Alcohol Composites Research Articles

Fluorous‐Phase‐Based Chiral Assay with Circular Dichroism Spectroscopy

A highly fluorinated molecular probe made of a salicylaldehyde derivative is designed and synthesized for the detection of chiral amines in the fluorous phase. When treated with various chiral amines in a fluorous solvent (perfluorohexyl ethanol), this probe shows intense CD signals at wavelengths greater than 400 nm, which has been used to determine the enantiomeric composition of chiral amines, amino alcohols, and amino acids. This is the first example of CD recognition of chiral compounds that is conducted in the fluorous phase. The approach could greatly reduce the undesired interference in the direct assay of asymmetric reactions and catalytic processes.

Effect of the Coagulation Bath on the Structure and Mechanical Properties of Gel-Spun Lignin/Poly(vinyl alcohol) Fibers

Gel spinning was investigated as an alternative approach to the melt spinning of lignin-based fibers. Lignin/poly(vinyl alcohol) (PVA) composites with various weight percentages of lignin were gel-spun into high-strength fibers. Although lignin is an amorphous biopolymer, incorporation of the rigid filler enhanced the mechanical properties of the PVA fibers and affected their structure. Lignin stabilized the gel structure of the thermoreversible PVA gel, as noted by higher gel melting temperatures. Methanol/acetone coagulation baths with high acetone content rendered the gel-spun fibers more drawable, helped to maintain lignin within the gel fibers, and increased the gel melting point. The best mechanical performance was observed for fibers containing 5% lignin, which had an average tensile strength of 1.1 GPa, a Young’s modulus of 37 GPa, and a toughness of 17 J/g. Structural analysis of the 5% lignin fibers showed them to possess the highest index of PVA crystallinity. The fibers were more drawable at h...

Biomimetic Chirality Sensing with Pyridoxal-5'-phosphate.

Pyridoxal-5'-phosphate (PLP) is introduced to a biomimetic indicator displacement assay for simultaneous determination of the absolute configuration, enantiomeric composition and concentration of unprotected amino acids, amino alcohols and amines. The chiroptical assay is based on fast imine metathesis with a PLP aryl imine probe to capture the target compound for circular dichroism and fluorescence sensing analysis. The substrate binding yields characteristic Cotton effects that provide information about the target compound ee and the synchronous release of the indicator results in a nonenantioselective off-on fluorescence response that is independent of the enantiomeric sample composition and readily correlated to the total analyte concentration.

Aromatic compounds and organoleptic features of fermented wolfberry wine: Effects of maceration time

ABSTRACTThis study investigated the effect of maceration time on the physicochemical properties and aromatic composition of fermented wolfberry wine. Results showed that middle-time maceration (MM) wine showed higher level on physicochemical features. Esters contributed the most to the overall aroma of wolfberry wine, and its highest level was observed in MM wine. Difference maceration time altered the composition of acids, alcohols, aldehydes, and ketones in wine. Maceration did not alter the level of methionol, whereas MM caused a highest level of 4-vinylguaiacol in wine. Sensory evaluation revealed that MM provided wine with better flavor complexity and fruity notes.

Hazardous substances in homemade alcohol in rural areas of Limpopo province, Republic of South Africa: a public health concern

ABSTRACTThe unsafe use of alcohol has now become one of the most vital risks to health. The study aimed at exploring and describing the concoctions of unsafe substances in the homemade alcohol in the rural areas. Explorative, descriptive and contextual designs were used. Purposive and snowball sampling methods were also used to select the 76 participants. Data was collected through interviews with brewers and consumers of the homemade alcoholic beverages. Thematic analysis was used. Findings indicate that foreign substances such as methylated spirits, brake fluids and battery acid were added to the homemade alcohol for commercial reasons in a way to address poverty and unemployment. The availability, accessibility, affordability and acceptability of the homemade alcohol influenced the drinking patterns. Further information is needed on the chemical composition of the homemade alcohol and its subsidiary social and health effects. It is recommended that practitioners across the disciplines in public health ...

