Solid Resin Research Articles

Reduction of photo bleaching and long term archiving of chemically cleared GFP-expressing mouse brains.

Tissue clearing allows microscopy of large specimens as whole mouse brains or embryos. However, lipophilic tissue clearing agents as dibenzyl ether limit storage time of GFP-expressing samples to several days and do not prevent them from photobleaching during microscopy. To preserve GFP fluorescence, we developed a transparent solid resin formulation, which maintains the specimens' transparency and provides a constant signal to noise ratio even after hours of continuous laser irradiation. If required, high-power illumination or long exposure times can be applied with virtually no loss in signal quality and samples can be archived for years.

Development of Synthetic Ketonic Resin

In the present work, the self-polymerization reaction of cyclohexanone was studied to develop a synthetic resin. Synthetic resins are extensively used in paint industry to improve the adhesiveness of paints. Polymerization reactions were carried out in a high-pressure reactor. The results suggest that the self-polymerization of cyclohexanone mainly depends on alkali concentration, reaction temperature, and reaction time. As the ketone-to-alkali ratio decreases, the degree of polymerization increases, which leads to an increase in the hydroxyl value and softening point and a remarkable decrease in solubility. A good-quality solid resin could be obtained with a ketone-to-alkali ratio less than 5 in the temperature range between 130°C and 160°C and within the time duration of 12–22 h. These data may be useful to develop the desired quality of resin in the field of paint application.

Uncertainty contributions to the measurement of dissolved Co, Fe, Pb and V in seawater using flow injection with solid phase preconcentration and detection by collision/reaction cell—quadrupole ICP–MS

A flow injection manifold incorporating a solid phase chelating resin (Toyopearl AF-Chelate-650) is reported for the preconcentration of dissolved metals from seawater, with a focus on investigating the effect of the loading pH, wash solution composition and wash time. Cobalt, iron, lead and vanadium have been used as target analytes with contrasting oceanographic behaviour. Quadrupole ICP–MS has been used for detection to make the approach accessible to most laboratories and a collision/reaction cell has been incorporated to minimise polyatomic interferences. Results for the seawater CRM NASS-6 and two GEOTRACES reference materials were in good agreement with the certified/consensus values, demonstrating the suitability of the approach for the determination of trace metals in seawater. The experimental design used allowed a thorough investigation of the uncertainty contribution from each method parameter to the overall expanded uncertainty of the measurement. The results showed that the parameters making the largest contributions were the precision of the peak area measurement and the uncertainty associated with the slope of the calibration curve. Therefore, these are the critical parameters that should be targeted in order to reduce the overall measurement uncertainty. For iron, the wash blank also gave a measureable contribution.

Simultaneous analysis of apolar phytohormones and 1-aminocyclopropan-1-carboxylic acid by high performance liquid chromatography/electrospray negative ion tandem mass spectrometry via 9-fluorenylmethoxycarbonyl chloride derivatization

A strategy to detect and quantify the polar ethylene precursor 1-aminocyclopropan-1-carboxylic acid (ACC) along with the more apolar phytohormones abscisic acid (ABA), indole-3-acetic acid (IAA), jasmonic acid (JA), jasmonic acid-isoleucine conjugate (JA-Ile), 12-oxo-phytodienoic acid (OPDA), trans-zeatin, and trans-zeatin 9-riboside using a single extraction is presented. Solid phase resins commonly employed for extraction of phytohormones do not allow the recovery of ACC. We circumvent this problem by attaching an apolar group to ACC via derivatization with the amino group specific reagent 9-fluorenylmethoxycarbonyl chloride (Fmoc-Cl). Derivatization in the methanolic crude extract does not modify other phytohormones. The derivatized ACC could be purified and detected together with the more apolar phytohormones using common solid phase extraction resins and reverse phase HPLC/electrospray negative ion tandem mass spectrometry. The limit of detection was in the low nanomolar range for all phytohormones, a sensitivity sufficient to accurately determine the phytohormone levels from less than 50mg (fresh weight) of Arabidopsis thaliana and Nicotiana benthamiana tissues. Comparison with previously published phytohormone levels and the reported changes in phytohormone levels after stress treatments confirmed the accuracy of the method.

