Poly Vinyl Alcohol Blend Research Articles

Tailoring the optical properties and electrical conductivity of polyvinyl alcohol/polyvinyl pyrrolidone filled with cobalt oxide nanoparticles for nanodielectric applications

The blends of hydrophilic polymers polyvinyl alcohol (PVA) (50 %) and polyvinyl pyrrolidone (PVP) (50 %) composite incorporated with various ratio of cobalt oxide nanoparticles (Co3O4 NPs) has been prepared and characterized. The structural characteristics of the prepared films were investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR). The XRD patterns confirmed the semi-crystalline nature of the PVA/PVP composite. It was also revealed that the degree of crystallinity decreased with increasing Co3O4 NPs content. FT-IR spectra confirm the interaction and complexation of Co3O4 NPs with PVA/PVP matrices. Optical parameters were determined by investigating the UV–Vis reflectance and transmittance spectra. As the amount of Co3O4 NPs increased, the band-gap values decreased, demonstrating the feasibility of Co3O4 NPs as band-gap-controlled optical materials for a variety of applications. As the concentration of Co3O4 NPs increases, leading to the presence of defect levels associated with the sample's density of localized states, the Eg value of the host matrix experiences a reduction, dropping from 5.25 to 4.03 eV for direct transitions and from 4.08 to 2.29 eV for indirect transitions. The conductivity and dielectric characteristics have improved after the addition of Co3O4 NPs. The σdc exhibited an increase from 4.76 × 10−8 to 3.67 × 10−5 Scm−1, while the frequency exponent S decreased from 0.82 to 0.74. Higher ε′′ values at lower frequencies were associated with amplified energy loss in the composite samples. Conversely, elevated ε′ values at lower frequencies were attributed to the prevailing impact of interfacial polarizations resulting from charge aggregation. Polarized films with the capacity to hold an electric charge are created by applying an electric field. Hence, these nanocomposites are suitable for application in flexible capacitors.

Preparation and tuning the optical and electrical properties of polyethylene oxide/polyvinyl alcohol/poly(3,4-thylenedioxythiophene): polystyrene sulfonate/CuO-based quaternary nanocomposites for futuristic energy storage devices

Polymeric nanocomposites have important industrial and scientific applications because they are flexible, multifunctional, and highly intelligent. Using the solution-casting technique, copper oxide nanoparticles (CuO NPs) of different concentrations (0.4, 0.8, 1.2, and 1.6 wt% to the host blend weight) were added to polymer nanocomposite films made of polyethylene oxide, polyvinyl alcohol, and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEO/PVA/PEDOT: PSS) blend. According to TEM and XRD studies, the CuO NPs of a size range of 20 to 60 nm were extremely pure and had a monoclinic structure. The PEO/PVA/PEDOT: PSS blend's semicrystalline character was reduced by the additional CuO NPs through interactions between the functional groups of blend and nanofiller, according to XRD and FTIR measurements. By adding more CuO NPs, the samples' optical bandgap energies, and UV/visible absorption spectra showed considerable changes. The electrical conductivity, impedance, and dielectric features of the samples were assessed at various frequencies, from 10−1 to 107 Hz. AC conductivity, dielectric permittivity, and dielectric loss all steadily improved as CuO NPs content rose and low permittivity at the high frequencies depicted the favourable nanodielectric features of these hybrid films. The equivalent electrical circuit using the impedance components Z′ and Z″ was introduced. The controllable optical energy gaps, frequency-dependent AC conductivity, and a large extent of composition tuneable permittivity implied the utility of PEO/PVA/PEDOT: PSS/CuO nanocomposites in developing flexible optoelectronic and energy storage devices.

