Addition Of Alcohol Research Articles

Polymerization of six-membered propylene oxalate

Ring-opening polymerization (ROP) of the six-membered cyclic propylene oxalate was studied for the first time. The reaction proceeded with a high limiting conversion of about 96 % at 100 °C in the presence of tin(II) octoate. Linear macromolecules, Mw of 20–30 × 103, Ð ∼ 2, represented 86 % of the product, 4 % came from the equilibrium concentration of monomer, while the rest 10 % were cyclic oligomers consisting of 3–10 repeat units. ROP was accompanied by partial (about 30 %) conversion of the catalyst into the insoluble tin(II) oxalate in the course of polymer cross-linking reaction. The kinetics of polymerization obeyed first-order law, indicating typical for ROP constant number of active centers during the process. Polymerization without catalyst was 2000 times slower and also resulted in formation of polymer with Ð ∼ 2. Addition of benzyl alcohol to the polymerization mixture resulted in its inclusion into linear macromolecules and a decrease in their molecular weight. The results point to the possibility of synthesizing propylene oxalate block copolymers using macroinitiators with hydroxyl end groups.

Aggregation behavior, interaction forces and physico-chemical parameters of cetyltrimethylammonium chloride in aqueous solution of bovine serum albumin: Impacts of short-chain alcohols and temperature

To better understand the molecular interactions between cetyltrimethylammonium chloride (CTAC) and bovine serum albumin (BSA), we report the alteration of the physicochemical characteristics of CTAC in aqueous BSA solutions in the presence of different alcohols. The analyses were performed using the conductivity method at temperatures ranging from 298.15 to 323.15 K, with 5 K intervals. The critical micelle concentration (CMC) values of the BSA + CTAC systems were found to change with variations in alcohol types, solvent compositions, and temperatures. The CMC values grew with the rising of alcohol contents. The negative free energy changes (∆Gm0) indicated the spontaneous association of the systems in all solvents media. The magnitudes of ∆Hm0 and ∆Sm0, determined from the micellization of the systems, indicated the presence of electrostatic, ion-dipole, and hydrophobic forces. The thermodynamics of transfer (free energy (∆Gm,tr0), enthalpy (∆Hm,tr0), entropy (∆Sm,tr0)), and compensation parameters (∆Hm0,∗ and Tc)—were also calculated, which provided significant insights into the potential interactions between CTAC and BSA in the presence of various alcohol additives. Furthermore, molecular docking studies suggested the binding of CTAC to different BSA binding sites with varying affinities.

Investigation of high percentage of dimethyl ether on biodiesel usage in a diesel engine

Demand for cleaner energy sources both as additive and alternative fuels that can substitute or contribute to the usage of conventional fuels is growing. Researchers have mainly focused on improving or finding a renewable fuel from vegetable oil or addition of chemicals and alcohols for IC engine. This study analyzed the effects of a high percentage of dimethyl ether (DME) combined with biodiesel in a diesel engine. Transesterification method was selected for conversion of pure safflower oil to biodiesel. DME was blended with biodiesel at concentrations of 50% and 25% on a volume basis, respectively. Engine performance and emissions tests demonstrated that the thermal efficiency values were increased at high load operation when the engine was fueled with high percentage of DME. Furthermore, compared to conventional diesel, there has been a notable decrease in NOx emissions. Nevertheless, the introduction of DME blend had negligible effects on CO2 emissions. However, when using a high ratio of DME blend, HC emissions were found to increase, whereas a low ratio of DME blend resulted in decreased HC emissions. Apart from these, some irregularities were observed both on heat release rate and cylinder pressure especially for 50% of DME usage. Finally, the values for both brake-specific fuel consumption and mass fuel of DME-blended fuels were deteriorated.

