Papers by Keyword: Polyvinyl Alcohol

Abstract: Recent interests in hybrid polymers for fuel cell applications have given rise to the exploration, modification, and application of various polymer ionomers. Polymer membranes doped with suitable fillers have improved fuel cell performance compared to the pristine polymers. In this study, three ionomers, PAN, PVP, and PVA were synthesised idividually and then functionalised with zirconium phosphate nanoparticles as membrane nanofillers. The nanofibers were synthesised using the sol-gel polymerisation method from their respective precursors dissolved in either water or DMF solution. This was followed by their subsequent fabrication through the incorporation of the zirconium phosphate nanoparticles, which were synthesised from their precursor salt using the precipitation method. Techniques such as SEM, FTIR, TGA, and XRD were employed to characterise the physiochemical properties of the synthesised polymers. In addition, the electrochemical properties of the synthesised polymers were evaluated using CV and EIS. The obtained results showed that conductive nanofibers were successfully synthesized. As the scan rates increased under cyclic voltammetry, the reduction peak for PVP voltammograms disappeared, and the PAN exhibited an irreversible redox system. It is also noticeable that when scan speeds increase, the oxidation peaks for PAN voltammograms shift to higher potentials. On the other hand, the TGA results indicated that these nanoparticles had excellent thermal stabilities, making them suitable for use in fuel cell membranes under tough conditions. Based on these findings, PAN, PVA, and PVP polymer materials can be used as filler (dopant) materials for fuel cell membranes.

Abstract: Outdoor activities that are inevitable can harm our facial skin, namely, the signs of premature aging. A gel peel-off mask (GPM) is a popular facial skin care treatment that can alleviate these symptoms. This study investigated the influence of polyvinyl alcohol (PVA) and microcrystalline bacterial cellulose (MCBC) concentrations on the gel peel-off mask's features, including organoleptic properties, pH, viscosity, adhesion power, and drying time. The GPM formula contains carboxymethyl cellulose, glycerol, propylene glycol, PVA, and MCBC. The PVA content ranges from 7 to 15%, and the MCBC concentration ranges from 0 to 15%. Furthermore, a test was conducted to assess the potency of MCBC as a delivery agent for the active substance (vitamin C) from the product to the facial skin during skincare application. The experiment revealed that the best product was obtained at a PVA concentration of 13% and MCBC of 10%. Applying a 10% MCBC component can provide active vitamin C to the facial skin with an 85% efficacy. Additionally, respondents completed a product acceptability test. Based on the findings, the usage of MCBC components in gel peel or mask products has the potential to be a commercially viable product. However, research on GPM formula optimization is required for optimal use.

Abstract: Starch-based blend membranes is widely us in many application due to their biodegradability and low cost. Starch/Polyvinyl Alcohol/Eggsheell (Starch/PVA/EG) membranes were prepared with turmeric extract as a pH-responsive agent. Turmeric extract has good antioxidant activity and could act as a biosensor that changes color in different pH conditions. This research aims to study the effect of eggshells amount in the blend membranes on its thermal and pH-responsive properties. Starch/PVA/EG sheet was prepared by slip casting method. For pH responsiveness, the sheets were immersed into turmeric extract with 0,5 mg/mL in concentration for 24 hours and dried. Turmeric extract was analyzed using a spectrophotometer UV Visible to observe its response to pH and antioxidant activity. A pH-responsive sheet then analyzed the functional groups, thermal character, and the sheet's response in various pH conditions. A spectrophotometer UV Visible analysis shows that turmeric extract has shifted optimum peak in different pH conditions. An IC50 value of turmeric extract was 14.802 mg/L. Functional groups analysis showed that increasing eggshell addition had shifted peak of carbonyl groups at 1737 cm^-1 to 1627 cm^-1. Presence of CO₃^2- in Starch/PVA/EG sheets were confirmed by peak at 889.18 cm^-1. A DSC analysis results the highest thermal stability was obtained by 50% EG. All the starch/PVA/EG sheets gave response to pH change.