Investigation of the lamination of electrospun graphene-poly(vinyl alcohol) composite onto an electrode of bio-electro-Fenton microbial fuel cell

The bio-electron-Fenton system integrates microbial fuel cell and Fenton process into a single system to destroy the organic and bio-refractory contaminants in wastewater. Its performance is closely dependent on the sufficient electron supplement by the oxidation process in anode chamber and the reduction process in cathode chamber. This article presents a novel cathode of a bio-electron-Fenton system which can simultaneously achieve good electron supplement and the wastewater treatment in cathode chamber. The cathode consists of indium-tin-oxide conductive glass on which layers of graphene-poly(vinyl alcohol) composite are sprayed by electrospinning. The material characterization is verified by Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. The voltage, current, and power density of the system are verified by cyclic voltammetry. The wastewater treatment is verified by dye decolorization. With the addition ratio of 4 wt% graphene, the system achieves the optimal power density of 74.1 mW/m2, open-circuit voltage of 0.42 V, and the decolorization of reactive black 5 of 60.25%. By constant-resistance discharge testing within three-cycle, the system can stably supply a maximum voltage of 0.41 V or above. Hence, the proposed electrospun graphene-poly(vinyl alcohol) composite cathode electrode can not only improve the power-supply efficiency but also enhance the efficiency of wastewater treatment.

Ionic liquids that form adducts with alcohols

Ionic liquids bearing an activated carbonyl group in the cation are shown to form adducts with alcohols without the aid of any catalysts. How these functionalised ionic liquids could be used in altering vapour phase compositions of alcohols and in alcohol separations are demonstrated.

High Capacity Sulfurized Alcohol Composite Positive Electrode Materials Applicable for Lithium Sulfur Batteries

New sulfur-carbon composite positive electrode materials were synthesized through sulfurizing primary alcohols, and their electrochemical properties were examined. The sulfurized alcohol composites (SACs) showed relatively higher sulfur contents (more than 60 wt%) and were revealed to be an amorphous structure by high-resolution TEM observations. Raman and XAFS spectra showed the presence of S – S, C – S, and C – C bonds, and the C – C bonds mainly consisted of sp3 components, which makes a clear contrast to the previously reported organosulfur materials where the C – C bonds mainly consisted of sp2 components. The SAC positive electrode cells showed discharge capacities of more than 900 mAh·g−1 with relatively reduced cycle degradation.

Tubular polyvinyl alcohol composites used as vascular grafts: Manufacturing techniques and property evaluations

This study aims at developing biodegradable vascular grafts by combining PVA knits and porous polyvinyl alcohol PVA hydrogels. The proposed tubular PVA composites are compared to the commercially available vascular grafts in terms of compliance that best matches the compliance of natural vessels. The warp knits and weft knits are first evaluated for their circumferential properties, while the hydrogels are examined for their porous structure. The tubular PVA composites containing knits and hydrogels are then tested for variations in their diameter and compliance. The results indicate that the weft knits exhibit greater circumferential deformation. Moreover, vascular grafts composed of weft knits also have a higher porous connectivity and compliance that matches native vessels.

Composition of Unrecorded Distilled Alcohol (bai jiu) Produced in Small Rural Factories in Central China.

BackgroundUnrecorded traditional distilled spirits (bai jiu, 白酒) are made and used throughout rural China for everyday use and special occasions. Nearly every town or village has a distiller to supply the demand. In rural China, distilling bai jiu is legal and regulated lightly or not at all. The World Health Organization estimates that as much as 25% of all alcohol consumed in China is unrecorded alcohol, of which an unknown portion is unrecorded bai jiu. Little is known about the composition of unrecorded Chinese spirits from rural parts of the country. This study focused on white spirits because the high ethanol (EtOH) concentration makes them more likely to contribute to health risks compared to other types of lower alcohol by volume (ABV) Chinese unrecorded alcohol.MethodsResearchers purchased samples of Chinese white spirits from small‐factory distillers in central China. An independent laboratory conducted the analysis. Alcohol strength (ABV) was determined by hydrometer. Gas chromatography was used to determine the concentration of volatile organic compounds: EtOH, methanol, acetaldehyde, ethyl acetate, and higher alcohols. Samples were tested for 3 heavy metals—arsenic, cadmium, and lead. We used the guidelines developed by the Alcohol Measures for Public Health Research Alliance (AMPHORA) of the European Commission to assess risk.Results ABV ranged from 35.7 to 61.4%, and 58 of the 61 samples exceeded 40% ABV. The concentration of methanol, ethyl acetate, lead, arsenic, and cadmium was below AMPHORA guideline. The sum of higher alcohols exceeded the AMPHORA maximum in just 1 sample. Forty of the 61 samples had acetaldehyde levels beyond the AMPHORA guideline.ConclusionsThe unrecorded Chinese alcohols we analyzed had a high EtOH concentration—a public health concern that is also presented by recorded alcohols. The high percentage of samples (65.5%) that had elevated acetaldehyde suggests the need to investigate the causes for this result and the need for steps to reduce acetaldehyde levels. The cumulative long‐term risks of using high EtOH and high acetaldehyde Chinese spirits are heightened by the percentage of people in China who have a genetic trait for impaired acetaldehyde metabolism.