A novel formulation of an eco-friendly calcium nitrate-based heavy completion fluid

Calcium-nitrate-based transparent completion fluids are widely used in the oil and gas industry for well completion and stimulation operations in carbonate reservoirs. These fluids have many advantages, such as medium density, low corrosion, good temperature stability, low clay swelling, and high wettability. However, the density of calcium nitrate brine is limited by its solubility, which can be increased by the addition of alcohols. This study investigated the effects of adding different types of alcohols (G1, G2, and G3) to calcium nitrate brine on the properties and performance of the completion fluid for carbonate reservoirs. The fluid properties and performance were evaluated through a series of laboratory tests, including density measurement, corrosion test, viscosity measurement, rheology test, temperature stability test, clay swelling test, wettability test, and compatibility test. The results showed that the addition of alcohols to brine can improve or reduce the fluid density, viscosity, corrosion, temperature stability, clay swelling, wettability, and compatibility, depending on the type and amount of alcohols. The optimum fluids have been selected based on their highest density, lowest viscosity, lowest corrosion, highest temperature stability, lowest clay swelling, highest wettability change, and highest compatibility with formation fluids. The densities of the fluids CN4, CNG14, CNG24, and CNG34 were respectively 96, 101, 101.5, and 100 pounds per cubic foot (pcf). Their rates of corrosion on L80 steel were respectively 0.829, 0.589, 0.720, and 0.599 mils per year (mpy). Their apparent viscosities at 62.4 °F were respectively around 15, 120, 100, and 60 centipoise (cp). Their apparent viscosities at 176 °F were all around 10 to 25 mpy. The fluids remained clear with no evidence of suspended solid particles at 20 °F, indicating their resilience to low-temperature conditions and suitability for use in cold weather operations. The fluid CNG24 becomes cloudy at 285 °F, and the fluid CNG34 becomes cloudy from 212 °F onward, but the CN4 fluid remains clear and transparent at all temperatures. In the tested high temperatures, the effect on their pH was around the same. The fluids CN4, CNG24, and CNG34 had a lower swelling index than 5 ml per 2 g of bentonite clay. The contact angles of oil and carbonate-type thin sections after their wettabilities were affected by the fluids were also 99.5, 36.54, and 46.03°, respectively. Finally, they’re all relatively compatible with formation fluids. The best completion fluid for carbonate reservoirs was CNG24, which contained calcium nitrate and G2 alcohol. This fluid had the best overall performance and safety of the fluids tested.

Double cross-linked chitosan sponge encapsulated with ZrO2/soy protein isolate amyloid fibrils nanoparticles for the fluoride ion removal from water

Fluoride ion pollution in water has become a serious threat to the water environment and human health. Adsorption is a promising means of fluoride removal, but it also faces challenges such as the difficult separation and recovery of powdered particles, the leaching of modified coatings from adsorbents, and the structural disintegration of macroscopic adsorbents. For addressing the above challenges, glutaraldehyde/polyvinyl alcohol co-crosslinked ZrSAF/chitosan spongy composites (ZrS/GPCS) were prepared by utilizing encapsulation strategies and cross-linking. ZrS/GPCS-1, ZrS/GPCS-3 and ZrS/GPCS-4 were prepared due to the different amounts of cross-linking agents. The results showed that their fluoride ion adsorption capacities were 42.02, 44.44 and 39.84 mg/g, respectively. The removal of fluoride ions by ZrS/GPCS was maintained at >80 % in the pH range of 4–10. The addition of glutaraldehyde and polyvinyl alcohol affected the contact efficiency of fluoride ions with chitosan and ZrSAF, influencing the adsorption rate and adsorption effect. Glutaraldehyde, polyvinyl alcohol and ZrSAF improved the thermal stability, mechanical properties and structural integrity of chitosan matrix. Both the chitosan matrix and the internal ZrSAF played an important role in fluoride removal, and the removal mechanisms included electrostatic interaction, hydrogen bonding, and complexation.