Influence of cesium bromide nanoparticles on the structural, optical, electrical, and antibacterial properties of polyvinyl alcohol/sodium alginate for biological applications

AbstractThis study investigates the use of organic and inorganic nanostructures to create innovative functional materials with applications in optoelectronics devices. Specifically, nanocomposite films were created by incorporating different concentrations of cesium bromide nanoparticles (5, 10, and 15 wt%) into a polyvinyl alcohol (PVA) and sodium alginate (SA) polymer blend (50/50 wt%) through a solution casting process. The impact of CsBr NPs on the structural, optical, and electrical properties of the virgin PVA/SA matrix was systematically investigated. x‐ray crystallography investigation verified the semicrystalline nature of the PVA/SA. FTIR spectra showed the main vibrational peaks of PVA/SA, with their intensity decreasing after the addition of cesium bromide. Scanning electron microscopy images showed the formation of aggregations and the increase of roughness for the PVA/SA‐CsBr NPs 15 wt% nanocomposite sample. The UV/vis. absorption spectrum showed a decrease in the energy gap values, which decreased from 4.25 to 3.89 eV in the direct transition and decreased from 4.12 to 3.77 eV in the indirect transition. Furthermore, the electrical conductivity and dielectric properties demonstrated improvement with increasing concentration of CsBr NPs. The antibacterial efficacy against Staphylococcus aureus and Escherichia coli exhibited an upward trend with an increase in CsBr nanoparticle concentration. Overall, the results suggest the promising potential of these nanocomposite films for applications in optoelectronics and biological applications.Highlights XRD shows that the amorphousity is increased after addition CsBr NPs. FT‐IR confirms the interactions/complexation between PVA/SA polymeric matrix filled with CsBr NPs. Optical energy gap is decreased with increasing CsBr concentrations. SEM images show the prepared samples have a smooth surface and only have a few defects. By adding CsBr NPs the electrical conductivity is tremendously improved.

STRUCTURE DEVELOPMENT AND PROPERTIES OF PLASTICIZED PVA-STARCH-PADDY STRAW COMPOSITES

Paddy straw is often burnt in the fields or disposed of in ways that cause extensive environmental pollution. The present study focused on using paddy straw in bio-compostable composites fabricated with polyvinyl alcohol (PVA) and thermoplastic starch blends as a matrix. Locally available paddy straw was chopped, cleaned and treated with 15% NaOH solution for four hours. The alkali treatment produced changes in the crystal structure and surface morphology of the paddy straw. Then, it was dispersed in blends of PVA and starch solutions containing polyethylene glycol (PEG200) as plasticizer. The PEG200 acted as both plasticizer and compatibilizer, as evidenced by the single glass transition peak and the lower melting point of the film cast from these blends. These composite films had higher thermal stability, increased tensile strength, but also flexibility. These properties were associated with structure development with strong hydrogen bonding interaction between the paddy straw and PVA-starch blends, which was supported by results of characterization studies.

Fabrication and characterization of blue honeysuckle anthocyanins-loaded nanocomposite films and the application in pork preservation

In this experiment, blue honeysuckle anthocyanins (BHA) and nanocomplexes loaded with blue honeysuckle anthocyanins (NC-BHA) were added to a chitosan (CS)/polyvinyl alcohol (PVA) blend matrix for food packaging. The anthocyanin composition in blue honeysuckle and its nanocomplex were determined and analyzed. Meanwhile, the anthocyanins-loaded nanocomplexes and anthocyanin-containing films were measured and compared for their functionality and stability. The zeta potential, polydispersity index and average particle size of anthocyanins-loaded nanocomplexes were +31.80 mV, 0.379 and 659.5 nm, respectively. The encapsulation was effective under transmission electron microscope (TEM) observation. Although CS/PVA-free anthocyanin (CP-FA) film showed better pH sensitivity and oxidation resistance than that of the CS/PVA-anthocyanin nanocomplex (CP-AN) film in short term, the CP-AN film were found to be more stable than the CP-FA film after 30 days at high temperature and light radiation. In summary, the CP-AN film possessed better mechanical property, thermal stability, denser microstructure, higher water vapor barrier, stronger intermolecular interactions and more stable pH sensitivity and oxidation resistance than those of the CP-FA film. Finally, three films were used in the preservation of pork, CP-AN film also showed better antibacterial properties and more durable antioxidant properties. Therefore, CP-AN film was promising active packaging material in pork preservation in our experiment.

