Groups Of PVA Research Articles

Facile strategy of Fe3+ rich collagen-based composite hydrogel for antibacterial, electricity harvesting and sensing applications

Conventional hydrogels have poor conductivity and low stretchability, limiting their practical applications for different purposes. Herein, collagen (CL) based, poly(vinyl alcohol) (PVA) and glutaraldehyde (GT) cross-linked ferric ion (Fe3+) rich highly conductive CL/GT/PVA/Fe hydrogel was developed. The presence of high CL, PVA and Fe3+ ions, together with the effective Fe3+ complexes formation, delivers the hydrogel with some particular assigns, such as high ionic conductivity (3.44 S.m−1) and antibacterial activity; furthermore, a very high stretchability. The CL/GT/PVA/Fe hydrogel demonstrated excellent mechanical properties, where the highest tensile strength of the hydrogels was ∼204.5 kPa at an elongation of 674 %, and the highest compressive strength was ∼0.39 MPa, with the highest stretchability of 81.67 %. The strengths are enhanced significantly by the incorporation of Fe3+ ions because of the formation of effective complexation of Fe3+ with rich hydroxyl and carboxyl groups of PVA and CL. As a flexible strain sensor, the CL/GT/PVA/Fe hydrogel with excellent conductivity manifests high sensitivity in human motion monitor. The hydrogels’ sufficient –OH and –COOH groups play a key role in imparting moist-induce electricity supply and the highest 173 mV of open circuit voltage (Voc) generated during moisture spray.

Ice growth inhibition by poly(vinyl alcohol): Insights from near-infrared spectroscopy and molecular dynamics simulation

Poly(vinyl alcohol) (PVA) is a well-known ice recrystallization inhibitor, yet its antifreeze mechanism remains debated. Here, the mechanism of PVA is elucidated by means of near-infrared spectroscopy and molecular dynamics (MD) simulations. Analysis of the spectra of PVA solutions during the ice growth process reveals a dynamic interaction conversion from PVA-water to PVA-ice, indicating that PVA inhibits ice growth by directly binding to ice. Moreover, we observed OH binding to the ice surface through one or two hydrogen bonds but did not witness the previously reported formation of three hydrogen bonds when the OH group perfectly embeds into the ice crystal lattice. In addition, the spectral feature of CH2 groups of PVA indirectly indicates their significant contribution to inhibiting ice growth through hydrophobic interactions. The MD simulations further confirm the effective roles of both OH and CH2 groups for inhibiting ice growth.

Poly (vinyl alcohol)/Polyquaternium-7 Anion Exchange Membranes for Alkaline Polymer Electrolyte Fuel Cells

Anion exchange membrane (AEM) is one of the critical components in Alkaline polymer electrolyte fuel cells. This is due to the crucial function in facilitating the process of hydroxide ion conduction. A series of anion exchange membranes (AEMs) were synthesized using poly (vinyl alcohol) (PVA) as the backbone polymer and polyquaternium-7 as the copolymer that provides a hydroxide conducting group source. Thermal and chemical crosslinking was introduced to reduce the excessive swelling of the membranes. The effect of the PVA/PQ7 mass ratio on AEMs performance was investigated. The FTIR study reveals that the spectra exhibit the primary functional groups of PVA, polyquaternium-7, and chemical crosslinking. According to the SEM image, the PVA/PQ7 membranes have smooth and uniform morphology. Water uptake and swelling degree increased with increasing mass ratio of polyquaternium-7 to PVA. AEMs with a polyquaternium-7 to PVA ratio of 0.5 provide the highest IEC and hydroxide conductivity values of 1.52 mmol/g and 9.26 mS/cm at room temperature, respectively.