Comparison of thermal curing behavior of liquid and solid urea–formaldehyde resins with different formaldehyde/urea mole ratios

This study was undertaken to compare thermal cure kinetics of urea–formaldehyde (UF) resins, in both liquid and solid forms as a function of formaldehyde/urea (F/U) mole ratio, using multi-heating rate methods of differential scanning calorimetry. The requirement of peak temperature (Tp), heat of reaction (ΔH) and activation energy (E) for the cure of four F/U mole ratio UF resins (1.6, 1.4, 1.2 and 1.0) was investigated. Both types of UF resins showed a single Tp, which ranged from 75 to 118 °C for liquid resins, and from 240 to 275 °C for solid resins. As the F/U mole ratio decreased, Tp values increased for both liquid and solid resins. ΔH values of solid resins were much greater than those of liquid resins, indicating a greater energy requirement for the cure of solid resins. The ΔH value of liquid UF resins increased with decreasing in F/U mole ratio whereas it was opposite for solid resins, with much variation. The activation energy (Ea) values calculated by Kissinger method were greater for solid UF resins than for liquid resins. The activation energy (Eα) values calculated by isoconversional method which showed that UF resins in liquid or solid state at F/U mole ratio of 1.6 followed a multi-step reaction in their cure kinetics. These results demonstrated that thermal curing behavior of solid UF resin differed greatly from that of liquid resins, because of a greater branched network structure in the former.

Nano Cavity Induced Isotope Separation of Zinc: Density Functional Theoretical Modeling

Density functional theoretical calculation was performed to understand the isotopic fraction of zinc in the nano cavity of different crown ethers and crown ethers anchored on solid resin matrix. The structure, energetic, thermodynamics, and vibration IR spectra were also evaluated. The gas phase binding energy of Zn2+ with crown ether of varied cavity can be correlated with NPA charge transfer but no such correlation is obtained with the fraction of electron transfer, ΔN. The reduced partition function ratio (RPFR) of complexes of Zn2+ ion with different solvents, crown ethers, and grafted crown ethers was also computed to predict the isotope separation factor of the Zn2+ ion. The present study reveals that with increasing cavity size of the crown ether the RPFR was found to be decreased leading to a high value of isotope separation factor as observed in the experiments. An attempt was made to correlate the calculated RPFR and separation factor with binding energy of different zinc-crown ether systems. Fu...

Research on Performance of Foundry Sand under the Effect of Chemical Binder

This paper makes an experiental research on the performance of foundry sand under the effect of chemical binder. It discoveries the raw sand with different origin will have different properties even though they have the same particle size. The properties of their molding sand are also obviously different. For the raw sand that in the same particle size with similar acid demand value and four-screen distribution, the better grain shape will earn them a higher molding sand strength even though they have higher clay content. Under the effect of liquid binder, compared to the molding sand mixed from the sand of three-screen distribution, the molding sand mixed from those of four-screen distribution sand with other properties similar will have a higher tensile strength While under the effect of solid phenolic resin adhesive, the three-screen sand with good grain shape will have a high sand strength.

Avaliação do potencial de uso da madeira de Acrocarpus fraxinifolius, Grevilea robusta, Melia azedarach e Toona ciliata para produção de painéis OSB

Este trabalho teve como objetivo avaliar o potencial de uso da madeira de Acrocarpus fraxinifolius, Grevilea robusta, Melia azedarach e Toona ciliata, e mistura destas espécies, para produção de painéis OSB. Os painéis foram produzidos em laboratório com densidade nominal de 0,75 g/cm³, utilizando resina fenol-formaldeído em quantidade de 6% de sólido resinoso e 1% de emulsão de parafina. Foram avaliadas as propriedades de absorção de água e inchamento em espessura 2 e 24 horas, tração perpendicular, módulo de elasticidade e de ruptura paralelo e perpendicular, de acordo com as normas EN 317, 318 e 310/2003, respectivamente. Os painéis OSB produzidos com as 4 espécies e mistura destas, apresentaram valores médios de propriedades físicas e mecânicas acima do requisito mínimo estabelecido pela norma CSA 437/1993. Os resultados das propriedades físicas e mecânicas obtidas indicam a viabilidade de uso das madeiras de Acrocarpus fraxinifolius, Grevilea robusta, Melia azedarach e Toona ciliata, e mistura destas espécies, para produção de painéis OSB.