CSMP: A Self-Assembled Plant Polysaccharide-Based Hydrofilm for Enhanced Wound Healing.

Wound management remains a critical healthcare issue due to the rising incidence of chronic diseases leading to persistent wounds. Traditional dressings have their limitations, such as potential for further damage during changing and suboptimal healing conditions. Recently, hydrogel-based dressings have gained attention due to their biocompatibility, biodegradability, and ability to fill wounds. Particularly, polysaccharide-based hydrogels have shown potential in various medical applications. This study focuses on the development of a novel hydrofilm wound dressing produced from a blend of chia seed mucilage (CSM) and polyvinyl alcohol (PVA), termed CSMP. While the individual properties of CSM and PVA are well-documented, their combined potential in wound management is largely unexplored. CSMP, coupled with sorbitol and glycerin, and cross-linked using ultraviolet light, results in a flexible, adhesive, and biocompatible hydrofilm demonstrating superior water absorption, moisturizing, and antibacterial properties. This hydrofilm promotes epithelial cell migration, enhanced collagen production, and outperforms existing commercial dressings in animal tests. The innovative CSMP hydrofilm offers a promising, cost-effective approach for improved wound care, bridging existing gaps in dressing performance and preparation simplicity. Future research can unlock further applications of such polysaccharide-based hydrofilm dressings.

Characterization of carbon nanotubes reinforced PVOH polymer composites added with calcined clam shells with the presence of electron beam irradiation

AbstractThe objective of this research is to scrutinize the effect of electron beam irradiation and filler (calcined clam shell and carbon nanotube) addition on the characteristics of the resulting polyvinyl alcohol (PVOH) blends. Herein, PVOH/calcined clam shells/carbon nanotube (CNT) blends were prepared by solution casting, which followed by electron beam irradiation treatment at the irradiation dosage of 10 and 30 kGy. It was revealed that the addition of CNT and calcined clam shell enhances the tensile strength and elongation at break at 10 kGy irradiation dosage. On the other hand, when 30 kGy irradiation was applied on PVOH blends, high loading of calcined clam shell reduces the tensile strength and elongation at break, while increasing the loading of CNTs increases the tensile strength and elongation at break of PVOH blends. For scanning electron microscope (SEM) analysis, the amount of fibrous presence in fractured part of PVOH blend increased and size of fibrous became thinner and longer when irradiation increased. Besides, a smoother surface can be observed with increased loading of CNTs, while more fibrous are observed with increased of calcined clam shell.

Synthesis and characterization of sulfonated chitosan (SCS) / sulfonated polyvinyl alcohol (SPVA) blend membrane for microbial fuel cell application

We have reported the synthesis of newly blended membranes, SPVA/SCS, using the solution-casting and solvent evaporation technique. The selection of appropriate polymers is crucial for the synthesis of polymer electrolyte membranes (PEMs). Considering factors such as film-forming ability, cost-effectiveness, ease of handling, availability, and proton conductivity, we optimized the blend of polyvinyl alcohol (PVA) and chitosan polymers. To enhance the proton conductivity of the blend membrane, the sulfonic group was incorporated into the polymer chain through a sulfonation process. We successfully synthesized SPVA/SCS membranes by varying the mass ratios of SPVA/SCS, specifically 90:10, 50:50, and 10:90. The thermal stability and chemical structure of the blend membrane were analyzed using Thermogravimetric and FTIR techniques. Moreover, a multicore design of microbial fuel cell was used to analyze the performance of membrane. The membrane was kept inside the cell for 48 h and the maximum voltage and current obtained was found to be 630–750 mV and 0.93–1.03 mA respectively.