Mechanisms underlying the stability and instability of concentrated oil-in-water emulsions: Effect of the chemical structure of amphiphilic polymers

Despite extensive experimentation to efficiently prepare concentrated oil-in-water (O/W) emulsions with sufficient stability, the effect of the chemical structure of the polymeric surfactants on the emulsion stability is not yet understood in detail at the molecular level. We investigated the effect of the degree of saponification and arrangement of the hydrophobic (acetyl) groups of poly(vinyl alcohol) (PVA) on the stability of the concentrated emulsion via a combination of experiments and coarse-grained molecular simulations. This was accomplished by varying the degree of saponification and the arrangement of the hydrophobic groups on PVA, and by systematically changing the volume fraction of PVA molecules. The stability of the emulsion was adversely affected by the presence of an excess or the complete absence of hydrophobic groups on PVA. The former situation promotes the aggregation of PVA molecules with each other; conversely, fully saponified PVA molecules penetrate the water phase, thereby decreasing the number of PVA molecules at the O/W interface. Thus, the depletion of the interface of PVA molecules increases the interfacial tension, and, consequently, destabilizes the interface. Adjustment of the degree of saponification to a suitable value (80%) led to the formation of stable, concentrated emulsions with a smaller amount of PVA. For PVA with an appropriate degree of saponification, the interfacial behavior of concentrated O/W emulsions was to a lesser extent affected by the arrangement of the hydrophobic groups of PVA compared to the degree of saponification. Furthermore, the individual PVA chains at the interface had planar conformations, regardless of the arrangement of the hydrophobic groups. Our results indicate that careful tuning of the degree of saponification, rather than the arrangement of the hydrophobic groups of PVA, is necessary to control the interfacial stability of concentrated O/W emulsions using PVA. The findings of this study provide support for departing from empirical trial-and-error approaches and may facilitate the development of emulsifiers with enhanced performance.

Role of high hydrostatic pressure pretreatment on the formation of electrospun nanofibers from soy protein isolate/polyvinyl alcohol

In this research, the characteristics of the high hydrostatic pressure (HHP)-treated soy protein isolate (SPI) solutions as well as HHP-treated SPI (HSPI) electrospun fibers were comprehensively studied for the first time. For this purpose, surface tension, electrical conductivity, viscosity, zeta potential, and secondary structure of HSPI solutions at different ratios were investigated. Also, differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) of HHP-treated and non-treated SPI: PVA nanofibers were thoroughly compared. HHP denaturation reduced the size of nanofibers by 50–100 nm, diminished ordered structures and crystallinity of nanofibers, increased their melting point and induced hydrogen bonding between amino groups of denatured SPI and hydroxyl groups of PVA. These findings open a new horizon in the successful application of non-thermal energies in the electrospinning process to achieve appropriate fibers at nanoscale.

Preparation of an Aminated Lignin/Fe(III)/Polyvinyl Alcohol Film: A Packaging Material with UV Resistance and Slow-Release Function.

To reduce the usage of petroleum-based plastic products, a lignin-based film material named aminated lignin/Fe(III)/PVA was developed. The mixture of 8 g lignin, 12 mL diethylenetriamine, 200 mL NaOH solution (0.4 mol·L-1), and 8 mL formaldehyde was heated at 85 °C for 4 h; after the aminated lignin was impregnated in the Fe(NO3)3 solution, a mixture of 3 g aminated lignin/Fe(III), 7 g PVA, and 200 mL NaOH solution (pH 8) was heated at 85 °C for 60 min; after 2 mL of glycerin was added, the mixture was spread on a glass plate to obtain the aminated lignin/Fe(III)/PVA film. This film demonstrated hydrophobicity, an UV-blocking function, and a good slow-release performance. Due to the formation of hydrogen bonds between the hydroxyl groups of lignin and PVA, the tensile strength, the elongation at break, and the fracture resistance of the film were 9.1%, 107.8%, and 21.9% higher than that of pure PVA film, respectively. The iron content of aminated lignin/Fe(III)/PVA was 1.06 wt%, which mainly existed in a trivalent form. The aminated lignin/Fe(III)/PVA film has the potential to be used as a food packaging material with anti-ultraviolet light function and can also be developed as other packaging materials, such as seedling bowls, pots for transplanting, and coating films during transport.

