Gold nanoparticles–loaded cinnamoyl pluronic F-127/cinnamoyl alginate microparticles prepared by a spray-drying method

A gold nanoparticle (GNP)–loaded microparticle was prepared by spray drying the mixture solution of GNP, cinnamoyl pluronic F127, and cinnamoyl alginate, and by dimerizing the cinnamoyl groups under the irradiation of UV light. The cinnamic acid content in the cinnamoyl polymers was determined by ¹H NMR spectroscopy and colorimetric method. The GNP content in the surface of microparticle was 6.45% (w/w), determined by energy-dispersive X-ray spectroscopy. The cumulative release amount for 12?h at 45°C was markedly higher than that observed at lower temperatures. Near-infrared irradiation significantly promoted the release from the GNP-loaded microparticle because of heat generation from GNP.     

Preparation of double layered shell microparticles containing an acid dye by a melt dispersion–coacervation technique

Two types of microparticles with a double layered shell containing an acid dye were prepared by using a melt dispersion–coacervation process. The surface morphology and the composition of the microcapsules were investigated using scanning electron microscope (SEM), and Fourier-transform infrared spectroscope (FTIR) respectively. The results showed that the loading content and morphologies strongly depend on the composition, the protective colloid, as well as on the outer polymeric shell and the way the solvent solubilizes it. The thermo-physical properties strongly depend on the nature of the core content and the synthesis conditions. Factors affecting the release performance of the microcapsules were investigated and the results are presented in this paper.     

Synthesis and characterization of boron doped bismuth–calcium–cobalt oxide nanoceramic powders via polymeric precursor technique

In this study, boron doped calcium stabilized bismuth cobalt oxide nanocrystalline ceramic powders were successfully prepared from aqueous boric acid containing calcium–bismuth–cobalt acetate/poly(vinyl alcohol) hybrid precursor polymer solutions. Then, obtained ceramic powders were characterized via FT-IR, XRD, and SEM techniques. According to X-ray results, fcc and bcc phases coexist in the samples of the nanocrystalline ceramic powders. fcc peaks became sharper and bcc peak decreased with increasing boron content. Structural parameters for face centered cubic structure were calculated using the Scherrer equation. Moreover, dislocation densities and microstrain values were calculated for the nanocrystalline powder samples.     

Investigation of solvent–solute interactions and film properties of perfluorinated sulfonic acid (PFSA) ionomers

In this work, solvent composition effects on the average particle size and polydispersity of the commercial perfluorinated sulfonic acid (PFSA) membrane, i.e., Flemion^®, in different solution mixtures were studied. Dynamic light scattering experiments were employed to determine the aggregate sizes of dispersed PFSA polymers in different water/alcohol solutions. The particle size distribution of the solute was analyzed and discussed for different solvent–solute systems. As the solvent gets more compatible with the Flemion^®, the particle size reduced. Increasing the water content in propanol/water mixture increased the average particle size of the solute. Comparing three solution mixtures shows that the mean particle size increased as the solvent was changed in the order of ethanol, methanol and propanol. Differential scanning calorimetry (DSC) tests were conducted on the films obtained by recasting from different solution compositions. The results of DSC tests were used to investigate the water absorption and other thermal behavior. Structural properties such as equivalent weight of the polymer, free volume and the degree of aggregation of ionic groups or size of the clusters can influence the water uptake. DSC test results showed four different endothermic peaks which can be attributed to removal of surface and intergrain structural absorbed water, melting of crystalline segments and thermal degradation of the polymer, respectively.     

Development and characterization of a lignin–phenol–formaldehyde wood adhesive using coffee bean shell

In the present study, the possibility of development of a wood adhesive using coffee bean shell lignin (Cbsl) has been explored. Cbsl-modified phenolic adhesive has been prepared by replacing phenol with lignin at different weight percents. The optimization of weight percent lignin incorporation was carried out with respect to mechanical properties. It was found that up to 50 wt% of phenol could be replaced by Cbsl to give lignin–phenol–formaldehyde adhesive (LPF) with improved bond strength in comparison to control phenol–formaldehyde (CPF). Optimized LPF and CPF adhesives were characterized by IR, DSC and TGA. The IR spectrum of LPF showed structural similarity to CPF. Thermal stability of LPF adhesive was found to be lower as compared to that of CPF. DSC studies revealed a higher rate of curing in the LPF adhesive.     