Abstract: Despite their widespread use due to affordability, ease of use, and corrosion resistance, polymers are susceptible to ultraviolet (UV) degradation. Recent advancements on UV-blocking technologies however, suffer from chemical incompatibility with organic polymer substrates such as polyvinyl alcohol (PVA). Thus, there is a need to explore sustainable and green alternatives for compatible UV-blocking materials. This study investigates the UV blocking performance of PVA reinforced with microcrystalline cellulose (MCC) extracted from used denim fabrics using mild acid hydrolysis. Optical microscopy and FTIR analysis of raw denim showed the structure of cotton fiber and the presence of indigo dye. MCC yield ranges from 43-83% with degree of polymerization (DP) of 146-173 after extraction at varying hydrochloric acid (HCl) concentrations. XRD and SEM analysis showed cellulose Type I structure and rod-shaped MCC with particle lengths of 37-78 μm. Increasing HCl concentration during hydrolysis led to shorter particle lengths and higher degree of crystallinity, indicating an increase in the crystalline phases due to conversion of cellulose to MCC. These results indicate the successful conversion of denim fabric to MCC. Lastly, the fabricated PVA-indigo MCC films were effective in blocking UV light while maintaining good transparency. When compared to bleached MCC, PVA with indigo MCC resulted to 12% more UV blocking. This can be attributed to the indigo retention and stability in MCC even after increased acid concentration, which is also shown in the FTIR and SEM analysis. These findings contribute to waste reduction efforts by utilizing cotton waste and offer a sustainable solution to produce UV-resistant PVA films.

Abstract: The following article represents the research on the elaboration of biodegradable films for environmentally friendly packaging based on polyvinyl alcohol, corn starch, glycerin, and borax. Growing consumption of packaging results in greater waste; the biggest part of which comprises problematic plastic packaging that is difficult and expensive to recycle. The majority of biodegradable packaging materials have insufficient technological characteristics. It is due to that the development of composite compositions based on inexpensive raw materials is a necessary condition to extend the range of high-quality safe packaging capable of minimizing environmental impact. The objective of the study is to obtain film materials based on polyvinyl alcohol, corn starch, and glycerin with the addition of sodium tetraborate and to study its mechanical and surface properties. The compositions for the film samples are prepared by an aqueous solution of Polyviol 6 04/140 polyvinyl alcohol to which water-soluble corn starch is added. The mixture is gelatinized, cooled, and glycerin and borax are added under stirring. Films are obtained by casting onto a glass substrate. The films obtained are almost transparent to the sight, soft and flexible by touch, showing good stretchability. The values of tensile strength for the films containing polyvinyl alcohol-starch, as measured by a dynamometer on a universal testing machine, are 1.5-1.7 times higher than that of samples without starch. The values for elongation at break of the films tested fall between 280 and 425%. Surface property testing of the obtained films is performed with an instrument for the determination of the wetting contact angle. Distilled water and ethylene glycol are used as test liquids for wetting. Wetting kinetics analysis of the films by water and ethylene glycol shows the possibility to make high-quality marking with necessary consumer information on them. Biodegradable films with a polyvinyl alcohol-starch mass ratio of 5:2 exhibit the best mechanical and surface properties. From a performance point of view, PVA, starch, and borax-containing films could be used as biodegradable packaging.

Abstract: Electrospinning technique is widely used to fabricate nanofibrous membranes mimicking the extracellular matrix structure. The utilization of synthetic polyvinyl alcohol (PVA) as the base material to construct electrospun nanofibers is often related to the limitation of biological function. Therefore, in this study, elastin (EL), a natural polymer, was incorporated into PVA matrix to overcome the biofunctional limitation. The ideal electrospinning parameters for the fabrication of PVA/EL electrospun nanofibers were investigated by varying the compositions of PVA/EL at 9.9/0.1, 9.5/0.5 and 9.0/1.0 (v/v) and the applied voltages at 18, 20 and 22 kV. With the increasing voltage from 18 to 22 kV, the mean fiber diameter decreased for the PVA and PVA/EL of 9.9/0.1 (v/v) while a fluctuating trend was observed for the 9.5/0.5 and 9.0/1.0 (v/v). The homogenous nanofibers construction with no beads was observed in the PVA/EL 9.5/0.5 (v/v). Both PVA and PVA/EL nanofibrous membranes displayed hydrophilicity with water contact angles below than 90°. In conclusion, the PVA/EL 9.5/0.5 (v/v) fabricated at 20 kV, possessed the ideal fiber morphology and wettability, to be subjected for biomedical applications.