UV-cured polyvinyl alcohol-MXene mixed matrix membranes for enhancing pervaporation performance in dehydration of ethanol

In this study, Ti3C2Tx MXene nanosheets were synthesized and loaded into UV-curable acrylate polyvinyl alcohol (APVA) to fabricate a novel APVA-MXene mixed matrix membrane (MMM) for ethanol dehydration by pervaporation (PV) process. UV-curable APVA was synthesized by substituting the hydroxyl groups of PVA with the methacryloyl groups of glycidyl methacrylate (GMA). A rapid and energy-efficient method for fabricating the active layer was achieved by UV-crosslinking of APVA over a 2-min period. The morphology, crystal structure, chemical composition, and thermo-mechanical properties of the membranes were investigated by FESEM, XRD, FTIR, TGA, and static mechanical stretching. Incorporating MXene nanosheets into the APVA matrix resulted in an increase in permeation flux and separation factor for APVA-MXene MMMs due to its laminated structure with interlayer transport channels of two dimensions, excellent compatibility with the polymer matrix, and high surface hydrophilicity. When the MXene loading reached 3 wt%, the optimal separation performance was achieved with a permeation flux of 942 g/(m2.h) (increased by 106% compared to pristine APVA membranes) and a separation factor of 294 (increased by 79% compared to pristine APVA membranes).

The Effects of Urea and Caprolactam on the Diffusion Behavior of Water in Polyvinyl Alcohol (PVA): A Molecular Dynamics Simulation Study

The effects of compound plasticizer urea/caprolactam (UC) on the diffusion behavior of water in mixtures with poly(vinyl alcohol) (PVA) were studied using a Molecular Dynamics (MD) simulation method. Five simulation models of PVA composites with different plasticizer contents were constructed to investigate the variation of the intermolecular interaction as well as the diffusion behavior of water molecules. Results showed that the predominant interaction between the functional groups of UC and PVA consisted of hydrogen bonds. As the plasticizer content increased, diffusion coefficients of water in PVA systems increased due to the comparably weak diffusion resistance. It was also found that the rotation of the PVA chains and the small molecules became faster with increasing UC content, and the relaxation time became shorter.

MIL-100 (Fe) integrated fibrous polyvinyl alcohol graft on cellulose acetate towards the development of green membranes; Application in multi solute rejection

Biodegradable cellulose acetate (CA) based membrane is grafted with poly(vinyl alcohol) (PVA) which is stabilized by citric acid (ca) (via electrospinning) and cured thermally to obtain water stable, robust cross-linked CA membrane. A high surface area metal organic framework (MOF) namely MIL-100(Fe) is electrospun with PVA nanofiber to achieve more functionalized nanocomposite grafting. Thermal curing allows cross-linking between the functional groups of CA, PVA and MOF which facilitates grafted PVA nanofibers to remain intact on the CA surface during filtration. The physicochemical properties and morphology of composite membranes are determined using various spectroscopy and microscopy tools. The performance of electrospun membrane composites were assessed for the treatment of humic acid (HA), heavy metal ions, dyes and sulfate salts. The results indicate that the hydrophilicity of membranes enhanced significantly upon coating a MOF functionalized nanofiber layer on CA membrane. The prepared composite membranes show rejection efficiency of > 90% for HA, Pb2+ and Cd2+ and nearly 70% for MgSO4 and Na2SO4 salts. Remarkable flux up to ten times more than the recently reported nanofiber reinforced membranes is achieved. In summary, this study provides an insight into designing of effective CA membranes by engineering various MOF - electrospun nanofibers for greater permeability and removal of various solutes.