Comparison of poly(ethylene-co-acrylic acid) loaded Zn2+–montmorillonite nanocomposites and poly(ethylene-co-acrylic acid) zinc salt

Novel nanocomposite films based on poly(ethylene-co-acrylic acid) (PEAA) and zinc montmorillonite (Zn²⁺–MMT) were fabricated using a solution casting method with water as the solvent. Transmission electron microscopy indicated that Zn²⁺–MMT was distributed finely in the PEAA matrix. X-ray diffraction indicated that an ion exchange process occurs between Zn²⁺–MMT and PEAA. The nanocomposites filled with a low Zn²⁺–MMT loading increased the tensile strength and elongation at break. The significant improvements in these mechanical properties were attributed to the fine dispersion of Zn²⁺–MMT in the polymer and the covalent interaction between the polymer chains and Zn²⁺ cations. Thermogravimetric analysis and differential thermal calorimetry confirmed that PEAA formed a network through the presence of Zn²⁺ cations. A poly(ethylene-co-acrylic acid) zinc salt (PEAAZn) film by hot pressing was introduced for comparison. Zn²⁺–MMT improved the mechanical properties of the PEAA significantly compared to that of PEAAZn.     

Synthesis and characterization of thermosensitive core–shell polymeric nanoparticles

Thermosensitive core–shell nanoparticles were synthesized by semicontinuous heterophase polymerization of styrene, followed by a seeded polymerization for forming a shell of poly(N-isopropyl acrylamide) (PNIPAM). Nanoparticles characterization by scanning transmission electronic microscopy showed core–shell morphology with average particle diameters around 40 nm. An inverse dependence of the particle size with temperature in the range 20–55 °C was identified by quasielastic light scattering measurements. As was expected for core–shell particles with PNIPAM as the shell, a volume phase transition near 32 °C was detected. In spite of thermosensitive properties of core–shell nanoparticles synthesized here, the volume percentage loss values were not so high, probably due to their relatively low content of PNIPAM.     

Influence of solvent,Lewis acid–base complex,and nanoparticles on the morphology and gas separation properties of polysulfone membranes

A series of polysulfone (PSF) membranes were prepared using different solvents: dimethylformamide (DMF), tetrahydrofuran, dimethylacetamide, and n-methyl-2-pyrrolidone (NMP). The PSF membrane prepared by NMP showed the highest gas permeability. The influence of propionic acid as a Lewis acid on gas separation properties of the PSF was explored. The PSF membrane prepared by the casting solution containing 25 wt% PSF, 35 wt% propionic acid, and 40 wt% NMP showed a superior gas separation performance. The gas permeation measurements indicated that incorporating 30 wt% γ-alumina nanoparticles into the PSF matrix resulted in about the respective 43% and 41% increase in CO₂ and O₂ permeability together with a rise in CO₂/CH₄ and O₂/N₂ selectivities (13% and 7%, respectively). Furthermore, by rearranged modified Maxwell model, the role and nature of the interfacial layer in the PSF-based mixed matrix membranes were mathematically analyzed considering a reduced permeability factor.     

Rapid construction of hierarchically porous metal–organic frameworks by a spray-drying strategy for enhanced tannic acid adsorption

Metal–organic frameworks (MOFs) have attracted much attention owing to their tailored pore environment and surface functionality. However, most of the currently reported MOFs are confined to small pore sizes (<5 nm), limiting their practical applications. Here, a facile and versatile strategy for rapid construction of hierarchically porous MOFs (HP-MOFs) by spray-drying is reported, in which presynthesized nanosized MOFs (N-MOFs) can be assembled to form MOF microspheres with meso/macropores resulting from the interspace among closely arranged N-MOFs. This strategy enables the construction of multicomponent HP-MOFs with various functions. As a proof of concept, we show that the adsorption for tannic acid (TA) can be significantly enhanced using HP-MIL-101(Cr). Particularly, HP-MIL-101-30 (30 represents the primary nanoparticle size) exhibits a record-high adsorption capacity (1175 mg g⁻¹), and the adsorption rate of HP-MIL-101-30 is increased by 50% compared to that of N-MIL-101-30. These findings have important implications for the rapid construction of HP-MOFs, which is beneficial for the adsorption of large molecules.     