Sulfonic acid functionalized deoxycellulose catalysts for glycerol acetylation to fuel additives

Various forms of sulfonic acid (SO3H) functionalized cellulose-based heterogeneous catalysts were prepared, and their properties on glycerol acetylation reactions to mono-, di-, and triacetin products were investigated. Superior catalytic activity and stability for the reactions was observed on SO3H-NDOC catalyst that is obtained by (i) crosslinking of the cellulose units with epichlorohydrin into a three-dimensionally-networked deoxycellulose-matrix and (ii) sulfonic acid functionalization on the crosslinked deoxycellulose support via CS atomic linkages (CSO3H). It was found that sulfonic acid functionalization via an ether type OS atomic linkage (COSO3H) or the direct utilization of the pristine cellulose support without a fortification by crosslinking led to significant deactivation of the catalysts by substantial acidity loss. The intrinsic glycerol conversion turnover rate on SO3H-NDOC was comparable to that of commercial Amberlyst-15 solid resin, demonstrating the effectiveness of this renewable cellulose-derived heterogeneous catalyst for glycerol acetylation to fuel additives.

Recent Trends on Achieving Taste Masking of Bitter Drug

Taste is most important organoleptic aspects about the acceptance of oral drugs. Bitter and unpalatable taste is a major problem of certain drugs in formulations. In market, there are numbers of pharmaceutical preparations available in which actives are bitter in taste. The improved palatability in these products has prompted the development of numerous formulations, which improved performance and acceptability. The bitterness of preparation also leads to patient incompliance. So masking of bitterness becomes essential and done by masking the bitter taste of drugs by either decreasing its oral solubility on ingestion or decreasing the amount of drug particles exposed to taste buds thereby reducing the perception of bitter taste. Methods commonly used for taste masking involves various physical and chemical method that prevent the interaction of taste bud with drugs and are based on coatings, solid dispersion system and ion exchange resin, entrapment method etc. Taste masking of bitter drugs become necessity in case of oral administration and selection of technology depends upon the bitterness of drugs and their compatibility with taste masking agents that does not affect the bioavailability of drug.

Portable Solid Phase Extraction of Copper, Cadmium and Lead Using Analig ME-02 Chelating Resin and Their Determination by Atomic Absorption Spectrometry

The adsorption of metallic elements on the solid phase chelating resins is probably the most effective separation and preconcentration methods. In this work, portable Solid phase extraction (SPE) was constructed using a commercially available plastic syringe containing certain amount of the Analiq ME-02 chelating resin. The ability of this portable SPE was evaluated through adsorption-desorption process of copper, lead, and cadmium prior their determination by atomic absorption spectrometry (AAS). Some parameters affecting the adsorption-desorption of these heavy metal ions on the Analiq ME-02, which include effect of pH and concentration of eluent ((HNO3), were investigated in detail. It was found that quantitative adsorptions (> 90%) of copper, lead, and cadmium are obtained at all pHs (48) examined, whereas 1 M HNO3 was found to be effective for the desorption of these metals with the recoveries in the range of 93 -114%. Such results indicated that Analig ME-02 has excellent chelating ability (pH-independent) for the adsorption of copper, lead, and cadmium, while portable SPE system provides easiness and effectiveness for collection/preconcentation of metallic elements.

Solid-phase extraction employing 5-methyl-4-(2-thiazolylazo)resorcinol entrapped in sol-gel glass as a sorbent resin to remove Zinc ions

Aim: The ligand 5-methyl-4-(2-thiazolylazo)resorcinol (5-Me-TAR) was encapsulated in an optically transparent, inert and porous sol-gel glass to produce a solid resin. The synthesized composite (resin) was used as a solid phase extractant to remove (as a filter) zinc ions from water samples. Materials and Methods: A solution of the ligand in ethanol was mixed with selected alkoxysilanes in the presence of water to produce a homogeneous mixture. By hydrolysis and condensation of the alkoxysilanes, solid glass forms around the dopant. The ligand molecule is entrapped inside the glass pores, while small Zn(II) metal ions can diffuse into the pores where they are complexed by the ligand and retained inside the pores. Absorption and fluorescence spectroscopy were used to characterize 5-Me-TAR ligand and 5-Me-TAR-Zn complex both in solution and sol-gel glass. The sol-gel glass precursors were carefully selected to produce a glass composite material doped with the ligand with no leaching, especially when the glass is soaked in the solution. Results: Complexation using the batch method was employed, in which a known weight of the sorbent resin is mixed with a known concentration of Zn(II) ions. In order to attain the maximum metal ion complexation capacity; the filter was optimized to the optimum separation/pre-concentration conditions of analytes, including the effect of pH, capacity of the solid, equilibration time and coexisting ions; afterwards, the solution was filtered. The amount of zinc metal ion complexed/adsorbed was determined by the difference between the initial concentration in aqueous solution and that found in the supernatant, using flame atomic absorption. The optimum condtions (maximum uptake) was obtained at pH = 6 using 30 min shaking time, and the capacity of the solid was 0.153 mmol Zn/g. Conclusion: The ligand was successfully trapped inside the sol-gel pores, and no diffusion of the ligand was observed. Soaking of the sorbent in a solution containing Zn(II) ions results in diffusion of the zinc ions through the sorbent pores into the ligand for complexation.

