Pure PVA Research Articles

Green and renewable thermoplastic polyvinyl alcohol/starch blend film fabricated by melt processing

In this study, the PVA/starch blend films were prepared by dry melting method. The microstructure showed that the starch existed in the continuous PVA matrix in granular structure. When the amount of starch was 30 wt%, the tensile strength increased from 12.8 to 14.7 MPa, and the elastic modulus increased from 15.4 to 20.5 MPa, and the water absorption increased by about 2 %. The addition of starch increased the Tmax by 8.1–29.64 °C compared to pure PVA. Considering the mechanical, hydrophilic and optical properties of the blend films, PVA/starch at 7:3 was the most promising packaging material. Notably, the blend films exhibit great reusability and renewability. Overall, these findings highlight the potential of PVA/starch blend films as environmentally friendly materials with enhanced properties.

Evaluating Optical Properties of Mixed-Phase 2D MoSe2/Poly(vinyl alcohol) Nanocomposite Film.

Highly solar light-absorbing poly(vinyl alcohol) (PVA) nanocomposite films have garnered wide attention in fields such as flexible optoelectronics, solar energy harvesting, and photothermal therapy. However, fabricating PVA nanocomposite films with a broad spectrum of solar absorption using cost-effective and non-toxic nanofillers remains challenging. Herein, nanocomposite films of PVA incorporating various concentrations of mixed-phase 2D MoSe2 nanosheets (i.e., a combination of the 2H and 1T phase) were prepared using a solution casting technique. Scanning electron microscopy (SEM) shows homogenous dispersion of MoSe2 nanosheets in the PVA matrix even at higher concentrations, while atomic force microscopy (AFM) reveals increasing surface roughness with increasing MoSe2 content, reaching a plateau after 20 wt%. With the increase in the concentration of MoSe2, the nanocomposite films exhibit interesting light absorption characteristics reaching their highest absorption (average 94.9%) at 40 wt% MoSe2. The incorporated mixed-phase MoSe2 nanosheets induce a significant change in the energy levels of the PVA matrix, which is reflected in the reduced optical band gap energy (2.63 eV) at 40 wt% MoSe2 against pure PVA (5.28 eV). The excellent light absorption of PVA nanocomposite films across the entire range from 250 nm to 2500 nm is attributed to the thin 2D structure of MoSe2 and the presence of its mixed phase.

Facile fabrication of carbon nanotubes/zinc oxide decorated poly(vinyl alcohol) electrospun nanofiber membrane and its photocatalytic performance

AbstractThe carbon nanotubes/zinc oxide (CNTs/ZnO) nanocomposites were immobilized on the poly(vinyl alcohol) (PVA) membrane for highly reutilization rate in photocatalytic degradation of RhodamineB (RhB) based on the combination of electrospinning and ultrasonication treatment. The results revealed that the CNTs are successfully compounded with ZnO, and the surface of nanofibers was uniformly covered with CNTs/ZnO nanoparticles. Under visible light irradiation, the CNTs/ZnO@PVA nanocomposites displayed excellent photocatalytic activity with 98.4% of RhB degradation rate within 3 h illumination. In comparison with pure PVA, and CNTs/ZnO with equivalent loading capacity on CNTs/ZnO@PVA film suspended in aqueous solution, the synthesized CNTs/ZnO@PVA film degrades RhB dye more efficiently. Furthermore, the photocatalytic activity of CNTs/ZnO@PVA nanocomposites did not change significantly even after five recycles, indicating a certain degree of reusability. The mechanism of enhanced photocatalytic activity was proposed. The as‐prepared flexible CNTs/ZnO@PVA nanocomposites could be employed as a promising material for the practical photocatalytic degradation of wastewater.