Preparation and controlled release of degradable polymeric ketoprofen–saccharide conjugates

A facile and efficient enzymatic and polymerization process was used to prepare polymeric prodrugs of ketoprofen with saccharide side chains. The chains included branches that included glucose, mannose, galactose, and lactose, and these were synthesized through free radical reaction. The prodrugs were characterized by FT-IR, NMR, and GPC and drug-loading capacity was influenced by varying the ratios of initiator and monomers (range 32.13 and 68.56% w/w). In vitro release characteristics of the polymeric drugs were systematically evaluated over the pH range 1.2–8.0 and the release profiles indicated that the hydrolytic nature of polymers were strongly depended on the variation in saccharide content, carbon chain length, and pH. The outcomes from this study demonstrate the importance of carbohydrate structures and how these are linked to drug release.     

Turbidimetric and intrinsic viscosity study of EVA copolymer–solvent systems

Both Hansen solubility parameter and Flory–Huggins interaction parameter of two EVA [Poly(ethylene-co-vinyl acetate)] copolymers with different vinyl acetate content have been obtained by means of intrinsic viscosity measurements. To calculate this last parameter it was also necessary to determine the theta solvent at different temperatures of the two EVA copolymers with turbidimetric measurements. The results indicate that the vinyl acetate content is a variable which influences the composition of the theta solvent and Flory–Huggins parameter (the higher the vinyl acetate content, the lower the Flory–Huggins parameter), although its influence over the Hansen solubility parameter is almost negligible.     

Fabrication and in vitro characterization of fenofibric acid-loaded hyaluronic acid–polyethylene glycol polymeric composites with enhanced drug solubility and dissolution rate

The target of the present work was to formulate and characterize a fenofibric acid-loaded hyaluronic acid–polyethylene glycol (HA-PEG) polymeric composite to improve solubility and dissolution of the drug in the aqueous media. Several fenofibric acid-loaded HA-PEG polymeric composites were fabricated with varying quantities of HA and PEG 6000 using the solvent-evaporation method. The impact of relative quantities of HA and PEG was examined on solubility and dissolution of the drug. The thermal and structural physiognomies were investigated using X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Spectroscopic study was accomplished by Fourier transform infrared spectroscopy (FTIR). Shape and surface features of the solid particles were observed using scanning electron microscopy (SEM). All the formulations demonstrated greater solubility and dissolution than did plain fenofibric acid powder. Both the HA and PEG positively affected solubility and dissolution of the drug in the aqueous media. A fenofibric acid-loaded HA-PEG polymeric composite, consisting of fenofibric acid/HA/PEG at the weight ratio of 0.5/6.0/0.75, respectively, provided the highest solubility (0.45?±?0.05?mg/mL) and dissolution (～90% in 15?min) in this study. Moreover, the loaded drug was in the amorphous state, and had no covalent linkages with polymeric matrices. Thus, this HA-PEG polymeric composite might be a suitable drug delivery system for oral administration of fenofibric acid.     

Electrometallurgical recovery of nickel and vanadium from spent desulphurization catalysts using an acidic leaching–electrolysis technique

Spent desulphurization catalysts are considered a major secondary source of valuable metals. The contents of nickel and vanadium present in these catalysts, accompanied by environmental rules, have attracted scientists to explore diverse options for their effective processing. The electrometallurgy recovery of Ni and V from the spent desulphurization Ni-Mo-V/Al₂O₃ catalyst is described in this study. Using flat plate graphite electrodes, the electrochemical deposition of Ni and V from spent catalyst in an acid solution (HNO₃/H₂SO₄) was investigated. By the central composite design of the response surface methodology, the effect of the operating factors was examined and optimized. At the ideal conditions of reaction temperatures of 84.0 and 42.0°C, electrolysis times of 5.6 and 4.4 h, liquid/solid ratios of 22.7 and 15.4 ml/g, and current densities of 229.0 and 255.6 A/m², respectively, the recovery efficiencies of Ni and V were 81.96% and 93.07%. The statistical analysis revealed that the expected data (R² = 0.9984 and R² = 0.9883) were in good agreement with the observed data (R² = 0.9984), with an average variation from experimental data of 0.78% and 0.65% for the optimum conditions of Ni and V recovery, respectively. It shows that the Ni and V nanoparticles deposited have a spherical form with purities of 84.39% and 90.76%, respectively. Because of its great efficiency and purity, the current study can provide a dependable procedure for extracting Ni and V from solid waste.     

