Mixture Of Polyvinyl Alcohol Research Articles

Dissolving Polymer Microneedles for Transdermal Delivery of Insulin.

It’s of great significance to develop insulin-loaded dissolving microneedles (MNs) which are fabricated with various methods and materials for transdermal delivery of insulin to effectively and efficiently treat diabetes. In this work, we present a kind of FITC-insulin tip-loaded dissolving MNs fabricated with the mixture of polyvinyl alcohol (PVA) and sucrose using homemade PDMS MNs mold under vacuum conditions. The uniform appearance of MN arrays contributes to controlling the drug dosage well as required. Sufficient mechanical strength for penetrating tough stratum corneum can be obtained by vacuum frozen-drying for at least 6 h after peeling MNs off the mold. About 90% of the FITC-insulin is localized in the conical MN tips and can be released into the skin within 2 min after insertion. The in vivo insulin absorption study and hypoglycemic effect in diabetic mice demonstrate that the proposed insulin-loaded MNs can efficiently deliver the insulin to the systemic circulation and exhibit a similar effect to hypodermic injection on hypoglycemic administration. Together these results suggested that the efficient MN fabrication process proposed in this work shows great potential for mass production and practical application of drug-loaded dissolving MNs in the future.

Optical Absorption and Photoconversion Characteristics of WO<sub>3</sub> Nanofiber Photoanodes Prepared by Electrospinning with Different Calcination Temperatures

This study aims to synthesize and examine the optical and photoelectrochemical properties of tungsten oxide (WO3) nanofibers prepared by electrospinning and calcination using different temperatures (500, 700, and 900 °C). The electrospinning solution contained a mixture of polyvinyl alcohol (PVA, 7.5% w/v) and ammonium metatungstate hydrate (AMH, 16.7% w/v). The morphology of WO3 nanofibers was observed via scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The absorbance of calcined WO3 nanofibers was measured, and the data was used to calculate the optical band gap energy (Eg) through Tauc’s relation. The of calcined WO3 nanofibers were found to be from 2.85 to 3.08 eV. The minimum value of was obtained from the sample calcined at 900 °C. Linear sweep voltammetry (LSV) was employed in the photocurrent measurements under simulated AM 1.5G at 100 mW/cm2 irradiance. The WO3 nanofiber photoanode calcined at 900 °C exhibited the maximum photoconversion efficiency (PCE) of 1.53%, a twice enhancement in PCE compared with those obtained from WO3 nanofibers calcined at lower temperatures. This study suggests the potential pathway for the optimal synthesis of high performance nanostructured metal oxide electrodes for photoelectrochemical water splitting.

Compatibility and stability studies involving polymers used in fused deposition modeling 3D printing of medicines

One of the challenges in developing three-dimensional printed medicines is related to their stability due to the manufacturing conditions involving high temperatures. This work proposed a new protocol for preformulation studies simulating thermal processing and aging of the printed medicines, tested regarding their morphology and thermal, crystallographic, and spectroscopic profiles. Generally, despite the strong drug-polymer interactions observed, the chemical stability of the model drugs was preserved under such conditions. In fact, in the metoprolol and Soluplus® composition, the drug's solubilization in the polymer produced a delay in the drug decomposition, suggesting a protective effect of the matrix. Paracetamol and polyvinyl alcohol mixture, in turn, showed unmistakable signs of thermal instability and chemical decomposition, in addition to physical changes. In the presented context, establishing protocols that simulate processing and storage conditions may be decisive for obtaining stable pharmaceutical dosage forms using three-dimensional printing technology.