Green plastics: Direct production from grocery wastes to bioplastics and structural characterization by using synchrotron FTIR

Lignocellulosic bioplastics were produced using four different green wastes: hemp, parsley stem, pineapple leaves and walnut shell. Two different solutions were used to dissolve the green wastes: trifluoroacetic acid (TFA) and pure water. The changes in their natural structures and the solvent effect during the regeneration in biofilm formation were investigated by using Synchrotron FTIR Microspectroscopy (SR-µFTIR). The presence of cellulose, hemicellulose and lignin components in the water-based biofilms was confirmed. After dissolving in TFA, the spectra demonstrated some additional bands especially in the hemicellulose region. This is due to the hydrolysis of ester bonds and conversion to carboxylic acids. Principal component analysis showed grouping due to different solvents and polymer addition. Hemp-PVA (Polyvinyl Alcohol) composite biofilms were obtained by adding polyvinyl alcohol to the hemp solution to give extra strength to the hemp biofilms. It has been shown that water-based hemp-PVA biofilms do not cause any significant spectral changes, comparing with pure hemp and PVA spectra. However, after dissolving in TFA, unlike water-based biofilms, it appears that TFA molecules are retained by PVA through hydrogen bonds of TFA’s carboxylic acid and hydroxyl groups and distinct spectral regions belong to TFA bands are clearly identified.

Recent Advances in Poly(vinyl alcohol)-Based Hydrogels.

Poly(vinyl alcohol) (PVA) is a versatile synthetic polymer, used for the design of hydrogels, porous membranes and films. Its solubility in water, film- and hydrogel-forming capabilities, non-toxicity, crystallinity and excellent mechanical properties, chemical inertness and stability towards biological fluids, superior oxygen and gas barrier properties, good printability and availability (relatively low production cost) are the main aspects that make PVA suitable for a variety of applications, from biomedical and pharmaceutical uses to sensing devices, packaging materials or wastewater treatment. However, pure PVA materials present low stability in water, limited flexibility and poor biocompatibility and biodegradability, which restrict its use alone in various applications. PVA mixed with other synthetic polymers or biomolecules (polysaccharides, proteins, peptides, amino acids etc.), as well as with inorganic/organic compounds, generates a wide variety of materials in which PVA's shortcomings are considerably improved, and new functionalities are obtained. Also, PVA's chemical transformation brings new features and opens the door for new and unexpected uses. The present review is focused on recent advances in PVA-based hydrogels.

An experimental study on jute/banana fiber reinforced poly(vinyl alcohol) composites with nanofiller

AbstractThe incorporation of nanoparticles into natural fiber composites has the potential to alter the characteristics of natural fiber composites. In this study, various properties of jute and banana fiber reinforced poly(vinyl alcohol) (PVA) composites with different nanofillers incorporation were investigated. Samples were prepared using the vacuum bagging technique. Inorganic nanoparticles (Al2O3, ZnO, MgO, CuO, and TiO2) were synthesized using a ball milling machine and in each sample, 3 wt.% of nanofillers were incorporated. The maximum ultimate tensile strength and elongation percentage is found for TiO2, which is 90.433% higher than pure PVA whereas MgO incorporated samples provides maximum flexural strength, which is 162.59% higher than PVA. The sample with Al2O3 provides strongest impact resistance, 17.3 J/cm2. It was found that the decomposition temperatures were slightly higher for MgO and CuO doping than the undoped PVA composite. The FT‐IR spectra exhibited notable hydroxyl groups and minor shifts indicating a reduction in hydrophilicity upon the introduction of nanoparticles. The water absorption exhibited a reduction of up to 36% in conjunction with an increase in density across all samples. The highest crystallinity is found for CuO nanofiller composite, validated by x‐ray diffraction analysis. Additionally, morphological changes in the composites were seen through scanning electron microscopy and EDX shows a strong peak at 2.1 keV indicate some impurities present in the samples.Highlights Jute/banana/PVA composites were prepared with 3 wt% nanoparticles incorporation. Metal oxides such as Al2O3, ZnO, MgO, CuO, and TiO2 were used as nanoparticle. The use of nanoparticle improved the tensile, flexural, and impact properties. Decomposition temperatures were found higher for MgO and CuO incorporated composites. Upon nanoparticle incorporation, water absorption exhibited a reduction of upto 36%.