Hydroformylation of 1-octene using rhodium–phosphite catalyst in a thermomorphic solvent system

The use of a liquid–liquid biphasic thermomorphic or temperature-dependent multicomponent solvent (TMS) system, in which the catalyst accumulates in one of the liquid phases and the product goes preferably to the other liquid phase, can be an enabling strategy of commercial hydroformylation processes with high selectivity, efficiency and ease of product separation and catalyst recovery. This paper describes the synthesis of n-nonanal, a commercially important fine chemical, by the hydroformylation reaction of 1-octene using a homogeneous catalyst consisting of HRh(PPh₃)₃(CO) and P(OPh)₃ in a TMS-system consisting of propylene carbonate (PC), dodecane and 1,4-dioxane. At a reaction temperature of 363 K, syngas pressure of 1.5 MPa and 0.68 mM concentration of the catalyst, HRh(CO)(PPh₃)₃, the conversion of 1-octene and the yield of total aldehyde were 97% and 95%, respectively. With a reaction time of 2 h and a selectivity of 89.3%, this catalytic system can be considered as highly reactive and selective compared to conventional ones. The resulting total turnover number was 600, while the turnover frequency was 400 h^?1. The effects of increasing the concentration of 1-octene, catalyst loading, partial pressure of CO and H₂ and temperature on the rate of reaction have been studied at 353, 363 and 373 K. The rate was found to be first order with respect to concentrations of the catalyst and 1-octene, and the partial pressure of H₂. The dependence of the reaction rate on the partial pressure of CO showed typical substrate inhibited kinetics. The kinetic behavior differs significantly from the kinetics of conventional systems employing HRh(CO)(PPh₃)₃ in organic solvents. Most notable are the lack of olefin inhibition and the absence of a critical catalyst concentration. A mechanistic rate equation has been proposed and the kinetic parameters evaluated with an average error of 5.5%. The activation energy was found to be 69.8 kJ/mol.     

Recycling of polymers from plastic packaging materials using the dissolution–reprecipitation technique

In this work, results are presented on the application of the dissolution/reprecipitation technique in the recycling of polymers from waste plastic packaging materials used in food, pharmaceuticals and detergents. Initially, the type of polymer in each packaging was identified using FT-IR. Furthermore, experimental conditions of the recycling process (including type of solvent/non-solvent, initial polymer concentration and dissolution temperature) were optimized using model polymers. The dissolution/reprecipitation technique was applied in the recycling of a number of plastic materials based on polyethylene (LDPE and HDPE), polypropylene, polystyrene, poly(ethylene terephthalate) and poly(vinyl chloride). The recovery of the polymer was measured and possible structural changes during the recycling procedure were assessed by FT-IR spectroscopy. Potential recycling-based degradation of the polymer was further investigated by measuring the thermal properties (melting point, crystallinity and glass transition temperature), of the polymer before and after recycling, using DSC, their molecular properties (average molecular weight) using viscosimetry, as well as their mechanical tensile properties. High recoveries were recorded in most samples with the properties of the recycled grades not substantially different from the original materials. However, a slight degradation was observed in a few samples. It seems that this method could be beneficial in waste packaging recycling program.     

Fabrication and characterization of multiwalled carbon nanotube–loaded interconnected porous nanocomposite scaffolds

Novel nanocomposite porous scaffolds based on poly(?-caprolactone) (PCL) and multiwalled carbon nanotubes (MWCNTs) were manufactured by a compression-molding/polymer-leaching approach utilizing cryomilling for homogeneous dispersion of nanotubes and blending of polymers. Addition of MWCNTs to PCL and PCL/polyglycolide (PGA) blends resulted in significant changes to scaffold morphology compared to control samples despite persistent interconnected porosity. Several structures exhibiting rough and nanotextured surfaces were observed. Mean pore sizes were in the range of ～3–5?µm. The nanocomposites presented good mechanical and water uptake properties. The results of this research provide significant insight into a strategy for producing nanocomposite scaffolds with interconnected porosity.     