Determination of 9 residual acrylic monomers in acrylic resins by gas chromatography-mass spectrometry coupled with microwave assisted extraction

A reliable gas chromatography-mass spectrometry (GC-MS) method was developed for the determination of 9 residual acrylic monomers (methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl acrylate, butyl methacrylate, styrene, acrylic acid and methacrylic acid) in acrylic resins. Solid resin was precipitated with methanol after microwave assisted extraction with ethyl acetate for 30 min, and liquid resin was diluted with methanol directly. The nine acrylic monomers got a good separation within 20 min on a DB-WAX column. The limits of quantification (LOQs, S/N = 10) of the method were in the range of 1-10 mg/kg for liquid resin and 3-50 mg/kg for solid resin. The calibration curves were linear within 1-500 mg/L range with correlation coefficients above 0. 995. The recoveries ranged from 84.4% to 108.6% at five spiked levels. The sensitivity, recovery and selectivity of the method can fully meet the requirements of practical work.

Hydrodynamics Studies in a Liquid Solid Circulating Fluidized Bed of Varying Liquid Viscosity

To design an industrial liquid solid circulating fluidized bed system properly, it is important that the hydrodynamics be studied first. So far investigations have been carried out in a liquid solid circulating fluidized bed (LSCFB) with tap water as the liquid phase. There is still limited understanding on how particles are circulated in LSCFB with viscous fluids. The aim of our work was to characterize the hydrodynamics in a LSCFB with varying viscosity. Experiments were conducted in a fluidized bed riser of 0.1 m diameter by 2.4 m height with different viscous liquids, to study its effects of operating parameters namely; primary velocity, secondary velocity, total velocity, on the hydrodynamics characteristics of the LSCFB in terms of solid holdup, solid circulation rate and particle velocity. Experiments were conducted using water and glycerol at different concentration. The solid particle resin of 0.5 mm diameter was used for the experiment. The results indicate that the solid hold up in the riser is axially uniform for viscous liquids and increases with increase in auxiliary velocity. The average solid holdup found to decrease with increase in total velocity and increases with increase in liquid viscosity as the critical transitional velocity decreases with the increase in viscosity. The solid circulation rate is found to increase with increase in total velocity and auxiliary velocity, and also increases with increasing viscosity.

Nanostructured coating based on epoxy/metal oxides: Kinetic curing and mechanical properties

In this work nanocomposites were prepared by means of a twin-screw extruder using a solid epoxy resin DGEBA/biguanidine matrix and metal oxides filler. Two different nanoparticles were employed as-received, alumina and zinc oxide at the composition of 3% phr in both cases. Cure kinetics analysis was investigated by means of DSC in a set of non-isothermal experiments. In the neat polymer, the activation energy of the curing reaction was 65kJ/mol, whereas after adding ZnO, a minimum of 53kJ/mol was reached. The lower activation energy of this nanocomposite allows longest reaction and consequently enhanced crosslinking network. Thus, the glass transition temperature is increased from 368K in the neat polymer to 377K after reinforcement. The nanocomposite filled with alumina has corresponding activation energy of 61kJ/mol, in this case, short chain segments must possess higher reticulation near to surface particles, influenced by the presence of hydroxyl groups. The mechanical properties were examined by means of instrumented indentation and scratch test. An increase of around 10% of the elastic modulus and hardness was observed. Toughening mechanisms are induced by alumina, as observed by the scratch test, nevertheless, zinc oxide increased the matrix fragility because to its catalytic influence on cure reaction. In addition dispersion state of the particles into the nanocomposites was investigated. Finally, connections between cure kinetic, interphase and mechanical properties in this system are addressed.