QPVA-Based Electrospun Anion Exchange Membrane for Fuel Cells

The anion exchange membrane is one of the core components that play a crucial and inseparable role in alkaline anion exchange membrane fuel cells. Anion exchange membranes (AEMs) were prepared from quaternary ammonium poly(vinyl alcohol) (QPVA) by an electrospinning method. QPVA was used both as material for electrospun fiber mats and as filler for the inter-fiber void matrix. The objective of this work is to investigate the influence of the inter-fibers void matrix filler concentration on the properties and performance of eQPVA-x AEMs. FTIR spectra were used to identify the chemical structures of the AEMs. The primary functional groups of PVA and quaternary ammonium-based ion conducting cation were detected. The surface morphology of QPVA nanofiber mats and eQPVA-x AEMs was observed using SEM. Electrospun nanofiber structures of QPVA with an average size of 100.96 nm were observed in SEM pictures. The ion exchange capacity, swelling properties, water uptake, and OH-ions conductivity were determined to evaluate the performance of eQPVA-x AEMs. By incorporating the QPVA matrix of 5 wt.% concentration, the eQPVA-5.0 AEMs attained the highest ion exchange capacity, water uptake, swelling properties, and OH− conductivity of 0.82 mmol g−1, 25.5%, 19.9%, and 2.26 m×s cm−1, respectively. Electrospun QPVA AEMs have the potential to accelerate the development of alkaline anion exchange membrane fuel cells.

Simple fabrication of PVA/PEG blend doped with methyl blue dye with superior optical limiting performance: Enhanced luminescence property, structural, and dielectric properties

Using the casting technique, films of 90 wt% PVA/ 10 wt% PEG blend doped with numerous concentrations of methyl blue dye (MYB) were prepared. The effect of methyl blue dye on the unique functional groups of PVA and PEG was detected using a Fourier Transform infrared (FT-IR) spectrometer. The PVA/PEG blend's semi-crystalline characteristic was discovered via the X-ray diffraction pattern. With a rise in MYB doping concentration, the crystallinity of the doped blends degrades. The optical characteristics of the PVA/PEG mixture and the PVA/PEG mixture doped with various concentrations of (MYB)have been measured, including the absorption, transmission, reflection spectra, optical energy gap, optical absorption coefficient, and extinction coefficient. As the MYB dye's weight percentage increases, the composites show a decreasing energy gap and an increasing refractive index. As MYB doping rose, Urbach's energy surged from 8.5 meV to 28.88 meV. (PVA-PEG)/MYB composites demonstrated acceptable optical limiting characteristics. The emission peaks in terms of photoluminescence characteristics shiftto red with rising MYB content in (PVA-PEG)/MYB MYB composite sample films, with the peak emission occurring at wavelength λem = 600 nm. According to research done in the frequency range of 100 Hz to 1 MHz, the MYB contents impact the dielectric characteristics and AC electrical conductivity. All of the aforementioned characteristics point to the (PVA-PEG)/MYB polymer composite as a promising choice for laser filters, solar cell technology, electric energy storage, and different optoelectronic applications.

Fabrication and Evaluation of Polyvinyl Alcohol/Corn Starch/Patchouli Oil Hydrogel Films Loaded with Silver Nanoparticles Biosynthesized in Pogostemon cablin Benth Leaves’ Extract

Research on the manufacture of hydrogel films from polyvinyl alcohol, corn starch, patchouli oil, and silver nanoparticles, (PVA/CS/PO/AgNPs, respectively) was completed. The silver nanoparticles used in this study resulted from green synthesis using local patchouli plants (Pogostemon cablin Benth). Aqueous patchouli leaf extract (APLE) and methanol patchouli leaf extract (MPLE) are used in the synthesis of phytochemicals (green synthesis), which are then blended in the production of PVA/CS/PO/AgNPs hydrogel films, which are then cross linked with glutaraldehyde. The results demonstrated that the hydrogel film was flexible, easy to fold, and free of holes and air bubbles. The presence of hydrogen bonds between the functional groups of PVA, CS, and PO was revealed using FTIR spectroscopy. SEM analysis revealed that the hydrogel film was slightly agglomerated and did not exhibit cracking or pinholes. The analysis of pH, spreadability, gel fraction, and swelling index showed that the resulting PVA/CS/PO/AgNP hydrogel films met expected standards except for the organoleptic properties of the resulting colors, which tended to be slightly darker in color. The formula with silver nanoparticles synthesized in methanolic of patchouli leaf extract (AgMENPs) had the highest thermal stability compared to hydrogel films with silver nanoparticles synthesized in aqueous of patchouli leaf extract (AgAENPs). The hydrogel films can be safely used up to 200 °C. The antibacterial studies revealed that the films inhibited the growth of both Staphylococcus aureus and Staphylococcus epidermis, as determined by the disc diffusion method, with the best antibacterial activity being against Staphylococcus aureus. In conclusion, the hydrogel film F1, loaded with silver nanoparticles biosynthesized in aqueous of patchouli leave extract (AgAENPs) and light fraction of patchouli oil (LFoPO) performed the best activity against both Staphylococcus aureus and Staphylococcus epidermis.

