the fluorinated latex PSA were also evaluated. [ABSTRACT FROM AUTHOR]

Based on (E)-2-cyano-3-(5-(2-(4-(dimethylamino)phenyl)ethynyl)thiophene-2-yl)acrylic acid (CSD-01) dye, newly designed isolated organic (CSDS1-CBDS7) molecules were investigated for dye-sensitised solar cells (DSSCs) application using the density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. The electronic and optimised geometry of the CSDS1–CSDS7 derivatives were contained in the electron-donor (D), π-linker (π) and electron–acceptor (A) groups to form a D–π–A structure. Different hybrid functionals were used to get a maximum value of optical absorption UV-Vis peak in CSD-01 dye. Accordingly, a ωB97XD was sensibly found by calculating the UV-Vis in CSD-01. Further, UV-Vis spectra were used to design newly efficient sensitisers by the TD-DFT-ωB97XD-6-31G(d) theory. The CSDS1–CSDS7 dyes were implemented on the driving force of the electron injection ( Δ G inject ), dye regeneration ( Δ G reg ), dipole moment ( μ normal ), light-harvesting efficiency, theoretical open-circuit photovoltage ( e V OC ), excited-state lifetime (τ), the density of state, the exciton binding energy ( E b ) and molecular electrostatic potential. The highest occupied molecular orbitals below the redox electrolyte and lowest unoccupied molecular orbitals above the conduction band edge of the TiO2 surface were successfully identified. Finally, the newly CSDS5 and CSDS6 structured sensitisers were offered theoretical tools for highly efficient organic photosensitisers for further research. [ABSTRACT FROM AUTHOR]

During the synthesis of phosphabetaines and phosphonium salts that are good catalysts and antimicrobial agents, the formation of triphenylphosphine oxide was observed. A new synthesis method for phosphonium salts based on tertiary phosphines and substituted acrylic acids was suggested. In vitro antibacterial and antimycotic activity was determined in comparison to standard agents. [ABSTRACT FROM AUTHOR]

Three-network hydrogels have a wide range of applications due to their different network structures and diverse cross-linking methods. In this work, a triple-network hydrogel strategy based on double network coordination and cross-linking is proposed, including gelatin (Gelatin) network, polyacrylamide acrylic acid (PAMAAc) network, and sodium alginate (SA) network. SA and AAc molecular chains contain a large amount of -COO-, which can coordinate with metal ions and generate a large number of dynamic coordination bonds. The hydrogel forms the PAMAAc network through free radical polymerization, and at the same time the interpenetrating cross-linked Gelatin network and SA network are formed through hydrogen bonding. In addition, the addition of metal ions realizes the coordination cross-linking of the double network in the hydrogel. Moreover, the prepared composite hydrogels exhibit good mechanical properties and self-recovery properties. It should be noted that the concentration of different metal ions and the time of coordination and crosslinking will affect the mechanical properties of the hydrogel. The current work provides an idea for preparing a three-network hydrogel with high compressive strength and fast self-recovery. [ABSTRACT FROM AUTHOR]