Development of biocompatible packaging material: starch/PVA-based bio-composite enhanced with hydroxypropyl methylcellulose

ABSTRACT Hydroxypropyl methylcellulose (HPMC) incorporated bio-composite films (unplasticized and plasticized) were prepared from pregelatinized maize starch/polyvinyl alcohol (PMS/PVA) blends by solution casting method. 10% boric acid (BA) was used as crosslinker. The physico-mechanical properties (tensile strength (TS), elongation at break (%EB), water solubility and moisture uptake) of the bio-composite films were studied. The thermo-chemical stability of the biofilms was studied by FT-IR, TGA and DSC analysis. TS, %EB, water solubility and moisture absorbency of 10% HPMC containing unplasticized films were found 38.1 MPa, 8.5%, 61% and 32.3%, respectively, however, the films were hard and brittle. On the contrary, TS, %EB, water solubility and moisture absorbency of 10% HPMC plasticized films were found 19.2 MPa, 28.5%, 62.2% and 57.3%. The biofilms exhibited relatively low water solubility and moisture uptake compared to higher HPMC containing composite. The thermo-chemical analysis revealed that the HPMC incorporated plasticized film was more thermally stable compared to pure PMS, PVA, HPMC and other bio composite films due to strong hydrogen bonding interaction with BA. The biodegradability of HPMC incorporated plasticized films was confirmed by soil burial test (anaerobic condition, RH 98%, 3 months). Therefore, the plasticized biofilm would be considered an alternative approach for biocompatible packaging material.

Physical Adsorption of Polyacrylic Acid on Boron Nitride Nanotube Surface and Enhanced Thermal Conductivity of Poly(vinyl alcohol) Composites.

To fully tap into the potential of boron nitride nanotubes (BNNTs), addressing their inherent insolubility was imperative. In this study, a water-soluble polymer, poly(acrylic acid) (PAA), was employed as a surface-active reagent, using an accessible and scalable approach. The physical properties and structure of PAA-BNNT were meticulously confirmed through valuable characterization techniques, encompassing X-ray diffraction, scanning electron microscopy, Fourier-transform infrared, X-ray photoelectron spectroscopy, and thermogravimetric analysis. PAA-BNNT exhibited remarkable dispersion in water and demonstrated compatibility with the poly(vinyl alcohol) (PVA) matrix. When incorporating 30 wt % of PAA-BNNT (about 24.75 wt % net BNNT) into the PVA matrix, the thermal conductivity surged by over 21.7 times compared to pure PVA due to the uniform dispersion of high-concentration PAA-BNNT in the polymer matrix.

A demethylated lignin improved PVA-based supramolecular plastic with tough, degradable, and water-resistant performances

Poly (vinyl alcohol) (PVA), as an excellent degradable plastic feedstock, is limited by its diminishing stability in wet environment, low strength, thermal instability and nonopaque properties. In response to these concerns, a PVA/demethylated lignin-based supramolecular plastic (DPVA-HA-Fe-5) was designed and produced from PVA, demethylated lignin (DL), humic acid (HA) and Fe3+ ions via a simple casting method. As compared with pure PVA plastic, the tensile strength of DPVA-HA-Fe-5 were increased by 411 % to 410.61 MPa, and the breaking strain was increased by 149 % to 239.47 %. Notably, the hydrophobicity of DPVA-HA-Fe-5 was also significantly improved. Although in highly humid environment (stored in RH = 100 % for 10 days) or in alkaline organic solvent (stored in pyridine for 3 h), DPVA-HA-Fe-5 also showed excellent mechanical strengths of 302.9 and 222.99 MPa, respectively, which are equivalent or even superior to the most of commercial petroleum-based plastics. Moreover, the prepared plastics showed an outstanding UV resistance and shading performance, and about 98.3 % protection against ultraviolet radiation B rays and 90.7 % protection against visible light were obtained. In short, the introduction of lignin to improve the performance of PVA-based plastic is a feasible method, and it could facilitate the development of high-value utilization of lignin.