Facile synthesis of PVA-formamide based solid state electrolyte membrane: A combined experimental and computational studies

For ever-growing energy demand, it is the imperative of time to develop advanced electrolyte materials which are compatible with Li + ion mobility in Lithium based batteries. In this study, polyvinyl alcohol (PVA)-LiNO3-Formamide (PLF) membrane complex has been developed for cost effective and mass fabrication of Li ion based energy storage devices. Improved Li + ion conducting PVA based polymer electrolytes in seven different PVA and LiNO3 blend compositions were prepared and characterized. Incorporation of Formamide (0.5 g) as plasticizer in the PVA-LiNO3 polymer matrix leads to a remarkable improvement in ionic conductivity (4.18 × 10−4 Scm−1) for a 0.27 g of LiNO3 concentration at ambient temperature. Improvement in Li conductivity is due to change in crystalline nature as a consequence of PVA O-H---O intra/inter molecular H-bonding destabilization. Investigation on the trend of activation energy as a function of dopant concentration indicates that the activation energy decreases up to 0.27 g of LiNO3. Lowest activation energy 0.21 eV is observed for this concentration. More interestingly, improved Lithium Transference Number (LITN) of 0.437 is obtained through Bruce-Vincent approach for the plasticized optimum conducting membrane (PLF4–0.27 g LiNO3 concentration) which is better than that of the commercially available Li batteries. Underlying molecular level interactions in the models of PVA and its complexes were explored using M05-2×/6–31 + G (d,f) levels of theory and NCI analysis. From the least interaction energy of PVA-Formamide complex, it is inferred that metal-Oxygen coordination contributes much for the stabilization of PVA-LiNO3-Formamide, PVA-LiNO3, Formamide-LiNO3 complexes.

Investigation on polyvinyl alcohol and sodium alginate blend matrix with ammonium nitrate conducting electrolytes for electrochemical applications

Polyvinyl alcohol (PVA) Sodium alginate (NaAlg) polymer composites were synthesized by solution casting technique and doping with ammonium nitrate (NH4NO3). The functionalization structure of the produced electrolytes was investigated using XRD and AC impedance spectroscopy. XRD confirms amorphous nature. The ionic conductivity of the electrolytes is evaluated using ac impedance measurements at temperatures ranging from 303 to 353 K. PVA: NaAlg: NH4NO3 (60:40:15 wt%) blend polymer electrolyte was observed to have the highest conductivity of 1.05 × 10−6 S cm−1. The Arrhenius plot appears to be obeyed by the temperature dependent ionic conductivity and is of non-debye type. Activation energy for best conducting electrolyte was 0.2364 eV. The dielectric relaxation of the polymer electrolyte has been studied, and the results are described. Relaxation time estimated from loss tangent analysis also affirms that value is low for highest conducting sample. Results of CV and LSV studies gave a plausible approach for electrochemical application.

A Study on Biodegradable Water Soluble Film Based on Blend of Polyvinyl Alcohol and Modified Thermoplastic Cassava Starch

A Study on Biodegradable Water Soluble Film Based on Blend of Polyvinyl Alcohol and Modified Thermoplastic Cassava Starch

Polyvinyl alcohol composite gel membrane modified by natural polysaccharide and waterborne polyurethane

AbstractA new composite gel material was obtained by blending polyvinyl alcohol (PVA) aqueous solution with sodium alginate (SA), sodium carboxymethyl cellulose (CMC‐Na), waterborne polyurethane (WPU), and polyvinylpyrrolidone (PVP). Titanium dioxide nanoparticles (nTiO2) were doped as an antibacterial agent. The liquid composite could to form a transparent protective gel membrane. The microstructure of the gel membrane was observed via scanning electron microscopy, and the intermolecular interaction was investigated by total reflection infrared spectroscopy. The results demonstrated a homogeneous phase and significant hydrogen bonding between chain segments. The best results indicated that the equilibrium swelling rate increased from 147% to 170%, the 3‐h water vapor transmission rate increased from 279.41 g/m2∙day to 374.75 g/m2∙day, and the water contact angle increased from 16.8° to 60.7°, relative to the PVA substrate. The properties of this composite gel material suggest possible biomedical usage, particularly in skin and wound protection scenarios.Highlights A novel gel film‐forming material consisting of a viscous liquid is prepared. Adding polysaccharides modifiers resulted in significant improvements of the performance. The bacteriostatic and antihemorrhagic properties are introduced to the material. Low‐irritating materials were used to prepare the gel material.