Effect of composition of mono/di-hydroxy organic compounds and temperature on the aggregation behavior and physico-chemical properties of polyvinyl alcohol + TTAB mixture

Herein, the aggregation manners of polyvinyl alcohol (PVA) with tetradecyltrimethylammonium bromide (TTAB) in alcohols/diols media containing various concentrations and at several temperatures were performed using the conductivity measurement technique. Different physico-chemical parameters, such as critical micelle concentration (CMC), fraction of bound counter ions (β) and thermodynamic properties (ΔGo m, ΔHo m, ΔSo m, and ΔCo m) for the TTAB + PVA mixture in aqueous solutions of EtOH (EtOH), 1-propanol (1-PrOH), ethylene glycol (EG), and propylene glycol (PrG), have been determined. The CMC values were found to undergo a decrease in 1-PrOH in comparison to the values obtained in aqueous media, but in EtOH, the CMC value firstly decreases, touches the lowest point, and then exhibits an upsurge with further increase of the percentage of EtOH. The observed greater CMC values in diols media disclose that the micelle formation of TTAB + PVA mixture is delayed in the manifestation of diols. The CMC values of TTAB + PVA mixture have also been observed to vary with the change of study temperature. The negative values of ΔG0 m were obtained for all circumstances suggesting a spontaneous aggregation phenomenon of TTAB + PVA system. The values of ΔH 0 m and ΔS0 m dictate that the PVA molecule interacts exclusively with TTAB through the formation of hydrogen bonding, ion-dipole, and hydrophobic interaction. Furthermore, the standard molar heat capacity (ΔC 0 m), compensation temperature (T c), intrinsic enthalpy gain (ΔH 0,* m), and the thermodynamic properties of transfer (ΔG 0 m.tr, ΔH 0 m.tr. and ΔS 0 m.tr.) for the studied system were assessed and demonstrated with appropriate explanations.

Porous carbon nanospheres aerogel based molecularly imprinted polymer for efficient phenol adsorption and removal from wastewater

By adopting porous carbon nanospheres gel (PCNS-gel) carrier, the corresponding 3D monolithic surface molecularly imprinted polymer adsorbent ([email protected]) possesses unique advantages of excellent stability and efficient renewability besides its outstanding selectivity towards target phenol molecules. Carrier PCNS-gel is fabricated through the hydrothermal reaction of glucose, borax, and polyvinyl alcohol mixture. Based on the PCNS-gel, the functional adsorbent [email protected] is obtained via surface molecular imprinting technology, with phenol as template molecule and methacrylic acid as functional monomer. Owing to the surface imprinted layer, [email protected] performances a good adsorption capacity of 64.02 mg g−1 towards phenol. In addition, [email protected] has good selectivity towards phenol in the quaternary mixture solution of phenol, hydroquinone, p-nitrophenol, and p-tert-butylphenol with relative selectivity factors of 3.04, 16.50, and 3.93, respectively. More importantly, thanks to the 3D monolithic PCNS-gel carrier, the [email protected] adsorbent exhibits exceptional separation and recovery efficiency as well as outstanding stability and durability. The adsorption capacity only decreases by 10% after 10 repeated adsorption–desorption cycles. The adsorption capacity of [email protected] towards phenol in alkaline wastewater with complex composition is 58.4 mg g−1. The prepared novel 3D monolithic [email protected] adsorbent shows a promising application prospect for the deep and selective adsorption removal of phenol from wastewater.

Thermochemistry of Combustion in Polyvinyl Alcohol + Hydroxylammonium Nitrate

A mixture of polyvinyl alcohol (PVA) and hydroxylammoniun nitrate (HAN) forms a gummy solid known as a plastisol, which is ionically conducting. When an electrostatic potential of 200 V DC is applied across the plastisol, it ignites. Combustion ceases upon removal of the applied voltage. The products of PVA + HAN combustion are known to include the molecular gases carbon monoxide, carbon dioxide, water, nitrogen, and hydrogen. When the electric field within the plastisol is spatially uniform, combustion occurs preferentially at the anode. The fact that HAN is an ionic conductor suggests that the mechanism of combustion is electrolytic in origin. Consistent with the preference for combustion at the anode and the known gaseous products, we consider two reaction mechanisms. One involves atomic oxygen as the oxidizing agent at the anode and hydroxyl radical as the oxidizing agent at the cathode. The other involves ozone as the oxidizing agent at the anode and hydrogen peroxide as the oxidizing agent at the cathode. Each mechanism is applied to a scenario where the products are rich in the carbon oxides and to a second scenario where the products are poor in the carbon oxides. In the rich case, the heat of the overall reaction is −808.33 kJ per mole of HAN consumed and the electrical energy is converted to thermal energy with an efficiency of 4.2%. In the poor case, the corresponding figures are −567 kJ per mole of HAN and efficiency is 2.9%. The combustion reactions at the electrodes are uniformly exothermic with the exception of the reaction involving hydrogen peroxide at the cathode. When the products are poor in the carbon oxides, this reaction is actually endothermic.