Adsorption behaviors and mechanisms of porous polyvinyl alcohol/xanthan gum hydrogel for methylene blue and Pb2+

Faced with extensive water pollution caused by dyes and heavy metals, it is imperative to create cost-effective adsorbents that can effectively eliminate residual pollutants in wastewater. The synthesis of polyvinyl alcohol/xanthan gum (PVA/XG) hydrogels involved a combination of freeze-thaw cycling technique and the adsorption characteristics and mechanisms of methylene blue (MB) and heavy metal ions Pb2+ were investigated. In comparison to pure PVA hydrogels, the swelling behavior of PVA/XG3 hydrogel exhibited a 185 % increase in swelling rate. The adsorption test results suggested that PVA/XG3 hydrogel was effective in absorbing MB (27.39 mg/g) and Pb2+ (17.07 mg/g) from a 50 mg/L pollutant solution. The adsorption process of MB and Pb2+ by PVA/XG3 hydrogel followed Langmuir adsorption isotherm and the QFO models, indicating a preference for homogeneous physical adsorption. Specifically, the Langmuir isothermal model predicted that the qmax of MB and Pb2+ by PVA/XG3 hydrogel were 94.47 and 58.50 mg/g, respectively. Therefore, this essay has created a cost-effective and environmentally friendly method for producing versatile PVA/XG hydrogels specifically intended for water treatment purposes.

INTEGRATED EMULSION PAINTS DERIVED FROM THREE POLYVINYL ACETATE (PVA) GROUNDNUT OIL

A modified paint was produced in this research to supplement and substituteproducts by tender small-scale private paint factories, in an era of increasing demand of paints by the nation’s alarmingly growing building technology. The research was aimed at the formulation of an emulsion paint with the aid of polyvinyl acetate mixed with Groundnut oil as a binder by reducing volatile organic compounds and to determine the major physical parameters such as drying time, period of elongation, density, refractive index, adhesion, pH, and chemical resistance. The result obtained showed increase of dry to hard from Pure PVA paint (90.23 minutes) followed by Gombe PVA paint (105.5 minutes) to Taraba PVA paint (110.00 minutes). The drying time of the paint samples was in this order Taraba PVA paint (80.0 min) > Gombe PVA paint (75.5 min) > Pure PVA paint (75.23 min). The dry to touch was in the decreasing order: Taraba PVA paint (56.2 min) > Gombe PVA paint (53.4 min) > Pure PVA oil (49.15 min). The density (g/cm3) showed that Gombe PVA paint (1.16) > Pure PVA paint (1.30) > Taraba PVA paint (1.10). The solubility test for both Taraba PVA Groundnut paint and Gombe PVA Groundnut derived paint are practically insoluble in water, while Pure PVA derive paint dissolved in water instantly. All the three formulated paints passed the resistance blistering and flexibility tests. FTIR showed the following functional groups Hydroxyl, Amines, Carboxylic acids, Alkylhallides, Ketones and Aldehydes at specific wavelength are present in paints that serves as...

Rice straw-based cellulose nanofiber reinforcing polyvinyl alcohol antibacterial film through electrospinning

TEMPO-cellulose nanofibers (T-CNF) were prepared from rice straw through 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidation method. Subsequently, T-CNF reinforced polyvinyl alcohol fiber films (T-CNF/PVA) were fabricated by electrospinning. SEM images revealed that the introduction of T-CNF into PVA resulted in a slight decrease in fiber diameter within the T-CNF/PVA films. The tensile strength and elastic modulus of the T-CNF/PVA-2 fiber film were 44.59 MPa and 20.75 MPa, respectively, with T-CNF content of 1.64 wt%. The tensile strength of T-CNF/PVA-2 being approximately 9 times greater than that of pure PVA fiber film. Molecular dynamics (MD) simulation showed that the intermolecular forces between T-CNF and PVA were stronger than those within pure PVA. Additionally, the T-CNF/PVA-2 fiber film exhibited excellent antibacterial properties, achieving an inhibition rate of 99.99 % against S. aureus.