Alcohols as Biofuel for a Diesel Engine with Blend Mode—A Review

In the era of decarbonization driven by environmental concerns and stimulated by legislative measures such as Fit for 55, the industry and transportation sectors are increasingly replacing petroleum-based fuels with those derived from renewable sources. For many years, the share of these fuels in blends used to power compression ignition engines has been growing. The primary advantage of this fuel technology is the reduction of GHG emissions while maintaining comparable engine performance. However, these fuel blends also have drawbacks, including limited ability to form stable mixtures or the requirement for chemical stabilizers. The stability of these mixtures varies depending on the type of alcohol used, which limits the applicability of such fuels. This study focuses on evaluating the impact of eight types of alcohol fuels, including short-chain (methanol, ethanol, propanol) and long-chain alcohols (butanol, pentanol, hexanol, heptanol, and octanol), on the most critical operational parameters of an industrial engine and exhaust emissions. The engines being compared operated at a constant speed and under a constant load, either maximum or close to maximum. The study also evaluated the effect of alcohol content in the mixture on combustion process parameters such as peak cylinder pressure and heat release, which are the basis for parameterizing the engine’s combustion process. Determining ignition delay and combustion duration is fundamental for optimizing the engine’s thermal cycle. As the research results show, both the type of alcohol and its concentration in the mixture influence these parameters. Another parameter important from a usability perspective is engine stability, which was also considered. Engine performance evaluation also includes assessing emissions, particularly the impact of alcohol content on NOx and soot emissions. Based on the analysis, it can be concluded that adding alcohol fuel to diesel in a CI engine increases ignition delay (up to 57%), pmax (by approximately 15–20%), HRRmax (by approximately 80%), and PPRmax (by approximately 70%). Most studies indicate a reduction in combustion duration with increasing alcohol content (by up to 50%). For simple alcohols, an increase in thermal efficiency (by approximately 15%) was observed, whereas for complex alcohols, a decrease (by approximately 10%) was noted. The addition of alcohol to diesel slightly worsens the stability of the CI engine. Most studies pointed to the positive impact of adding alcohol fuel to diesel on NOx emissions from the compression ignition engine, with the most significant reductions reaching approximately 50%. Increasing the alcohol fuel content in the diesel blend significantly reduced soot emissions from the CI engine (by up to approximately 90%).

Structure-driven development of a biomimetic rare earth artificial metalloprotein

The 2011 discovery of the first rare earth-dependent enzyme in methylotrophic Methylobacterium extorquens AM1 prompted intensive research toward understanding the unique chemistry at play in these systems. This enzyme, an alcohol dehydrogenase (ADH), features a La3+ ion closely associated with redox-active coenzyme pyrroloquinoline quinone (PQQ) and is structurally homologous to the Ca2+-dependent ADH from the same organism. AM1 also produces a periplasmic PQQ-binding protein, PqqT, which we have now structurally characterized to 1.46-Å resolution by X-ray diffraction. This crystal structure reveals a Lys residue hydrogen-bonded to PQQ at the site analogously occupied by a Lewis acidic cation in ADH. Accordingly, we prepared K142A- and K142D-PqqT variants to assess the relevance of this site toward metal binding. Isothermal titration calorimetry experiments and titrations monitored by UV-Vis absorption and emission spectroscopies support that K142D-PqqT binds tightly (Kd = 0.6 ± 0.2 μM) to La3+ in the presence of bound PQQ and produces spectral signatures consistent with those of ADH enzymes. These spectral signatures are not observed for WT- or K142A-variants or upon addition of Ca2+ to PQQ ⸦ K142D-PqqT. Addition of benzyl alcohol to La3+-bound PQQ ⸦ K142D-PqqT (but not Ca2+-bound PQQ ⸦ K142D-PqqT, or La3+-bound PQQ ⸦ WT-PqqT) produces spectroscopic changes associated with PQQ reduction, and chemical trapping experiments reveal the production of benzaldehyde, supporting ADH activity. By creating a metal binding site that mimics native ADH enzymes, we present a rare earth-dependent artificial metalloenzyme primed for future mechanistic, biocatalytic, and biosensing applications.