Adsorption and oxidation study on arsenite removal from aqueous solutions by polyaniline/polyvinyl alcohol composite

In this study, the Polyaniline/Polyvinyl Alcohol (PANi/PVA) composite was examined for arsenite (As(III)) removal from aqueous solution. The effect of several parameters including PVA concetration (0–5g/L), pH (1–13), adsorbent dosage (0.5–6g/L), contact time (0–120min), initial As(III) concentration (0.5–100mg/L), and As(III) oxidation were evaluated on the adsorption efficiency. The results indicated that PVA has an effective role in increasing adsorptive capacity of PANi, by changing its morphology and extending its active surface sites. The adsorption process was pH dependent and As(III) removal consistently improved by increasing solution pH. Adsorption reached equilibrium within 1h and Kinetics study showed that the adsorption process followed the pseudo-second-order rate model. Maximum arsenite removal efficiency was obtained when 2g/L of PANi/PVA was added to the solution. The equilibrium adsorption data were well fitted to Langmuir isoterm model, and the maximum adsorption capacity of arsenite was 27.25mg/g. Furthermore, arsenite oxidation led to 65% adsorption enhancement at the neutral aqueous system and also decreased the sensitivity of adsorption to pH.

Fabrication and characterization of Ag doped hydroxyapatite-polyvinyl alcohol composite nanofibers and its in vitro biological evaluations for bone tissue engineering applications

Electrospinning is one of the promising techniques to fabricate the nanofiber based scaffold for bone regeneration applications. In this study, firstly sol–gel method was employed to synthesize 5 % of Ag doped hydroxyapatite and also 10 wt% of polyvinyl alcohol solution was prepared for the electrospun process. For the first time, we have successfully fabricated the composite nanofibers in the combination of various concentration of Ag doped hydroxyapatite such as 1, 2, 3, and 5 wt% with polyvinyl alcohol solution. The developed Ag doped hydroxyapatite-polyvinyl alcohol composites were further characterized by Fourier transform infrared spectroscopy and powder-X-ray diffraction analysis to examine the characteristic functional groups and phase composition of Ag doped hydroxyapatite embedded into polyvinyl alcohol matrix. The uniform distribution of Ag doped hydroxyapatite in polyvinyl alcohol polymer with nanofiber diameter of 188–242 nm range was confirmed by high resolution transmission electron microscope and dynamic light scattering analysis, also the chemical/elemental composition was observed by scanning electron microscopy-energy dispersive spectroscopy analysis. The antibacterial activity was evaluated for the fabricated Ag doped hydroxyapatite polyvinyl alcohol composite nanofibers by using Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) pathogens and the results demonstrated that E. coli exhibits excellent zone of inhibition than S. aureus due to its lesser cell wall thickness. The hemocompatibility study proves that the developed composite nanofibers are blood compatible and showed the hemolytic ratio of less than 5 %. In addition to this, in vitro bioactivity assessment was carried out for 7 days by immersing in simulated body fluid solution to generate the dense apatite layer on their surfaces which was further examined by X-ray diffraction and scanning electron microscopy-energy dispersive spectroscopy analysis. Hence, these electrospun fabricated Ag doped hydroxyapatite-polyvinyl alcohol composite nanofibers will acts as a potential scaffold material for tissue engineering applications. Graphical abstract of electrospun fabrication of Ag@HAP-PVA composite nanofibers and its in vitro biological evaluations.