Plasticizing effect of 1‐butyl‐3‐methylimidazolium bromide content on poly(vinyl alcohol)

AbstractPVA/IL composites were successfully prepared with an ionic liquid (IL), 1‐butyl‐3‐methylimidazolium bromide and poly(vinyl alcohol) (PVA). The plasticizing effect of IL on PVA was investigated using Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), X‐ray diffraction (XRD), thermogravimetric analysis (TGA) and melt flow index (MI) measurements. FTIR analysis indicated that the anion (Br−) of IL could form hydrogen bonds with the hydroxyl groups of PVA. With an increase of IL, –OH absorption peaks of PVA/IL composites shifted to higher wavenumbers. DSC analysis showed that both melt and crystallization temperatures of the PVA/IL composites decreased as IL content increased. XRD analysis showed that the degree of crystallinity of the PVA/IL composites had a decreasing trend with an increase of IL. TGA showed that IL could effectively improve the thermal stability of PVA. The thermal stability of the PVA/IL composites decreased gradually with increasing IL content, but was higher than that of PVA. Thermal processing window (ΔT) analysis indicated that the addition of IL could significantly broaden ΔT of the PVA/IL composites, and their ΔT values first remained basically unchanged and then increased slightly with an increase of IL. In addition, MI analysis presented that the melt processability of the PVA/IL composites was not improved with the addition of IL and it was gradually improved with increasing IL content. In this work, PVA/IL composites with wide ΔT and high melt flow properties were prepared, which will lay a solid foundation for the preparation of high‐performance PVA fibers by melt spinning. © 2022 Society of Industrial Chemistry.

Performance relative study of metal oxide nanoparticles on mechanical, thermal, and optical characteristics of gamma‐irradiated poly (vinyl alcohol) nanocomposites

Nanocomposites based on poly (vinyl alcohol) (PVA) filled with different types of nanometal oxides named MgO, Al2O3, and CuO were attained from an aqueous solution of PVA. PVA/nanometal oxide films were achieved by the solution casting procedure. The prepared nanocomposites were subjected to a gamma radiation dose at 50 kGy to study the impact of ionizing radiation on the various properties of the prepared samples. In this context, this work was mainly concerned with the differences in the behavior of various metal oxides, as well as the effect of ionizing radiation on the tensile strength (TS), elongation at break (E%), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X‐ray diffraction, and optical characteristics of the fabricated specimens. Furthermore, Fourier transform infrared (FTIR), SEM, and thermodynamic factors (Ea, ΔH, ΔG, and ΔS) were considered. FTIR and the suggested reaction mechanism supported that the hydroxyl groups of PVA have a really strong affinity to form charge‐transfer complexes with different nanometal oxides done chelation. In general, the interference of 0.1% of all studied nanometal oxides improved TS, thermal stability, melting temperature, and optical properties of PVA, whereas PVA/0.1 CuO was the best. Moreover, gamma radiation exposure enhanced the different properties of native PVA and displayed anisotropic behavior toward its nanocomposites.