Effect of Polydopamine and Curcumin on Physicochemical and Mechanical Properties of Polymeric Blends.

In this study, we prepared composites made from polyvinyl alcohol (PVA), sodium alginate (SA), curcumin (Cur), and polydopamine (PD). The film-forming properties of the composites were researched for potential wound-healing applications. The structures of the polymer blends and composites were studied by FTIR spectroscopy and microscopic observations (AFM and SEM). The mechanical properties were measured using a Zwick Roell testing machine. It was observed that the formation of a polymeric film based on the blend of polyvinyl alcohol and sodium alginate led to the generation of pores. The presence of curcumin in the composite resulted in the alteration of the blend properties. After solvent evaporation, the polymeric blend of PVA, SA, and curcumin formed a stable polymeric film, but the film showed poor mechanical properties. The addition of polydopamine led to an improvement in the mechanical strength of the film and an increase in its surface roughness. A polymeric film of sodium alginate presented the highest surface roughness value among all the studied specimens (66.6 nm), whereas polyvinyl alcohol showed the lowest value (1.60 nm). The roughness of the composites made of PVA/SA/Cur and PVA/SA/Cur/PD showed a value of about 25 nm. Sodium alginate showed the highest values of Young's modulus (4.10 GPa), stress (32.73 N), and tensile strength (98.48 MPa). The addition of PD to PVA/SA/Cur led to an improvement in the mechanical properties. Improved mechanical properties and appropriate surface roughness may suggest that prepared blends can be used for the preparation of wound-healing materials.

A novel PVA/MWCNTs hydrogel with high toughness and electromagnetic shielding properties

AbstractCarbon nanotubes (CNTs) are widely utilized as conductive fillers due to their high conductivity, lightweight, and ease of modification. However, their poor dispersion limits their otherwise excellent performance. In this study, we successfully prepared a high toughness, strong electromagnetic interference (EMI) shielding hydrogel by blending polyvinyl alcohol (PVA) hydrogel with multi‐walled carbon nanotubes (MWCNTs) modified by anionic surfactant sodium dodecylbenzene sulfonate (SDBS) and (3‐aminopropyl) triethoxysilane (KH550). We found that the modifiers can not only promote the uniform dispersion of MWCNTs but also improve the mechanical properties of the hydrogel. The results demonstrate that the stress (≈14.86 MPA), elongation at break (233.9%), and compressive strength (≈2.89 MPA) of PVA/MWCNTs composite hydrogel with 1 wt% MWCNTs and 5 wt% PVA were increased by 533.6%, 241.4%, and 206.5%, respectively. Encouragingly, the total electromagnetic shielding effectiveness (SET) is 123.6 dB at a thickness of 5 mm. In summary, this work provides a general approach to functionalizing MWCNTs, which has great potential for developing EMI shielding materials with high toughness.

Stretchable polyvinyl alcohol and sodium alginate double network ionic hydrogels for low-grade heat harvesting with ultrahigh thermopower

Recently, employing ionic thermoelectric (i-TE) materials is regarded as a promising strategy to harness low-grade waste heat due to their remarkable ionic Seebeck coefficient. By blending polyvinyl alcohol (PVA), sodium alginate (SA), and polyethylene glycol (PEG) and additional freeze-thaw method, PVA/SA/PEG hydrogel is developed. Via immersing the hydrogel in NaBF4 solutions with different concentrations, the TE and mechanical properties could be adjusted. PVA/SA/PEG/NaBF4-1.5 M hydrogel demonstrates exceptional mechanical properties, with tensile stress and strain up to 69 kPa and 114%, respectively. Moreover, PVA/SA/PEG/NaBF4-1.5 M hydrogel exhibits a high ionic conductivity of 31.4 mS/cm, a maximum ionic Seebeck coefficient of 66.7 mV/K, and an impressive power factor of 13.96 mW/m/K2. These outstanding performances originate from the synergistic effect of Manning's counterion condensation facilitated by SA and the crystal PVA chains. The prototype application of the PVA/SA/PEG/NaBF4-1.5 M hydrogel is demonstrated by a flexible ionic thermoelectric supercapacitor. With the external load resistance is 90 kΩ, the energy collected in one thermal cycle could achieve 4 mJ. This study introduces the exceptional stretchable PVA/SA/PEG/NaBF4 hydrogels with a record-high ionic Seebeck coefficient as promising i-TE materials for future TE application in low-grade waste heat.