Dielectric relaxation and ac conductivity behavior of carboxyl functionalized multiwalled carbon nanotubes/poly (vinyl alcohol) composites

We study the dielectric relaxation and ac conductivity behavior of MWCNT-COOH/Polyvinyl alcohol nanocomposite films in the temperature (T) range 303–423K and in the frequency (f) range 0.1Hz–1MHz. The dielectric constant increases with an increase in temperature and also with an increase in MWCNT-COOH loading into the polymer matrix, as a result of interfacial polarization. The permittivity data were found to fit well with the modified Cole-Cole equation. Temperature dependent values of the relaxation times, free charge carrier conductivity and space charge carrier conductivity were extracted from the equation. An observed increment in the ac conductivity for the nanocomposites was analysed by a Jonscher power law which suggests that the correlated barrier hopping is the dominant charge transport mechanism for the nanocomposite films. The electric modulus study revealed deviations from ideal Debye-type behavior which are explained by considering a generalized susceptibility function. XRD and DSC results show an increase in the degree of crystallinity.

Lipid turnover reflects life-cycle strategies of small-sized Arctic copepods

This study aimed at understanding how life-cycle strategies of the primarily herbivorous Pseudocalanus minutus and the omnivorous Oithona similis are reflected by their lipid carbon turnover capacities. The copepods were collected in Billefjorden, Svalbard, and fed with 13C labeled flagellates and diatoms during 3 weeks. Fatty acid (FA) and fatty alcohol compositions were determined by gas chromatography, 13C incorporation was monitored using isotope ratio mass spectrometry. Maximum lipid turnover occurred in P. minutus, which exchanged 54.4% of total lipid, whereas 9.4% were exchanged in O. similis. In P. minutus, the diatom markers 16:1(n-7), 16:2(n-4) and 16:3(n-4) were almost completely renewed from the diet within 21 days, while 15% of the flagellate markers 18:2(n-6), 18:3(n-3) and 18:4(n-3) were exchanged. In O. similis, 15% of both flagellate and diatom markers were renewed. P. minutus exhibited typical physiological adaptations of herbivorous copepod species, with a very high lipid turnover rate and the ability to integrate FAs more rapidly from diatoms than from flagellates. O. similis depended much less on lipid reserves and had a lower lipid turnover rate, but was able to ingest and/or assimilate lipids with the same intensity from various food sources, to sustain shorter periods of food shortage.

Poly-paper: a sustainable material for packaging, based on recycled paper and recyclable with paper.

Until now, environmental sustainability issues are almost entirely unsolved for packaging materials. With the final aim of finding materials with a single recycling channel, cellulose fiber/poly(vinyl)alcohol composites were investigated. After extrusion and injection molding, samples of composite with different cellulose fiber content (30%, 50% and 70% w/w) were tested. Tensile mechanical tests exhibited an improvement in composite stiffness when the reinforcement content was increased together with a decrease in composite elongation. Solubility tests performed at room temperature and 45°C showed different behavior depending on the water-resistant film applied on the composite (50% cellulose fiber content). In particular, the uncoated composite showed complete solubility after 2 hours, whereas at the same time point, no solubility occurred when a non-water-soluble varnish was used. The proposed composites, named Poly-paper, appear to warrant further investigation as highly sustainable packaging.

Hybridization of α-zirconium phosphate with hexachlorocyclotriphosphazene and its application in the flame retardant poly(vinyl alcohol) composites

A planar-like inorganic α-zirconium phosphate (α-ZrP) particles were modified by a kind of cyclophosphazene derivative via three-step hybridization method, first modified by melamine (MA), then combined with hexachlorocyclotriphosphazene (HCCP) through nucleophilic substitution and further integrated with excessive MA. Thus, a hybrid flame retardant (HAC) was successfully synthesized. The composites based on poly(vinyl alcohol) (PVA) and HAC were prepared by solution blending. The thermal, mechanical properties and flame retardancy of the composites were studied. It was found that HAC showed a catalytic effect in the initial decomposition stage and promoted the formation of char at high temperatures. When the content of HAC was 15 wt%, the limiting oxygen index (LOI) reached 28.4% and classified V-0 rating, whereas with the same content of fire retardant, for PVA/α-ZrP and PVA/product of MA with HCCP composites (one kind of intumescent flame retardant IFR), the LOI values were only 24.7% and 27.1%, respectively. The combination of IFR and α-ZrP could remarkably improve the yield and graphitization of char residues, make the char more stable, compact and continuous, inhibiting underlying PVA from contacting heat and oxygen. Moreover, the mechanical properties could be reinforced and toughened with certain content of HAC.