Fabrication of electrospun Mondia whitei/PVA nanofibres: application in the removal of acidic drugs

Novel electrospun Mondia whitei/PVA blend nanofibres were fabricated for potential water treatment applications by blending a natural polymer extracted from Mondia whitei (MW) roots with poly (vinyl alcohol) (PVA). The fabricated nanofibres were shown to have a smooth and uniform morphology with an average diameter of 99 ± 0.025 nm. The FTIR, XPS, XRD, and TGA characterisation results indicated changes in functional groups, crystallinity, and thermal stability of the Mondia whitei/PVA blend nanofibres, as compared to the original material. This finding confirmed that the polymers interacted through hydrogen bonding of MW and hydroxyl groups of PVA. The performance of the fabricated nanofibres was investigated for the removal of acidic drugs from spiked water samples. Factors (concentration of acidic drugs, dosage of the nanofibers and contact time) which affect the removal efficiency of the nanofibres were optimised using ultrapure water. Using the nanofibres, 100% removal efficiency for acidic drugs (aspirin, ketoprofen, fenoprofen, diclofenac, and ibuprofen) was achieved. The removal efficiency of the influent wastewater was 76, 89, 97, 93 and 94% for aspirin, ketoprofen, fenoprofen, diclofenac and ibuprofen, respectively, while the removal efficiency of the effluent was 86, 96, 97, 97 and 95% for aspirin, ketoprofen, fenoprofen, diclofenac and ibuprofen, respectively.

Luminescent composite organohydrogels with Fe3+, pH, and glucose-dependent shape memory behavior accompanied with diverse fluorescence variation

It is quite urgent to develop a smart and high through-put confidential information storage, protection, and display platform based on the fluorescent hydrogels that could exhibit diverse fluorescent variation behavior during each stimulus-based shape memory and recovery process. Herein, it proposed an effective approach to develop a novel fluorescent composite gel with Fe3+, pH, and glucose-dependent diversity fluorescence variation and shape memory behavior. For this composite gel system, based on the reversible coordination interactions between Fe3+ and carboxylic acid groups of carboxymethyl cellulose (CMC), boric acid groups of carbon dots (CDs), and hydroxyl groups of PVA, it can stabilize and memorize the temporary shapes under the stimulus of Fe3+ and pH, respectively. Meanwhile, the fluorescence of the CDs within the gels can also exhibit diversity variation behaviors during each shape recovery process. Furthermore, the compositions of the composite gel were optimized to realize relatively high efficiency of shape recovery and fluorescence variation under each type of stimulus. In summary, this study presented a universal strategy for multi-shape memory hydrogels with diverse fluorescence variation properties which exhibited prominent prospective in the field of information encryption with high-level security.

Gel polymer dominated ion charging mechanisms within graphene nanochannels

Revealing microscopic real-time ion transport behavior is critically-important for understanding the charging mechanisms of polymer electrolytes. Herein polymer dominated ion charging mechanism of LiCl/polyvinyl alcohol (PVA) gel polymer electrolytes within graphene nanochannels is observed by combined electrochemical quartz crystal microbalance (EQCM) and molecule dynamics (MD) simulations. This is substantially different with the conventional aqueous electrolytes, demonstrating the dominated role of PVA polymer (including polymer-ion and polymer-electrode interactions) in mediating the charging mechanisms. Specifically, in-situ EQCM measurement reveals that –OH polar groups of PVA exhibit more significant hindrance to cations than anions, yielding the charging mechanisms from Li+ adsorption/desorption (at 0 wt % PVA) to Li+/Cl− ion exchange dominated transport (at 40 wt % PVA). Furthermore, ionic flux is quantitatively characterized based on the non-equilibrium thermodynamics, and the charging resistance is revealed via combining constant potential method and equivalent electric circuits. More importantly, increasing PVA concentration remarkably affects the thermodynamic properties (e.g., dielectric property, angle distribution and number density), while almost identical capacitance is recognized because of higher dielectric constant of PVA molecules. By solving Poisson equation, this is further interpreted and invalidated by quantifying the contributions of ions, solvents and PVA molecules to the electric potentials.