Constructing multifunctional polyvinyl alcohol composite hydrogels with human-like skin properties using polyaniline-coated boron nitride nanofibers

Flexible conductive nanofibers play a crucial role in constructing hydrogels with human-like skin properties. However, it is still a challenge to construct flexible conductive nanofibers with good comprehensive properties. In this paper, we prepare composite fibers with excellent comprehensive properties by coating polyaniline (PANI) on the surface of flexible boron nitride nanofiber (BNNFs) template. BNNFs-PANI/PVA multifunctional composite hydrogels are created through the integration of BNNFs-PANI as nanofillers with soft poly (vinyl alcohol) (PVA) matrix using a one-pot self-assembly method. The composite hydrogels exhibit outstanding plasticity, self-adhesion, and self-healing properties, with a self-healing efficiency reaching up to 96% within 120 s. Furthermore, the tensile strength of the composite hydrogels has been enhanced by 36%, with the elongation at break exceeding 1500%. The compressive strength of the composite hydrogels at 60% strain is increased by 62%. Beyond these mechanical and self-healing features similar to human skin, the composite hydrogels also can serve as electronic pen for painting on a touchable electronic screen, simulating the function of human skin. Moreover, the dynamic changes in the abundant conductive network contribute to the composite hydrogels’ high strain sensitivity. Compared with pure PVA hydrogels, it is improved by 29%. Notably, the strain sensitivity of the composite hydrogels is higher than that of most reported hydrogel sensors. Therefore, the composite hydrogels also can be employed as a real-time human motion sensor, capable of detecting and distinguishing various human movements. We believe that employing BNNFs as templates for crafting highly flexible and conductive nanofibers will foster the advancement of flexible conductive nanomaterials with comprehensive properties. Furthermore, the outstanding properties of the prepared composite hydrogels contribute to the ongoing development of conductive hydrogels with skin-like functionalities.

Nanofibrous electroconductive scaffolds composed of poly(vinyl alcohol) and modified polyaniline for skin tissue engineering application

AbstractNanofibrous electroconductive scaffolds were designed and fabricated using electrospinning approach based on a poly(vinyl alcohol)‐grafted polyaniline (PVA‐g‐PANI) and neat PVA with various PVA‐g‐PANI content for skin tissue engineering (STE) application. At first, phenylamine‐functionalized PVA macromonomer was synthesized, and then aniline was grafted onto macromonomer by an oxidation polymerization technique. The resultant PVA‐g‐PANI with different ratios was co‐electrospun with PVA to afford PVA‐g‐PANI/PVA electrically conductive nanofibrous scaffolds. Physicochemical features of the scaffolds, including water uptake properties, surface wettabilities, and morphologies as well as biological properties such as biodegradabilities, cytocompatibilities, cells adhesion and proliferation potentials, hemolysis rates, and protein adsorption capacities were investigated. Surface wettabilities of the scaffolds were altered from 55.7° for pure PVA up to 105.1° for the scaffold with the highest PVA‐g‐PANI content (30 wt%). It was found that the biodegradation rates of the scaffolds were decreased by increasing PVA‐g‐PANI content owing to very low biodegradation nature of PANI. Hemolysis assay revealed that all scaffolds were nonhemolytic (hemolysis rate <2%), except the scaffold that fabricated with 30 wt% of PVA‐g‐PANI. As results, the constructed scaffolds with 15 and 20 wt% of PVA‐g‐PANI (S3 and S4, respectively) exhibited higher potentials in both physicochemical and biological properties for STE application.

Physical properties of rutile-TiO2 Nanoparticles and effect on PVA/SiO2 hybrid films synthesized by sol-gel method