Abstract: Transdermal patches find extensive application in both medicine and cosmetics, offering distinct functional properties based on their unique formulations. In this study, polymer film patches were developed using a mixture design methodology, incorporating polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), glycerol (GLY), and deionized water (DW). To investigate the impact of the mixture on patch viscosity, seventeen different mixtures were designed using extreme vertices and were prepared through a simple casting technique. The special quartic model proved to be the most suitable for explaining the relationship between ingredients and predicting viscosity, as it demonstrated impressive statistical performance with a standard deviation of 296.237, an R-squared value of 99.80%, and a mean absolute percentage error of 4.24%. To validate the accuracy of our viscosity predictions, five mixture ratios were randomly selected from the contour plots, resulting in a mean absolute percentage error of 7.71%. In evaluating viscosity and mixture ratio, PVA demonstrated a significant influence compared to other constituents. Higher levels of PVP correlated with increased viscosity, whereas increased GLY concentration led to decreased viscosity. Additionally, the impact of GLY on viscosity diminishes with higher concentrations of PVP and PVA, aligning with the antagonistic terms PVP*GLY and PVA*GLY. Furthermore, antagonistic behavior was observed for the PVA*DW interactions, while synergistic tendencies were observed for the PVA*PVP interaction.

Abstract: This study focused on the preparation of hydrogels of poly (vinyl alcohol) and cellulose extracted from hemp fibers with the aid of borax as a cross-linking agent. Cellulose extracted from hemp fibers was initially dissolved in a mixed solution of urea and NaOH to obtain a cellulose solution. In the meantime, PVA was also dissolved in the urea and NaOH. These two solutions were mixed, and various loadings of borax were introduced. Moreover, the effect of borax loadings on equilibrium water content (EWC) and compression properties of the cross-linked hydrogels was investigated. The cross-linked hydrogels showed an EWC of 95.76% and a compression set of 9.71%, compared to those of the physical cross-linked hydrogels which had an EWC of 92.40% and a compression set of 29.96%. It was found that the chemically crosslinked hydrogels exhibited greater stability compared with physical ones owing to the stronger interaction induced by borax. Therefore, The PVA/cellulose hydrogels cross-linked with borax hold potential in various applications such as wound dressing, wastewater treatment, and agricultural fields.

Abstract: Metal-Organic Frameworks (MOFs) have gained traction as an adsorbent due to their high surface area and porosity. MIL-101(Fe), a MOF that has been used for removing dyes in water by adsorption, faces the problem of being inseparable from water after use. To get around this difficulty, MIL-101(Fe) was incorporated into composite beads consisting of polymers Chitosan (CS), and Polyvinyl Alcohol (PVA) crosslinked with Glutaraldehyde (GLA) to remove Methyl Orange (MO) from water. The resulting CS/MIL-101(Fe)/PVA beads were optimized based on the right combination of synthesis parameters that gave the highest percent MO removal. It was found that the maximum MO removal can be achieved by beads made of 1500 ppm MIL-101(Fe), 2.0 % PVA, crosslinked in 2.5% GLA. Using FTIR analysis and SEM imaging, the beads exhibited favorable properties for adsorption, as shown by their coarse and porous structure. The beads proved viable for adsorption, exhibiting a percent MO removal of 69.62% upon validation.

Abstract: Hydrogels are polymers with soft and high-water absorption characteristics similar to biological tissues, leading to several potential applications, such as artificial organs, drug delivery, tissue engineering, and strain sensor. Interestingly, hydrogels can be designed to heal themselves after being damaged. In this research, hydrogels with self-healing ability from pectin and polyvinyl alcohol were prepared by simple physical mixing. Borax was used as a crosslinking agent to obtain crosslinked hydrogel structure by the formation of dynamic boron ester bonds. Glycerol was also added to the hydrogels as an anti-freezing agent and a stabilizer. The microstructures, mechanical properties, self-healing ability and swelling properties of the pectin/PVA-borax hydrogels were characterized. The results indicate that the size of microporous structure, modulus, tensile strength, self-healing time, swelling, and equilibrium water content of the pectin/PVA hydrogels increases with the increasing borax contents.