Reduction of solvent content in toluene–neoprene adhesives and in acetone–polyurethane adhesives

The desorption of toluene in a polychloroprene (neoprene)-toluene adhesive and in a commercial neoprene adhesive was studied in air at three different temperatures by monitoring the weight loss vs time. Similarly, the desorption of acetone in a polyurethane adhesive and in a commercial adhesive was also considered. The experimental weight variations are correlated with the solution of the second Fick law at non-steady state. As the volume is highly reduced when the solvent is evaporated from the solvent-polymer mixture, the correlations obtained are discussed on the basis of the variation of the diffusivity with the solvent concentration, assuming that the product of the diffusivity and the polymer volume fraction to the power 2 is approximately constant. Apparent activation energies were obtained for the four adhesives used.     

Synthesis and characterization of potassium humate–acrylic acid–acrylamide hydrogel

A novel potassium humate–acrylic acid–acrylamide (KHA–AA–AM) superabsorbent polymer was prepared from the reaction among leonardite potassium humate, acrylic acid and acrylamide by free radical initiating process using ammonium persulfate as the initiator and N, N′-methylene bisacrylamide as the crosslinker. Various effects of synthesis conditions on superabsorbent polymer were studied and the optimal reaction condition was obtained with crosslinker concentration 0.44–0.74 wt%, initiator concentration 1.12–2.22 wt%, n(KOH)/n(AA) 0.51–0.70, monomer concentration 10.95–12.59 wt%, graft reaction temperature 83 ± 1°C, monomer mole ratio of acrylic acid to acrylamide 1.42–2.30, and potassium humate content 17.54 wt%. Under the optimal conditions, the solution absorbency of KHA–AA–AM superabsorbent polymer to deionized water, tap water, 0.5% carbamide solution and 0.9% NaCl solution were 733–756, 161–284, 786–825, and 76–83 g/g, respectively.     

Correlation between quantity of defect and supersaturation in RDX crystallization using γ-butyrolactone and water as solvent

The crystallization of RDX (cyclotrimethylenetrinitramine) was carried out using cooling crystallization. Effect of cooling rate and antisolvent to solvent ratio on the inclusion was studied. Qualitative observation of internal crystal defects was performed by optical microscopy with matching refractive index. The quantitative amount of inclusions was determined by measuring concentration of solid. Effect of the cooling rate and the antisolvent to solvent ratio on supersaturation was investigated. The supersaturation affected significantly the inclusion of mother liquor inside the crystals. The higher supersaturation induced the more agglomeration, that caused the formation of the more inclusions inside RDX crystals. From morphological study, defect is formed in course of transformation from plate-like to polygon shape. An empirical correlation of the inclusion fraction of RDX with the relative supersaturation was obtained.     

Synthesis and fluorescence properties of a waterborne polyurethane–acrylic hybrid polymeric dye

A waterborne polyurethane–acrylic hybrid polymeric dye was prepared depending on soap-free emulsion polymerization method. The resulting polymeric dye composed of methyl methacrylate (MMA) monomer which was polymerized into polymethyl methacrylate (PMMA) as cores and waterborne polyurethane-based dye was synthesized by anchoring dye monomers (6-amino-2-cyclohexyl-benz[de]isoquinone-1,3-dione) to polyurethane chains as shells. The average particle sizes of the hybrid polymeric dye emulsions were found to be increased with the increase in MMA contents for MMA monomers. Compared with dye monomers, the absorption intensities and fluorescence intensities of the hybrid polymeric dye were enhanced with the increase of particle sizes. This study revealed that enhanced fluorescence intensity of the hybrid polymeric dye was mainly attributed to the hindered formation of exciplexes among dye monomers and an augmented light absorption area. It was found that the fluorescence intensity of the hybrid polymeric dye was increased with increasing temperature and the trend first increased and then decreased with increase in concentration. Furthermore, the fluorescence of the hybrid polymeric dye emulsions was found to be very stable and not sensitive to the fluorescence quencher.