Ultrasound-Responsive Behavior of Gelatinous Ionic Liquid/Poly(vinyl alcohol) Composites

Poly(vinyl alcohol)/ionic liquid (PVA/[BMI]Cl) gelatinous composites were prepared and used to study ultrasound (US)-responsive behavior in the shear viscosity, viscoelasticity, and Fourier transform infrared (FT-IR) spectra before and after 43 kHz of US exposure. PVA compounds with different molecular weights were mixed with imidazole ionic liquid in aqueous solution to form a gelatinous complex. The shear viscosity and viscoelasticity of PVA/[BMI]Cl composites decreased under US exposure and increased gradually to the original value after the removal of US exposure. The FT-IR results showed that the US enhanced the intensities of the OH stretching region in 3000–3600 cm–1. Two-dimensional correlation spectroscopy and deconvolution of the FT-IR spectra suggested that US exposure deformed hydrogen bonds in the composites of PVA/[BMI]Cl. These results showed that hydrogen bonds formed between [BMI]Cl and PVA were broken by US exposure. As a result, the composites of PVA/[BMI]Cl could respond to US exposure.

In Situ Reduction of Graphene Oxide Nanosheets in Poly(vinyl alcohol) Hydrogel by γ-Ray Irradiation and Its Influence on Mechanical and Tribological Properties

Graphene-oxide-containing poly(vinyl alcohol) (PVA/GO) composites prepared by the freeze–thaw method were irradiated by γ-rays at doses of 50, 100, 150, and 200 kGy to improve their strength and wear resistance. The effects of irradiation dose on the mechanical, thermal, and tribological properties were evaluated. The microstructure and composition of the PVA/GO hydrogels before and after irradiation were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The results reveal that the irradiation can reduce the GO sheets dispersed in the PVA matrix in situ and that the reduced graphene oxide acts as the cross-linking point of the dangling bonds between molecular chains and forms covalent bonds after γ-ray irradiation, which endows the composites with high strength and improved thermal stability. Compa...

Mechanical properties of heat-treated cellulose nanofiber-reinforced polyvinyl alcohol nanocomposite

The mechanical properties of cellulose nanofiber-reinforced polyvinyl alcohol composite were studied. Neat polyvinyl alcohol films, cellulose nanofiber sheets, and their nanocomposites containing cellulose nanofiber weight ratios of 5, 15, 30, 40, 45, 50 and 80 wt% were fabricated. Heat treatment by hot pressing at 180℃ was conducted on the specimens to study its effect to the mechanical properties and the results were compared with the non heat-treated specimens. Morphology of the composites was studied by scanning electron microscopy and the mechanical properties were evaluated by means of tensile tests. The results showed that increase of cellulose nanofiber content from 5 wt% to 80 wt% has increased the tensile strength of the composites up to 180 MPa, with cellulose nanofiber content higher than 40 wt% yielding higher tensile strength. The heat-treated specimens exhibited higher tensile strength compared to those of untreated specimens.

A Systematic Method for the Development of Operating Policies for Two-Step Processes with Semibatch Reactive Distillation

Semibatch reactive distillation (SBRD) is a variation on batch reactive distillation (BRD) in which one reactant or an entrainer is fed to the process continuously during the batch. Qi and Malone (Qi, W; Malone, M. F. Semibatch Reactive Distillation for Isopropyl Acetate Synthesis. Ind. Eng. Chem. Res. 2011, 50, 1272–1277) suggested SBRD for the synthesis of isopropyl acetate with acetic acid fed continuously at the top of the column to reduce the composition of the alcohol in the distillate product. The distillate product from the SBRD is a mixture of water and ester which can subsequently be separated by inverted batch distillation (IBD). The optimization of such a two-step batch process involves trade-offs between the two steps (SBRD and IBD). In this work, an algorithm for systematic design of such processes is developed and applied to processes for the synthesis of isopropyl acetate and ethyl acetate. The key variable connecting the two batch steps is the composition of alcohol in the SBRD distillate product. Allowing a higher alcohol composition makes SBRD operation easier but IBD operation more difficult. The algorithm identifies the alcohol concentration which minimizes total process time, which is closely related to energy consumption, as well as side feed flow rate and reflux ratio profiles during the batches.