Developing a pachyman/polyvinyl alcohol-polylactic acid bilayer film as multifunctional packaging and its application in cherry tomato preservation

Polyvinyl alcohol (PVA) is a widely used biodegradable material, but its high solubility and water vapor permeability limit its applications in food packaging. To address this issue, bilayer films were developed based on the combination of blending and coating techniques in the study, which consisted of an inner pachyman (PM)/PVA blend layer and an outer polylactic acid (PLA) layer. Blending PVA with PM reduced the solubility and oxygen permeability of the film, and the blend matrix showed rapid self-healing capabilities. Loading of a thin PLA shell onto the PM/PVA layer improved the water resistance, tensile strength, stiffness and water vapor barrier of the developed bilayer films. The best overall performance of the bilayer film was achieved using 40 g/L PLA as the film-forming solution. Infrared spectroscopic and microscopic structure analysis revealed weak interfacial interaction of the bilayer film. Furthermore, this bilayer film showed a better preservation effect on cherry tomatoes compared with PVA, polyethylene, and PM/PVA films. The physicochemical quality of fruits could be effectively preserved for at least 10 days under ambient environment. It is anticipated that the bilayer film developed here serves as a promising candidate for food packaging materials to extend the shelf life.

Using Pegylated Graphene Oxide to Achieve High Performance Solid Polymer Electrolyte Based on Poly(ethylene oxide)/Polyvinyl Alcohol Blend (PEO/PVA).

Solid polymer electrolytes (SPEs) have emerged as a promising avenue for developing flexible lithium-ion batteries. However, the low ionic conductivity of polymers remains a primary challenge that has been the subject of intensive research efforts in recent years. In this work, polyethylene oxide (PEO), polyvinyl alcohol, lithium perchlorate (LiClO4), and graphene functionalized with polyethylene glycol (FGO) have been used to prepare SPE/FGO electrolytes by casting solution technique. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) confirmed the reduction of SPE crystals and the increase of amorphous phases. The results demonstrated that the presence of functionalized graphene had an effective role in reducing crystallinity. Furthermore, the thermal and mechanical stability of the samples were corroborated through thermogravimetric analysis (TGA) and tensile tests, respectively. Notably, the samples exhibited adequate ionic conductivity at room temperature, with the highest ionic conductivity of 5.2 × 10-5 S·cm-1 observed for 2%wt of FGO in SPE (SPE/FGO(2)).

Development of a Solid Bio‐Electrolyte from a Seaweed Extract – Polyvinyl Alcohol Blend for Primary Mg‐Ion Conducting Batteries

AbstractA novel solid bio‐electrolyte from seaweed acts as a potential candidate for electrolytes in batteries by solution casting technique. The ethanol extract of seaweed Sargassum Muticum (SME) is blended with PVA to prepare the bio‐membrane and along with MgCl2 as the ionic provider, a solid bio‐electrolyte is produced. The ionic conductivity of the prepared bio‐membrane, 1 g SME+0.8 g PVA is 1.57×10−6 S cm−1. XRD analysis affirms the amorphous nature of the prepared bio‐electrolytes and the highest degree of amorphous nature is apparent for the composition of 1 g SME+0.8 g PVA+0.7 wt% MgCl2. Complex formation between the SME, polyvinyl alcohol, and the added charge carrier has been made evident from the FTIR technique. Thermal properties of the bio‐electrolytes by differential scanning calorimetry (DSC) are supported by the low Tg. Electrochemical impedance analysis for the prepared bio‐electrolytes and the maximum ionic conductivity of 2.22×10−3 S cm−1 is exhibited by 1 g SME+0.8 g PVA+0.7 wt% MgCl2 membrane. A primary magnesium‐ion conducting battery has been constructed with the highest conducting bio‐electrolyte membrane and an open circuit voltage of 2.18 V validates the application of this bio‐membrane as a promising solid electrolyte for energy storage devices.