Evaluation of the use of polyvinyl alcohol in the manufacture of pressed samples for X-ray fluorescence analysis

The reliability of the results of X-ray fluorescence analysis (XRF), which is widely used in determination of the elemental composition of various materials, largely depends on the quality of sample preparation. When producing pressed tablets for X-ray fluorescence analysis of trace elements, a binder is often used in a powder form, which requires significant time for thorough homogenization. We present the results of applicating a polyvinyl alcohol solution as a binder in the manufacture of pressed samples without using a substrate in determination of microelements by XRF. The parameters for obtaining a durable tablet with a homogeneous composition that matches the condition of minimum impact on the intensity of the analytical lines of the elements being determined are presented. It is shown that the optimal sample weight for the proposed method of producing pressed tablets is 7 g with the addition of polyvinyl alcohol in a ratio of 7:1, the optimal drying time for the tablet after pressing is 1 hour. The calculated variation coefficients of the analytical signal (<2%) indicate the homogeneity of the produced tablets. The maximum values of standard deviations of pressed tablets for the selected ranges of elements are much less than acceptable, which confirms the validity of the proposed method of sample preparation. It is also shown that during long-term storage and repeated measurements, pressed tablets with the polyvinyl alcohol solution retain their original structure and intensity of analytical lines of elements. The accuracy of measurements in the subsequent determination of rock-forming elements is consistent with their certified contents. The results obtained can be used to reduce the time spent on getting a representative pressed sample when using polyvinyl alcohol, determining elements without additional support (coating films), microelement and silicate analyzes from one sample.

Interactions between rice starch and flavor components and their impact on flavor

Flavor is considered one of the most significant factors affecting food quality. However, it is often susceptible to environmental factors, so encapsulation is highly necessary to facilitate proper handling and processing. In this study, the structural changes in starch encapsulation and their effects on flavor retention were investigated using indica starch (RS) as a matrix to encapsulate three flavoring compounds, namely nonanoic acid, 1-octanol, and 2-pentylfuran. The rheological and textural results suggested that the inclusion of flavor compounds improved the intermolecular interactions between starch molecules, resulting in a significant increase in the physicochemical properties of starch gels in the order: nonanoic acid > 1-octanol > 2-pentylfuran. The XRD results confirmed the successful preparation of v-starch. Additionally, the inclusion complexes (ICs) were characterized using FT-IR, SEM, and DSC techniques. The results showed that v-starch formed complexes with Flavor molecules. The higher enthalpy of the complexes suggested that the addition of alcohols and acids could improve the intermolecular complexation between starch molecules. The retention rates of three flavor compounds in starch were determined using HS-GC, with the values of 51.7 %, 32.37 %, and 35.62 %. Overall, this study provides insights into novel approaches to enhance the quality and flavor retention, improve the storability and stability, reduce losses during processing and storage, and extend the shelf life of starchy products.

Reversible thermochromic K2O·nSiO2-based anti-fire glass with bidirectional responsion and memory function

We describe a low-cost method for the synthesis of reversible thermochromic K2O·nSiO2-based anti-fire materials with bidirectional responsion and memory function, which was significant for energy-saving and fire-resistant applications. Here, the reversible thermochromic (RTC) and inverted reversible thermochromic (IRTC) K2O·nSiO2-based anti-fire glass were prepared via an in-situ reaction using a high solid content and low viscosity SiO2 sol (HSLV SiO2 sol, 55 wt%). The morphological, thermochromic, thermal insulation, and memory performances were systematically characterized. The pincer-like structure, rod-like structure and the layered microporous morphology were clearly shown in scanning electron microscopy (SEM) micrographs. The color change, foaming, and memory mechanisms were further investigated in detail. The significant differences appeared in the visible region of RTC and IRTC K2O·nSiO2-based anti-fire glass during heating and cooling process. FTIR spectra were used to characterize the difference among RTC, IRTC and control samples. The results indicated that a small amount of NH4+ caused the K2O·nSiO2-based anti-fire glass to exhibit IRTC characteristics, and the continuous addition of polyhydric alcohols was the key to obtain RTC performance. The IRTC K2O·nSiO2-based anti-fire glass was suitable for the conservatories or greenhouses, and the RTC K2O·nSiO2-based anti-fire glass reduced the direct sunlight exposure to control the indoor temperature. Combined with morphological and Tg analysis, the thermal insulation performance was enhanced by a microporous insulating layer with a sponge-like structure. We also used the bidirectional reversible thermochromic performance to prepare a novel anti-fire glass component for construction with anti-counterfeiting function. This work provided a new approach for the application of multifunctional smart windows.