Polymerization of α-pinene using Lewis acidic ionic liquid as catalyst for production of terpene resin

The polymerization of α-pinene was investigated in the presence of Lewis acidic ionic liquids (ILs). The results indicated that ILs 1-(1-ethyl acetate-yl)-3-methylimidazolium chloroaluminates ([EtOCOCH2-mim]Cl-AlCl3), especially molar fraction of AlCl3x = 0.67, had excellent catalytic performance for the polymerization of α-pinene. The yield and softening point of solid resin reached to 52.0% and 115 °C, respectively, when the polymerization was carried out at −5 °C for 4 h. IL was reused for five times without a decrease in the catalytic performance. Compared with the traditional catalyst AlCl3, IL exhibited some advantages such as simplicity and efficiency of the product isolation, higher yield and softening point of the product, and excellent reusability.

A comparison of Boc and Fmoc SPPS strategies for the preparation of C‐terminal peptide α‐thiolesters: NY‐ESO‐1 39Cys‐68Ala‐COSR

The synthesis of a polypeptide derived from the cancer testis antigen NY-ESO-1 bearing a C-terminal α-thiolester is described. Employing tert-butyloxycarbonyl solid phase peptide synthesis the thiolester moiety was installed on-resin using a mercaptopropionic acid linker, thereby requiring no post synthetic manipulations and delivering the requisite α-thiolester polypeptide after cleavage from the resin with HF. Several 9-fluorenylmethyloxycarbonyl solid phase peptide synthesis approaches whereby the thiolester was required to be introduced in a post synthesis manner were examined concurrently. These comprised syntheses on two different "safety catch" linkers, an N-alkyl-N-acyl sulphonamide and an N-acyl benzimidazolone wherein the thiolester is generated from an activated precursor. The condensation of a mercaptan with the C-terminal carboxylate in a direct thiolesterification reaction was also examined. When using either of the three 9-fluorenylmethyloxycarbonyl-based approaches, the linear polypeptide could be assembled straightforwardly on the solid phase resin; however, a thiolesterification of the C-terminal carboxyl of the fully side chain protected peptide proved to be the most effective post-assembly method for the installation of the C-terminal thiolester.

Modified coatings based on chlorosulfonated polyethylene

The results of investigations of the effect of solid petroleum resins, epoxide oligomers, and type of curing agent upon the properties of varnishes and coatings based on chlorosulfonated polyethylene are given. It is shown that the use of cycloaliphatic isocyanates and amine-containing organic silicon compounds allows one to obtain coatings with a complex of high processing and operating characteristics.

Supercapacitor performance of hollow carbon spheres by direct pyrolysis of melamine-formaldehyde resin spheres

The nitrogen and oxygen co-doped hollow carbon spheres(HCSs) were prepared via a simple pyrolysis of solid melamine-formaldhyde resin spheres. The carbonization temperature has an important influence on the specific surface area, pore-size distribution and heteroatom contents of HCSs. The synergistic effects of those physical and chemical properties on supercapacitor performance were systematically investigated. Among the HCSs obtained at different temperatures, HCSs-800(co-doped HCSs at 800 °C) exhibits the best reversible specific capacitance in 2 mol/L H2SO4 electrolyte and meanwhile maintains a high-class capacitance retention capability. The nitrogen heteroatoms were confirmed to play a crucial role in improving capacitance in an acid medium. This kind of nitrogen doped HCSs is a potential candidate for an efficient electrode material for supercapacitors.

Preparation and characterization of phenolic foams with eco-friendly halogen-free flame retardant

The high solid resol phenolic resin was prepared via step polymerization of formaldehyde, paraformaldehyde, and phenol using sodium hydroxide and calcium oxide as catalysts, and employed to prepare the phenolic foams (PFs) by the introduction of retardant additives including eco-friendly halogen-free flame retardants (ammonium polyphosphate), char-forming agents (pentaerythritol), and synergists (zinc oxide, molybdenum trioxide, cuprous chloride, and stannous chloride). The effects of these additives on flame retardancy, heat resistance, and fire properties of flame-retardant composite phenolic foams (FRCPFs) were evaluated by limiting oxygen index (LOI) tests, thermogravimetric analyzer, and cone calorimeter tests. It was found that the flame retardan significantly increased the LOIs of FRCPFs. Compared with PF, heat release rate, total heat release, effective heat of combustion, production or yield of carbon monoxide (COP or COY), and Oxygen consumption (O2C) of FRCPFs all remarkably decreased. However specific extinction area and total smoke release significantly increased, which agreed with the gas-phase mechanism of the flame-retardant system. The results indicate that FRCPFs have excellent fire-retardant performance and less smoke release. APP/PER/ZnO is shown to be better flame-retardant system for PFs.