Capability of core-sheath polyvinyl alcohol–polycaprolactone emulsion electrospun nanofibrous scaffolds in releasing strontium ranelate for bone regeneration

Core-sheath nanofibrous scaffolds from polyvinyl alcohol (PVA)–strontium ranelate (SrR)–Polycaprolactone (PCL) were prepared by water in oil electrospinning method. Thus, PCL (the oil phase) was used as the shell part and a mixture of PVA and SrR (the water phase) was inserted in the core. The amounts of SrR was varied from 0 to 15 wt.% Mussel-inspired dopamine-gelatin coating was done on the nanofibrous to improve their hydrophilicity and cellular attachment. The effect of the SrR content on morphology, mechanical, physicochemical, in vitro release behaviors, and biological properties as well as in vivo bone regeneration was investigated. Morphological observations revealed that continuous nanofibers with a core/shell structure were successfully obtained and the fibers diameter increased as the SrR content rose. X-ray diffraction (XRD) analysis revealed that SrR was molecularly distributed in the nanofibers and increasing the amount of the SrR decreased the crystallinity of the nanofibers. Moreover, the SrR release was regulated through the mechanism of Fickian diffusion and it was assumed as fast as possible in the samples with higher SrR content. The mesenchymal stem cell culturing showed improved cell proliferation by adding SrR and accelerating the expression of ALP, Runx2, Col I, and OCN genes. Besides, the SrR-loaded nanofibers improved bone formation of calvarial defects in a rat model as revealed by in vivo investigations.

Effect of polypropylene and polyvinyl alcohol fibers on characteristics and microstructure of polymer composite

AbstractThis study aims to assess the mechanical properties of polymer composite (PC) reinforced by introducing two types of synthetic fibers including polypropylene (PP) and polyvinyl alcohol (PVA). The optimum amount of resin was evaluated through mechanical tests. Then, selected fibers were added to the optimum mix in three fractions (0.5%, 1%, and 1.5%) by the weight of the binder. Various properties of PC which are density, compressive strength, flexural strength, modulus of elastic, and water absorption were appraised for all mix combinations after different curing times (1, 3, 7, and 28 days) beside scanning electron microscopy analysis for microstructure observation. Experimental outcomes revealed that by rising the PP fiber content, the mechanical strengths of fiber‐reinforced polymer composite (FRPC) were ameliorated, where compressive and flexural strength grew 58.14% and 78.31%, respectively, at the highest fiber ratio (1.5%) compared with the plain PC. On the other hand, PC reinforced by PVA fibers represented an inverse behavior that by ascending the fiber fraction, reduction in the properties of FRPC observed. Therefore, the fiber content obtained better performance was 1.5% and 0.5% for PP and PVA mixtures in PC, respectively.

Endovascular Management of Auricular Arteriovenous Malformations

This is a retrospective review of eight patients with extracranial arteriovenous malformations (AVMs) of the auricular region. All cases presented with significant hemorrhages or cosmetic defects. Highflow AVMs of the auricular are quite rare in contrast to low flow vascular lesions of the head and neck, making early diagnosis and treatment critical as incidences of recurrence are high if not managed properly. The purpose of this study is to present our experience of experimental endovascular treatment in a series of eight patients with auricular AVMs. From January 2015 to December 2017, eight patients with auricular AVM were put through transcatheter arterial embolization and percutaneous direct puncture embolization with polyvinyl alcohol (PVA) and bleomycin in five patients, glue embolization in one patient and coiling along with PVA in two patients to occlude high-flow fistula. Clinical outcomes were obtained through physical examination, and symptoms and a degree of devascularization on follow-up angiography. We performed 10 therapeutic embolization procedures. Of these, 3 resulted in absolute devascularization while 5 resulted in 75% obstruction. In 5 patient's embolization was performed as a palliative procedure. The other 3 were embolized as a sole mean of treatment for occluding the AVM. Only two patients developed postembolization necrosis and infection, and there has been no reexpansion of lesions to date. While thus far only having been used as percutaneous local sclerotherapy, this study found that bleomycin and PVA mixture, if used intraarterially can be more effective in the management of auricular AVM's.