SURFACE PROPERTIES AND MICELLIZATION OF SODIUM ALKYLSULPHATES IN THE PRESENCE OF LOW-MOLECULAR ALCOHOLS

The process of micellization of sodium alkyl sulfates (SAS : sodium decyl- (SDS) and dodecylsulfate (SDDS)) of formation in aqueous solution without or with alcohols including propanol-1, propanol-2 and butanol-1 and their adsorption behavior at air-liquid interface were investigated with both the tensiometry and the conductometry at 298 K. The effect of chain length of alcohol on micellar and interfacial properties were discussed. Some parameters including surface excess concentration (Γmax), minimum area per surfactant molecule (Smin) at air-liquid interface, degree of ionization of micelle, and standard free energy of adsorption and micellization, etc. are estimated. It was experimentally established that the introduction of 0.5-1.0 mol/dm3 of alcohols into surfactant solutions contributes to the process of micellar formation of SAS and increases the stability of the micellar phase, as evidenced by the observed synergistic effect on the critical micelle concentration (CMC). The addition of different alcohols changes the values of Γmax, Smin, CMC of SDS and SDDS and induces an increase in degree of ionization (β) of micelle relative to that in pure water. When alcohols are introduced into SDS and SDDS solutions, the degree of ionization of micelles at a constant length of the alkyl radical of surfactant moderately increases with increasing alcohol content in the solution and ranges from 0.50-0.73 and 0.38-0.75, respectively. Also, the effect of alcohol was discussed. The obtained thermodynamic parameters were used to confirm these behaviors of interfacial adsorption or micellization. An increase in chain length of alcohol promotes the micellization process. The CMC values decrease with increasing length of the alkyl radical of alcohols. Propanol-1, compared to propanol-2, somewhat reduces the value of SDS and SDDS CMC to a greater extent. Standard free energy of micellization ∆G0mic, also confirms the micellization behavior. Standard free energy of adsorption (∆G0адс) indicates that an increase in the chain length of alcohol in aqueous solution is favorable to the adsorption of SDS and SDDS at air-liquid interface. A comparison of the values of the standard free energy of adsorption and micelle formation in sodium alkyl sulfates – alcohols – water systems showed that adsorption is the most thermodynamically advantageous process in the studies systems, and the packing of surfactant “molecules” in micelles is less dense, compared to packing in a mixed adsorption layer.

Tri(phenylethynyl)Bismuth: A promising and low-toxic pre-catalyst for stereoselective ring-opening polymerization of rac-lactide

Bismuth-based catalysts have gained attention for their low toxicity and remarkable catalytic activity in the production of biodegradable polyesters. This study introduces, for the first time, the synthesis and thorough characterization of tri (phenylethynyl) bismuth (BiAK3), achieved through 1H and 13C NMR and FTIR spectroscopic analysis. Subsequently, BiAK3 was employed in the ring-opening polymerization (ROP) of rac-lactide (rac-LA). Notably, the addition of alcohol as a co-catalyst facilitated polymerization via a coordination-insertion mechanism, yielding partially isotactic-enriched poly (lactide) (PLA) with a tacticity index of up to 0.67. The kinetic profile of this polymerization was explored through various experimental conditions, highlighting not only the catalyst's performance but also its remarkable control over the polymerization process. Significantly, a linear relationship between molecular weight (Mn) and LA conversion was observed, accompanied by narrow molecular weight distributions (Ɖ). Therefore, our findings highlight the potential of BiAK3 as a bismuth-based pre-catalyst for the control synthesis of biodegradable polyesters, shedding light on its catalytic efficacy and precision in controlling the polymerization.