We use an ab-initio approach to analyze the structural, electronic band structure, and thermoelectric properties of titanium dioxide (TiO2 in rutile phase), and we then use rutile-TiO2 nanoparticles to determine its effects on sol-gel-produced polyvinyl alcohol/silicon dioxide (PVA/SiO2) hybrid films. The synthesis of hybrid films involved the incorporation of 1 % rutile-TiO2 nanoparticles in the PVA/SiO2 matrix. The thermoelectric properties of the resulting hybrid films were characterized by Seebeck coefficient measurements, as well as electrical and thermal conductivities. The synthesis of PVA/SiO2/Nano-TiO2 films was accomplished with success. The chemical bonds have amply demonstrated that the PVA backbone is connected to the (SiO2-TiO2) network. TGA testing indicates that hybrid films are more resistant to higher temperatures than pure PVA films. SiO2 nanoparticles reveal more effective loading to improve dielectric characteristics compared to TiO2. The best results are obtained in cases of mechanical, thermal and electrical insulation when both nanofillers are integrated into the polymer matrix. The findings show that the thermoelectric performance of PVA/SiO2 hybrid films is improved by the addition of (1 %) rutile-TiO2 nanoparticles in the rutile phase. This study provides insights into the potential applications of rutile-TiO2 nanoparticles in enhancing the thermoelectric properties of hybrid materials and opens up avenues for further research in this area, and contributes to the growing body of knowledge on enhancing the thermoelectric properties of materials by incorporating rutile-TiO2 nanoparticles into hybrid films synthesized by the sol-gel method.

Effect of MWCNTs surface functionalization on the characterization of PVA/MWCNTs nanocomposites

The present study aims to put forward the role of surface functionalization of multi-walled carbon nanotubes (MWCNTs) on the enhancement thermal and hydrophilicity properties of new nanocomposite based poly(vinyl alcohol)/surface functionalized MWCNTs (PVA/MWCNTs), prepared by a facile phase inversion process. In this study, the fabrication of PVA/MWCNTs nanocomposites is carried out using functionalized MWCNTs (f-MWCNTs) with different functional groups (–OH, –COOH, –NH2). The structural, morphological, thermal, hydrophilicity and physico-chemical properties of PVA/MWCNTs nanocomposites are characterized by XRD, FE-SEM, FT-IR, TGA and contact angle measurement. The FT-IR results confirm the formation of a hydrogen bond between MWCNTs and PVA chain. XRD analysis indicates an improvement in the crystallinity of the PVA/MWCNTs nanocomposite. TGA results reveal that the PVA/f-MWCNTs nanocomposites show higher thermal stability than pure PVA. It is revealed that PVA/MWCNTs nanocomposites based functionalized MWCNTs remarkably increase the degradation temperature, and thus enhancing the thermal properties. The highest weight loss (30.7 wt%) and degradation temperature (520 °C) values are obtained with PVA/f-MWCNTs(0.5 wt%). The contact angle measurement confirms that the hydrophobic properties of pure PVA became hydrophilic because of the functional groups of MWCNTs. The hydrophilicity of PVA/MWCNTs nanocomposites is increased with the increase in wt% of MWCNTs embedded in the nanocomposite.

Synthesis of ZIF-8/PVA microspheres with the assistance of a microfluidic device and their controlled drug release properties

ZIF-8/PVA microspheres with an even size were synthesized with the assistance of a simple microfluidic device. The ZIF-8/PVA microdroplets were first generated in a simple co-flow microfluidic device using a PVA aqueous solution dispersed with ZIF-8 nanoparticles as the dispersed phase and fatty acid methyl ester (FAME) as the continuous phase. Subsequently, the ZIF-8/PVA microdroplets were further extracted to form ZIF-8/PVA microspheres. The influence of the type of continuous phase on the sphericity of microspheres was investigated and the effect of ZIF-8 content was studied. Further studies showed that decreasing the extraction rate and using additives of NaCl in the dispersed phase could improve the sphericity of the ZIF-8/PVA microspheres. Finally, the synthesized ZIF-8/PVA microspheres were used to study the loading and release of tetracycline. The results showed that the loading of ZIF-8/PVA microspheres was more than 5 times higher than that of pure PVA microspheres. The drug release time of ZIF-8/PVA microspheres was much longer than that of the PVA microspheres and the release rate was significantly affected by the pH of the environment.