The initial study of polyvinyl alcohol/honey/glycerin composite fibers

Abstract In this report, composite fibers were synthesized from PVA (polyvinyl alcohol) as the primary polymer backbone, added with glycerin as a plasticizer and honey using the electrospinning method. The precursor solution consisted of a mixture of PVA and honey solutions, each at 10 wt% in water, and glycerin. The composition of the mixture was as follows; ten grams of PVA solution was firstly mixed with 0.5 g of a honey solution until it became completely homogenous. The glycerin was later added at varying masses to the PVA-honey solution. The masses of the glycerin added were 0, 50, 100, 150, 200, 250, and 300 g. For each sample, the precursor solutions were characterized by their surface tension, viscosity, and conductivity. Afterward, the final solution was inserted into a syringe and then fed at 5 μl.min−1 to the applied voltage of 15 kV for the electrospinning to proceed. The result of the electrospinning shows that the diameter of the fibers increased as the content of glycerin increased. The average fiber diameter of composite fiber decreased along with the increasing applied voltage from 12 to 15 kV. However, the average diameter reduced when the applied voltage increased afterward. The swelling degree experiment was then conducted to investigate the effect of glycerin on the fibers. Glycerin appears to hinder the swelling of fibers when immersed in a phosphate buffer solution (PBS) liquid. The presence of glycerin and honey is confirmed by the appearance of their characteristic peaks in the Fourier transform infrared (FTIR) spectra of the composite fibers.

Development of Silica Nanoparticles Based Nontoxic, Transparent SUPER Hydrophobic Coatings

Research work on the advancement of super hydrophobic surfaces exhibits promising applications. Among them, one of the major applications is to make the surfaces more corrosion-resistant in order to enhance the long-term chemical and mechanical stability and durability of the surface. Current research work is focused on the development of transparent, corrosion resistant and modified Super Hydrophobic Coatings. The coated samples were prepared and the contact angles of water droplets on the surface were measured to check their wettability. Moreover, the self-cleaning properties of these super hydrophobic surfaces fabricated by various methods and their chemical and mechanical stability was investigated. Transparent Superhydrophobic coatings were developed by using Silica Nanoparticles and Polyvinyl alcohol(Polymer). Silica Nanoparticles were first synthesized by Stober process and then were functionalized to create surface roughness on them by using a coupling agent "Trichloro(methyl)silane". The modified Silica Nanoparticles were then associated with a mixture of PVA and MEK (methyl-ethyl ketone). Durability and hydrophobicity of the developed coatings on different surfaces were examined. The mean contact angle between the coated surface and water droplets was measured to be more than 170o. Samples that were associated with PVA (polyvinyl alcohol) shows the best results for super hydrophobicity and durability of the coating. The potential of the functionalization sparks the idea of possible functionalization of silica nanoparticles using other polymers. Keyword : Hydrophobic, Self-cleaning, Wettability, Transparent, Contact Angle, SiNPs, Silica Nanopartciles Figure 1

Visual determination of oxidation of edible oil by a nanofiber mat prepared from polyvinyl alcohol and Schiff's reagent.