High-Yield Synthesis of Hierarchical SAPO-34 by Recrystallization Method for Efficient Methanol-to-Olefin Reactions.

Prolonging the lifetime of SAPO-34 catalysts and enhancing their olefin selectivity in methanol-to-olefin (MTO) reactions are critical yet challenging objectives. Here, a series of hierarchical SAPO-34 catalysts were synthesized using a straightforward recrystallization method. The incorporation of triethylamine into the recrystallization mother liquor facilitated the formation of mesopores, achieving a high solid yield of up to 90%. Notably, the addition of phosphoric acid and ammonium polyvinyl phosphate alcohol during the recrystallization process significantly enhanced the crystallinity and regularity of the hierarchical SAPO-34 crystals, consequently increasing the mesopore size. Due to the substantially improved mass transfer efficiency and moderated acidity, the SP34-0.14P-0.06R catalysts exhibited a prolonged lifetime of 344 min and 80.3% selectivity for ethylene and propylene at a weight hourly space velocity (WHSV) of 2 h-1. This performance markedly surpasses that of the parent SP34 catalyst, which demonstrated a lifetime of 136 min and a selectivity of 78.0%. Remarkably, the SP34-0.14P-0.06R maintained a lifetime of 166 min even at a high WHSV of 10 h-1, which is more than 5-fold greater than that of the original microporous SP34. This research offers valuable insights into the design and development of hierarchically porous zeolites with high yields, enhancing the efficiency of MTO reactions and other applications.

Effect of intake valve lift and binary alcohol (bioethanol+isobutanol) addition on energy, exergy, sustainability, greenhouse gas impact and cost analysis in a hydrogen/diesel dual fuel engines

Greenhouse gas emissions are a significant problem contributing to global warming and climate change and it is essential to increase the use of renewable and biomass-derived fuels in internal combustion engines to reduce greenhouse gas formation. Alcohol fuels and hydrogen have become prominent in recent years due to less harmful emission levels as a result of combustion. While there are very few studies in the literature on ternary mixture + hydrogen in terms of energy and exergy, there is a gap on the effect of the valve lift amount. The aim of this study is to investigate the effects of binary alcohol addition and variable intake valve lift (IVL) in hydrogen-diesel dual fuel mode on energy, exergy, sustainability, and greenhouse gas emissions. The experiments are conducted at variable torque conditions, involving three different IVL values (4, 4.46, and 4.9 mm) and four different fuel combinations (diesel, diesel + H2, diesel + binary alcohol, and diesel + binary alcohol + H2). The binary alcohol addition consists of 10% bioethanol and 10% isobutanol volumetrically, while in the dual-fuel mode, hydrogen is injected into the cylinder at a constant flow rate. When the results are examined, the highest energy and exergy values are obtained with the IVL-Diesel + H2 operation, providing on average 11% and 8% higher exergy efficiency compared to IVL 4-Diesel and IVL 4.46-Diesel studies, respectively. Additionally, the exergy destruction in the IVL-Diesel + H2 study shows an average decrease of 16% and 12%, respectively, compared to the IVL 4-Diesel and IVL 4.46-Diesel studies. Additionally, significant reductions in emissions are achieved. In the IVL 4.9-EB20+H2 study, HC, CO, and CO2 emissions decrease by 28%, 40%, and 28%, respectively, compared to the IVL 4.0 study. When examining the GHG emission impact, it is analysed that operating a single-cylinder engine with EB20+H2 fuels under 4.9 mm IVL conditions emits, on average, 36% and 32% less GHG impact over a one-year period compared to IVL 4-Diesel and IVL 4.46-Diesel studies, respectively.