Ionic conductivity enhancement for PVA/ 20wt.% CuSO4 gel polymer electrolyte by using glycerin

Gel polymer electrolyte based on PVA+20wt.%CuSO4 was plasticized with (1,2 and 3) mL glycerin and prepared by casting method. Ionic conductivity for gel electrolytes enhancement occurs primarily as a result of increased carrier concentration and secondarily as a result of increased carrier mobility. Using X-ray diffraction (XRD) characterization, they observed that the glycerin-free electrolyte matrix has a regular arrangement with the crystalline phase. After adding glycerin, the observed orderly organization and crystalline phase fully transformed to amorphous. Fourier transform infrared spectroscopy (FTIR) result shows that the stretching vibration region of the O–H at 3261 cm−1 The hydrogen bonds formed by the hydroxyl groups of both PVA and glycerol structures explanation for the hydrophilic behavior of glycerol and the increased area. The new intense and strong peak that emerged at 2359.62 cm-1 is related to the aromatic Cu-O stretching of the salt CuSO4, The interaction of the PVA with the electrolyte elements increases its intensity with increasing glycerol.

Polyvinyl alcohol/corn starch/castor oil hydrogel films, loaded with silver nanoparticles biosynthesized in Mentha piperita leaves’ extract

ObjectivesHydrogel films were prepared from Polyvinyl alcohol [PVA], Corn starch [CS], Castor oil [CO] and silver nanoparticles [SNP], biosynthesized in leaves’ extract of locally grown Mentha piperita L. (Family, Labiatae) for prospective application as wound dressings. MethodsBoth aqueous [AME] and methanolic [MME] extracts of Mentha piperita leaves were used for phytochemical synthesis of SNP, that were later dispersed in hydrogel matrix by simple blending of the constituents (PVA, CS, CO, AME/MME and SNP) and crosslinking with glutaraldehyde. ResultsThe hydrogel films were flexible and biodegradable. The structure analysis by FTIR suggested hydrogen bonding between the functional groups of PVA, CS and CO in the films. SEM analysis revealed that SNP globules were distributed (10.02% and 12.57%) throughout the hydrogel matrices that were prepared from both AME and MME, respectively. The hydrogel films with MME showed higher thermal stability than those formed from AME due to uniform dispersion of small (size ≤70 nm) and unagglomerated SNP in the former. The hydrogel films can be safely used upto 200°C. The antibacterial studies exhibited that the films inhibited the growth of both S. aureus and P. aeruginosa, as investigated by disc diffusion method. ConclusionThe hydrogel films were prepared through ecofriendly and benign route, devoid of any toxic solvents, diluents, surfactants, stabilizers and can be employed as thermally stable, antibacterial and biodegradable films. The hydrogel films with MME showed better performance than AME films, for prospective application as wound dressings.

Hydroxyl crosslinking reinforced bagasse cellulose/polyvinyl alcohol composite films as biodegradable packaging

To improve the packaging applicability of cellulose-based film, cellulose/polyvinyl alcohol (Cel/PVA) composite films were prepared via crosslinking the hydroxyl groups (-OH) among cellulose and PVA as well as the dehydration/etherification between -OH of adjacent PVA chains. The structure and morphology, mechanical/barrier properties, water resistance, food preservation and degradation behavior in soil of the films were comprehensively characterized. The results indicated that the cellulose-based film (Cel/PVA-10-H) containing 10% PVA thermal-treated at 165 ℃ possessed the best overall performance, which was mainly attributed to the crosslinked structure formed by the hydroxyl groups of cellulose and PVA. The tensile strength (TS) and elongation at break (EB) reached 77.17 MPa and 9.96%, respectively, which were approximately 220% and 97% higher than those of cellulose/PVA blend film without crosslinking. Moreover, the mechanical properties and oxygen permeability (2.04 × 10−5 cm3 mm−1 d−1 atm−1) of Cel/PVA-10-H film were less sensitive to high humidity (RH ≥ 80%), indicating that the cellulose-based composite crosslinked film possessed excellent water resistance. The results from cherry preservation and degradation tests in soil demonstrated that the as-prepared films kept the freshness of the fruits well and possessed excellent biodegradability.