A fiber mat was developed to visually determine the oxidation of edible oils, based on the colorimetric reaction of Schiff's reagent and aldehydes - the major volatile formed during lipid oxidation. The mixtures of polyvinyl alcohol (PVA) and Schiff's reagent containing various amounts of glycerol were electrospun to form the fiber mats. The response of the PVA/Schiff's reagent fiber mats to gaseous hexanal (model aldehyde) was investigated. Oxidized soybean oils were used to evaluate the effectiveness of the PVA/Schiff's reagent fiber mat for indicating oxidation of the oils. The results showed that the fiber mats obtained had average fiber diameters of less than 100nm. Upon hexanal exposure, the fiber mats turned from white to purple. Higher amount of glycerol led to larger color change of the fiber mats and shorter response time to hexanal. A linear relationship (R2 = 0.96) was observed between the color change of the mat and hexanal concentration (15-117μmolL-1). The visual determination limit of the mat for hexanal was 29μmolL-1. The color change of the PVA/Schiff's reagent fiber mat was increased with an increase of soybean oil oxidation. Out of the seven soybean oils tested, the PVA/Schiff's reagent fiber mat was able to correctly indicate the oxidation states of six oils. The result suggested that the visual determination method developed is a promising method to indicate the oxidation of edible oils, which can be performed easily by non-experts.Graphical abstract.

Film production with flaxseed mucilage and polyvinyl alcohol mixtures and evaluation of their properties.

Flaxseed mucilage was extracted with distilled water, dried and used for film production with polyvinyl alcohol (PVA) (ratio 1:1) of different hydrolysis degrees (88.0 and 98.3%). The properties of the films were evaluated by determining the thickness, tensile measurements, moisture content, water vapor permeability, apparent opacity, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) analysis and thermogravimetric analysis. Flaxseed mucilage, when mixed with PVA, produces less resistant, less rigid, more-flexible films, has a higher thermal stability, and does not change the water vapor barrier properties compared with pure mucilage films. SEM revealed that films with mucilage and PVA mixtures formed a compact and homogeneous structure, corroborating the FTIR spectra that indicated a chemical interaction between these two biopolymers. In general, the degree of PVA hydrolysis did not influence the properties of the films when mixed with flaxseed mucilage extract. Therefore, films obtained from mixtures of flaxseed mucilage and PVA can be an interesting and advantageous alternative for producing bio-based packaging.

Fabrication of PbSO4 negative electrode of lead-acid battery with high performance

This paper reports the preparation and electrochemical properties of the PbSO4 negative electrode with polyvinyl alcohol (PVA) and sodium polystyrene sulfonate (PSS) as the binders. The results show that the mixture of PVA and PSS added to the PbSO4 electrode can significantly improve the specific discharge capacity of the PbSO4 electrode, which reaches 110 mAh g−1 and survives 700 cycles at full charge and discharge at 100 mA g−1. The mixture of PVA and PSS can also replace the short fibers used in conventional cells, and shortens the activation time of the electrode.

Fabrication of Oregano-Olive Oil Loaded PVA/Chitosan Nanoparticles via Electrospraying Method

ABSTRACT Recently, a large number of studies on new methods has\\been carried out to increase the antimicrobial activity of bioactive compounds in essential oils. One of the most effective ways is to encapsulate them within some polymer matrix for preservation and extending their bioactive properties. This study appears to be the first attempt to fabricate oregano-olive oil-loaded nanoparticles for increasing bioactive properties. In this study, mixtures of polyvinyl alcohol (PVA) and chitosan were electrosprayed to obtain polymeric nanoparticles in which a mixture of oregano-olive oil was encapsulated. The electrospraying parameters were optimized under static conditions. The fabricated nanoparticles were characterized in terms of their molecular, thermal, and bioactive properties. Antifungal activity of the nanoparticles was tested against some fungal pathogens; Colletotrichum gloeosporioides, Botrytis cinerea, Penicillium chrysogenum. Antioxidant activity of the olive oil, oregano essential oil, and oil-loaded nanoparticles was determined according to 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging method. The results of this study indicated that oil-loaded nanoparticles have a potential to be used as an antimicrobial agent in food preservation applications.

Phase equilibria and structures of phases in the chitosan—polyvinyl alcohol systems

Phase equilibria in the mixtures of polyvinyl alcohol (PVA) and chitosan were revealed. Structures of the phases were identified. The temperature and concentration dependences for the chitosan—PVA and chitosan—PVA—water systems were determined. The phase state diagram was built. It is shown that the polymer mixtures are characterized by a complex supramolecular organization, which corresponds to their phase diagram.