Organocatalyzed Asymmetric Conjugate Addition of Alcohols to β-Fluoroalkyl Vinylsulfones by Bifunctional Phosphonium Salt Catalyst.

Chiral secondary alcohols, serving as essential structural motifs, hold significant potential for diverse applications. The exploration of effective synthetic strategies toward these compounds is both attractive and challenging. Herein, we present an asymmetric oxa-Michael reaction involving aliphatic alcohols as nucleophiles and β-fluoroalkyl vinylsulfones catalyzed by bifunctional phosphonium salt (BPS), achieving high yields and excellent enantioselectivities (up to 98 % yield and 98 % ee). Additionally, a sequential process including asymmetric oxa-Michael and debenzylation, facilitated by BPS/Lewis acid cooperation, was revealed for synthesizing diverse chiral secondary alcohol compounds in high yields (81-88 %) with consistent stereoselectivities. Furthermore, mechanistic explorations and subsequent results unveiled that the enantioselectivity originates from hydrogen-bonding and ion-pair interactions between the BPS catalyst and the substrates.

Biodegradable Foam from Cassava Starch Blended with Water Hyacinth Fiber: Effects of Polyvinyl Alcohol Content

Abstract Our previous investigation revealed that the addition of water hyacinth fiber (WHF) and polyvinyl alcohol (PVA) enhanced the mechanical properties of cassava starch-based foam. However, the effect of PVA concentration on the mechanical properties of starch foam is still unclear. Therefore, this study examined the effects of various concentrations of PVA on the foam’s quality and production process. Four levels of PVA (0, 1, 2, and 3% w/w) were tested on the mixed dough of cassava starch and 15% of WHF. The foam was made by baking the dough on a thermopressing machine at a temperature of 190 °C for 3 min. The quality level of foams was determined by their physical and mechanical (compressibility, water adsorption, density, color appearance, and biodegradability) properties as well as the practicality of the dough preparation and baking processes. As a result, the addition of PVA significantly affects the mechanical properties and ease of making dough. A higher concentration of PVA contributed to a better mixture of the dough, resulting in a smoother mixing process that led to foams with stronger mechanical properties. Nevertheless, the application of 2% and 3% PVA did not make a significant difference in the mechanical and physical properties. Foam with 2% PVA showed 32 N/mm2 of compressibility, 10% water absorptivity, 12% water content, and good biodegradability, with 87% of the material lost during 30 days of burial in the soil.

Thermoformed products from high-density polyethylene and Softwood kraft pulp.

Plastic recycling, waste minimization such as process outfall valorization promotes a circular economy. Herein, food trays have been produced in the moulded pulp thermoforming process. To this end, high-density polyethylene (HDPE) outfall has been dispersed in water via Poly vinyl alcohol (PVA) addition in a Northern Bleached Softwood KraftPulp (NBSKP) slurry. Samples physical and mechanical properties have been evaluated. With an increasing HDPE content, parts air permeability was drastically reduced to a minimum of 2.4±0.8 mL min-1. In addition, water and grease hold out properties have been increased with minimum waterCobb1800 value of 10.9±5.4 gm-2 and oil Cobb1800 value of13.18±6.5 gm-2. Samples with high HDPE content demonstrated hydrophobic surface with water contact angle value above 90°. HDPE melting and binding to wood pulp fibers was monitored by SEM images. Regarding the mechanical properties, HDPE induced plastic deformation with a reduced Young modulus by 17 %. Moreover, the addition of HDPE increased wet strength by 81 %. However, the produced foodtray composites with high HDPE content demonstrated low repulpability index.