Effective nanomembranes from chitosan/PVA blend decorated graphene oxide with gum rosin and silver nanoparticles for removal of heavy metals and microbes from water resources

Fabricating an effective bio-adsorbent based on functional spots can surely be able to eliminate numerous of heavy metals and pathogens from contaminated water resources. Thus, this study aimed to fabricate depollution bionanomembranes based on amalgamated the decorated graphene oxide (GO) with antibacterial natural rosin and silver (Ag) NPs inside chitosan (CS)/polyvinyl alcohol (PVA) blend by the solvent-casting route. The nanostructure of prepared GO nanoplatelets and its decoration are investigated by X-ray diffraction (XRD). Various ratios from decorated GO (i.e., 1, 2 and 3 wt.%) are utilized to prepare CS/PVA nanomembranes. The structure and surface topography of casted nanomembranes are analyzed by XRD and SEM. The obtained outcomes revealed that the use of decorated GO, especially at 2 wt.%, increased the tensile strength to ∼ 48 MPa compared to the unfilled blend (33 MPa). Other investigations such as thermal stability and antibacterial properties are also conducted on the casted CS/PVA nanomembranes. Moreover, depollution of heavy metals is explored through adsorption into the polymeric membranes at ambient temperature and pH 4–6. The gotten results supported that CS/PVA-3% NPs membrane possessed higher adsorption property towards the selective metal ions (i.e., 85–99.7% depending on the metal ion type) compared to other nanomembranes. However, the tensile strength achieved for the nanomembrane containing 2 wt.% nanoplatelets. The impact of pH, temperature, contacting time, and bacterial colony counting on CS/PVA-3% NPs is also studied, in addition to the recovery and reusability of adsorbent. Furthermore, kinetic and isothermal models are suggested to depict the adsorption efficacy of CS/PVA-3% NPs membrane. The obtained data showed that CS/PVA-3% membrane is a promising candidate to be utilized for removal of heavy metals and biological species from water resources for irrigation and agricultural applications.

Preparation and characterization of N-isopropyl acrylamide grafted polyvinyl alcohol and chitosan blend films with hydrophobic and antibacterial properties

One of Polyvinyl alcohol (PVA) films' well-recognized weaknesses is moisture sensitivity, which limits their applications. Various techniques have been employed to improve their hydrophobicity, such as blending and hydrophobic coating, but they have shown issues with compatibility and stability. In this study, a new method was proposed to modify PVA by grafting N-isopropyl acrylamide (NIPA) and blending it with chitosan (CS) to enhance its hydrophobic and antibacterial properties. The chemical structure of PVA-NIPA was characterized by FT-IR, 1H NMR, and XRD. By forming chemical bonds between PVA and NIPA through Michael's addition reaction, the moisture sensitivity of the film was significantly reduced. Additionally, the contact angle (CA) increased to 107.85° and the water vapor transmission rate (WVTR) decreased from 17.69 g / (m2h) to 6.53 g / (m2h). The PVA-NIPA/CS film also exhibited excellent mechanical properties, with Young's modulus of 303.67 MPa, tensile strength of 28.86 MPa, and elongation at break of 330.25%. Moreover, it showed better compatibility, high transparency, good UV-blocking properties, and strong antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), reducing the total colony counts by 2.53 and 3.44 logs, respectively. Thus, this work has generated new insights for expanding the application range of PVA films in packaging materials.