Поливинил спирті мен крахмал негізіндегі гидрофильді қоспалардың жылу оқшаулағыш материалдардың физика-механикалық қасиеттеріне әсері

Thermal insulating materials based on diatomite with burnable and reinforcing additives modified with synthetic and natural polymers have been developed. A mixture of polyvinyl alcohol and starch was used as modifying polymers. The parameters of linear shrinkage, density, tensile strengths in compression and bending, as well as the coefficient of thermal conductivity of the material were determined depending on the concentration and ratio of polymers. It was established that polymer additives had a positive effect on almost all specified characteristics of thermal insulating materials. For example, when adding polymers up to 1 mass.%, the linear shrinkage coefficients decrease from 14.5 to 4.5%, the ultimate compression strengths increase from 0.22 to 2.51 MPa, the ultimate bending strengths increase from 0.2 to 1.26 MPa, the coefficients of thermal conductivity decrease from 0.068 to 0.049 W/m∙K. The densities of materials are in the range of 0.592-0.491 g/cm3. The results of the work showed that the obtained heat-insulating materials can be used as plasticizers in the field of thermal energy.

Technology of Orodispersible Polymer Films with Micronized Loratadine-Influence of Different Drug Loadings on Film Properties.

The production of orodispersible films (ODFs) with suspended insoluble drug substances is still a challenge, mainly due to the difficulty associated with achieving a proper homogeneity and mechanical properties of the films. Hypromellose (HPMC) and a mixture of polyvinyl alcohol (AP) and povidone (PVP) were compared in terms of their suitability for ODFs incorporating suspended micronized loratadine (LO) in a concentration range of 10%–40%. In a planetary mixer (Thinky), a uniform dispersion of LO in an aqueous viscous casting solution was obtained. The suspended LO particles caused dose-dependent changes in the viscosity of the casting mass and affected the mechanical quality of ODFs. Drug concentrations higher than 30% reduced the film flexibility and tear resistance, depending on the polymer type. LO films with a thickness of 100 µm disintegrated within 60-100 s, with no significant influence of the LO content in the range 10%–30%. HPMC films, regardless of the drug concentration, met the pharmacopoeial requirements regarding the uniformity of the drug content. AP/PVP films were too elastic, and the drug content uniformity was not achieved. The conclusion is that, using an HPMC matrix, it is possible to obtain a high load of a poorly water-soluble drug (30% of dry film mass corresponds to a dose of 5 mg per 1.5 cm2) in ODFs characterized by proper physical characteristics.

Properties of native and blended oil palm starch with nano-silicon dioxide as binder for particleboard

The replacement of the synthetic binder like urea formaldehyde and other suitable binder with natural adhesive like starch is very challenging to meet acceptable properties. This study evaluates the physicochemical and properties of both native starch and blended oil palm starch from the mixture of polyvinyl alcohol, boric acid and nano silicon dioxide. The result shows higher crystalline index and enthalpy peak of differentiate scanning calorimetry from blended oil palm starch bonded particleboard in comparison with those bonded with native starch. Morphological changes of native starch after blending process were observed from the scanning electron micrograph. Improvement were seen in both the dimensional stability and internal bond strength. The study shows that blended oil palm starch would be a potential candidate as a green binder in particleboard production.

Comparative Study of Polymer Nanoparticles on the Basis of Caprolactone–Polyvinyl Alcohol Mixtures with an Encapsulated Antitumor Preparation by Atomic Force Microscopy, X-Ray Diffraction, and Dynamic Light Scattering

The morphology, structure, and optical properties of composites with biodegradable polymeric particles, which are based on poly-e-caprolactone–polyvinyl alcohol (stabilizer) mixtures and contain 5-Fluorouracil (an antitumor preparation), have been studied by atomic-force and optical microscopy, X-ray diffraction, and dynamic and static light scattering. Studies have shown that the morphology of synthesized composites sustains appreciable transformations depending on their stabilizer content. No crystalline reflections corresponding to 5-Fluorouracil have been revealed, thus arguing for a high dispersity of this preparation in the polymeric matrix of caprolactone. The correlations between the structural and morphological parameters, composition, stabilizer concentration and the efficiency of the encapsulation of 5-Fluorouracil by the composites have been established.