Stabilization of structure and channel height of two-dimensional montmorillonite membrane for efficient ion separation

As a new type of separation material, two-dimensional membrane has attracted wide attention due to its special transport mechanism. However, due to the hydration swelling of montmorillonite nanosheets, there are still challenges in preparing two-dimensional membrane with stable channel structure and fixed interlayer spacing. In order to overcome the problems caused by swelling, this study used polyvinyl alcohol and polyacrylic acid to stabilize the channel structure of two-dimensional membranes. Moreover, the crosslinking between Fe3+ and montmorillonite nanosheets was proposed to fix the interlayer spacing of two-dimensional membrane. It is found that various polymers had different effects on the mechanical property of two-dimensional membrane. The addition of polyvinyl alcohol and polyacrylic acid can significantly improve the tensile strength of the membrane. And the introduction of them reduces the hydrophilicity of the membrane surface, thus improving the stability of the membrane in water. In addition, the interlayer cations affect the stability of interlayer spacing of the membrane in water. After crosslinking the membrane with Fe3+, the interlayer spacing is fixed and can be maintained at about 0.94 nm in water for a long time. When a certain dosage of polyvinyl alcohol and PAA are added into the membrane and the crosslinking conditions are suitable, two-dimensional membrane has good selectivity to Li+ and Mg2+ in high Mg/Li ratio brine. Inspired by the natural ion exchange properties of montmorillonite, this study found a new method for inhibiting the hydration swelling of two-dimensional membrane and realizing precise control of interlayer spacing.

The Effect of Polyvinyl Alcohol Addition on the Optical Properties and Oxygen Detection Performance of Titanium Dioxide and Methylene Blue Nanocomposite Colorimetric Indicators.

In this study, we investigated the impact of polyvinyl alcohol (PVA) incorporation on the optical properties and oxygen detection performance of a titanium dioxide/methylene blue (TiO2/MB) nanocomposite colorimetric indicator for packaging applications. The nanocomposite was synthesized via mechanical milling of TiO2 nanoparticles with MB and citric acid. PVA, at varying concentrations (0, 3, 9, and 14 wt%), was introduced during the wet milling process to produce a homogeneous composite film. Spin coating was employed to fabricate TiO2/MB nanocomposite films for oxygen detection evaluation. The influence of PVA loading on the films' chemical functionalities and surface morphologies was assessed using Fourier-transform infrared spectroscopy (FTIR) and field-emission scanning electron microscopy (FE-SEM). The indicator's activation process, involving a color change between bleached and colored states, and its recovery time were monitored via optical imaging and UV-VIS-NIR spectrophotometry. The results revealed that a PVA content of 9 wt% yielded well-defined films with enhanced stability of the TiO2/MB nanocomposite's oxygen detection performance.

Fatty alcohols as sustainable compatibilizer agents for the compound of natural rubber/silica: The curing, rubberiness and tensile strength behaviours

Fatty alcohols are derived from palm oil production and, stearyl and lauryl alcohols are examples of them. The stearyl and lauryl alcohols have the potential to be used as rubber additives for the compounding and vulcanizing processes. These materials are relatively new as rubber additives and, they were added into silica-filled natural rubber (NR) compound. The aim of using them is to increase the grade of silica dispersion inside the NR matrix. Initially, the NR was filled by (precipitate) silica at 30 parts per hundred of NR, whilst the fatty alcohols were added into the silica-filled NR with variable concentrations from 1 to 4 phr, separately. The compounds of NR/silica/stearyl alcohol and NR/silica/lauryl alcohol have been vulcanised at 150 °C by implementing a semi-efficient rubber composition. From the vulcanization behaviour, it was observed that both fatty alcohols have the role of compatibilizer and plasticising agents for the compound of NR/silica. Those fatty alcohols decreased the viscousness but increased the curing rate index (CRI). The more concentration of fatty alcohols was supplied, the less viscousness and the higher the CRI. Those fatty alcohols also shifted the crosslinking level and tensile strength. It also observed that the break elongation or rubberiness has been shifted up. Tensile strength has been shifted to a maximal value with a 2 phr of stearyl alcohol or 3 phr of lauryl alcohol addition.