Synthesis and Rheological Analysis of Non-Isocyanate Polyurethanes Blended with Poly(vinyl alcohol)

This study investigated the blending of non-isocyanate polyurethanes (NIPUs) with poly(vinyl alcohol) (PVA) at various ratios, with specific emphasis on ratios such as 20%, 50%, 80%, and 100% NIPU content. Focus has been made on assessing their rheological behaviour, mechanical performance, and thermal stability. As the NIPU content surpassed 50%, a shear-thickening trend emerged, suggesting a highly interwoven molecular structure. Rheological studies demonstrate viscosity variations dependent on blend composition and shear rate, with pure NIPU solution exhibiting shear thickening behaviour suggestive of network formation facilitated by the application of shear. Dynamic modulus analysis revealed viscoelastic properties in blends containing 50% and 100% NIPU. Thixotropic analysis showcased a remarkable structural recovery of 99% in solutions with over 20% NIPU, emphasizing the resilience of NIPU-rich blends to shear-induced alterations. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) demonstrate thermal stability and crystallinity, with blends exhibiting intermediate behaviour and reduced crystallinity compared to pure PVA due to NIPU incorporation. Blends exceeding 10% PVA displayed reduced consistency and diminished PVA crystallization ability, corroborated by DSC and wide-angle X-ray diffraction (WXRD) results. Thermal stability increased with NIPU integration, and blends demonstrated intermediate thermal behaviour between the pure polymers. Notably, the PU2PVA8 blend demonstrates the highest miscibility and a unique combination of amorphous and crystalline nature, showcasing its potential for tailored material design with enhanced structural and thermal properties.

Development of Light, Strong, and Water-Resistant PVA Composite Aerogels.

A significant weakness of many organic and inorganic aerogels is their poor mechanical behaviour, representing a great impediment to their application. For example, polymer aerogels generally have higher ductility than silica aerogels, but their elastic modulus is considered too low. Herein, we developed extremely low loading (<1 wt%) 2D graphene oxide (GO) nanosheets modified poly (vinyl alcohol) (PVA) aerogels via a facile and environmentally friendly method. The aerogel shows a 9-fold increase in compressional modulus compared to a pure polymer aerogel. With a low density of 0.04 mg/mm3 and a thermal conductivity of only 0.035 W/m·K, it outperforms many commercial insulators and foams. As compared to a pure PVA polymer aerogel, a 170% increase in storage modulus is obtained by adding only 0.6 wt% GO nanosheets. The nanocomposite aerogel demonstrates strong fire resistance, with a 50% increase in burning time and little smoke discharge. After surface modification with 1H,1H,2H,2H-Perfluorodecyltriethoxysilane, the aerogel demonstrates water resistance, which is suitable for outdoor applications in which it would be exposed to precipitation. Our research demonstrates a new pathway for considerable improvement in the performance and application of polymer aerogels.

Incorporation of Magnetic Filler (Co0.2Zn0.2Cd0.6Fe2O4) in PVA Matrix and Studying the Structural, Optical and Mechanical Properties of Nanocomposite Films

AbstractThe goal of this study is to synthesize nanocomposite PVA/ Co0.2Zn0.2Cd0.6Fe2O4 films with varying contents of Co0.2Zn0.2Cd0.6Fe2O4 nanoparticles (x = 0, 0.2, 0.4, 0.6, 0.8) to improve the structural, optical, and mechanical characteristics of the examined materials. Casting technique is used to prepare PVA/ Co0.2Zn0.2Cd0.6Fe2O4 films. X-ray diffraction, FTIR, UV–Vis spectroscopy, and Vickers Hardness were used to examine the effect of magnetic nanoparticle content on the structural, optical, and mechanical characteristics of PVA nanocomposite films. The refractive index rises from 1.4967 for pure PVA to 7.6511 for PVA + 0.8Co0.2Zn0.2Cd0.6Fe2O4, allowing it to be employed in a variety of applications such as solar cell construction. Because of the presence of ferrite in the glass matrix, the average hardness values enhanced and increased from 90.7 to 114.2 MPa. The stress exponent (n) varies from 1.12 to 3.33, with grain boundary sliding as the deformation mechanism for x = 0, viscous glid for x = 0.2, 0.4, and 0.6, and dislocation climb for x = 0.8 nanocomposite thin films.