Polyvinyl Alcohol Composites Research Articles

A hybrid 3D-printed and electrospun bilayer pharmaceutical membrane based on polycaprolactone/chitosan/polyvinyl alcohol for wound healing applications

Skin injuries resulting from physical trauma pose significant health risks, necessitating advanced wound care solutions. This investigation introduces an innovative bilayer wound dressing composed of 3D-printed propolis-coated polycaprolactone (PCL/PP) and an electrospun composite of polyvinyl alcohol, chitosan, polycaprolactone, and diltiazem (PVA/CTS/PCL/DTZ). SEM analysis revealed a bilayer structure with 89.23 ± 51.47 % porosity and uniformly distributed nanofibers. The scaffold tensile strength, with pore sizes of 100, 300, and 500 μm, was comparable to native skin. However, smaller pore sizes reduced water vapor transmission from 4211.59 ± 168.53 to 2358.49 ± 203.63 g/m2. The incorporation of DTZ lowered the contact angle to 35.23 ± 3.65°, while the addition of PCL reduced the degradation rate and modulated the release of DTZ by approximately 50 %. Moreover, lower pH increased the degradation rate and decreased swelling. The inclusion of propolis enhanced antibacterial activity, and 10 % DTZ promoted the viability, proliferation, and migration of fibroblasts and adipose-derived stem cells. However, increasing DTZ concentration to 12 % reduced cell viability. In vivo tests on rats demonstrated effective wound healing and anti-inflammatory properties of the bilayer samples. Regarding the aforementioned results, the PCL/PP-PVA/CTS/PCL/DTZ (10 % w/w) bilayer wound dressing is a promising candidate for wound healing applications.

Development and characterization of highly conductive hybrid Moringa oleifera husk biocarbon and grape pulp cobalt oxide polyvinyl alcohol composites for microwave shielding

Development and characterization of highly conductive hybrid Moringa oleifera husk biocarbon and grape pulp cobalt oxide polyvinyl alcohol composites for microwave shielding

Developing flame retardant, smoke suppression and self-healing polyvinyl alcohol composites by dynamic reversible cross-linked chitosan-based macromolecule

With the increasing threat of white pollution to the public health and ecosystem, functional materials driven by green and sustainable biological macromolecule are attracting considerable attention. Inspired by the double-helix structure of DNA, a P–B–N ternary synergistic chitosan-based macromolecule (PBCS) was constructed to prepare flame retardant, smoke suppression and self-healing polyvinyl alcohol composite (PVA@PBCS) via dynamic reversible interactions. The limiting oxygen index value of PVA@PBCS increased from 19.6 % to 28.7 %, whereas the peak heat release rate and total heat release decreased by 47.04 % and 43.37 %, respectively. Besides, the peak smoke production rate and total smoke production of PVA@PBCS also decreased by 45.31 % and 54.98 %. With the presence of borate ester-based covalent and multiple hydrogen bonds, the tensile strength and elongation at break of PVA@PBCS increased by 19.50 % and 16.85 % compared to the control sample, and the healing efficiency for tensile strength and elongation at break was as high as 93.86 % and 90.57 %, respectively. This work developed an eco-friendly and effective scenario for fabricating flame retardant and smoke suppression PVA materials, stimulating the substantial potential of chitosan-based biomacromolecule and dynamic reversible cross-linked tactics in self-healing field.

Design and development of lignin nanobottles: Toward developing novel multifunctional nanocomposites

The design of lignin nanostructures, which leverages interfacial interactions to enhance colloidal network entanglement, holds promise for expanding their applications in polyvinyl alcohol (PVA) composites. Herein, a novel approach is proposed for fabricating lignin nanobottles (LNBs) using biomass-derived γ-butyrolactone (GBL) to create hollow interiors connected to a single surface opening. The resulting LNBs exhibit uniform sizes of approximately 108 nm with an opening diameter of 34.94 nm. Incorporating LNBs into PVA composites enhances mechanical properties significantly, with a tensile strength of 64.96 MPa and an elongation at break of 611.6 %. Moreover, the nanocomposite films demonstrate notable antibacterial effects, UV protection, and hydrophobicity. Introducing LNBs improves photothermal conversion capacity, achieving a temperature of 62.1 °C in just 150 s. Furthermore, a meticulously designed 3D solar evaporator demonstrates remarkable evaporation performance, achieving a rate of up to 1.89 kg m-2h−1 with an outstanding efficiency of 96.55 %. When exposed to 1 sunlight, the thermoelectric material generates an output voltage of 0.83 V, indicating considerable potential for energy generation. Overall, Incorporating LNBs enhances lignin’s effectiveness in materials and provides a novel approach to augment lignin’s photothermal properties, enabling broader applications in solar-driven evaporation and thermoelectric materials.

Characteristics of Cellulose Acetate Composite Membranes (Ca/Cs, Ca/Pva, Ca/Peg) As Cu(Ii) Metal Ion Filtration Membranes

Industrial development in Indonesia has caused increased pollution, including water pollution by heavy metals, one of which is the metal ion Cu(II). Cellulose acetate composite membranes have been widely used to overcome the problem of Cu(II) metal ion content in water, however, studies on the performance of cellulose acetate membranes with various types of chitosan, polyvinyl alcohol (PVA) and polyethylene glycol (PEG) composites have not been widely reported. This research aims to analyze the characteristics of cellulose acetate composite membranes with chitosan, PEG, and PVA using FTIR and SEM and to determine the performance of these cellulose acetate composite membranes in filtering Cu(II) metal from the resulting rejection values. The membrane was made using the phase inversion method and the composite membrane was made using the dip-coating method. The results of characterization using FTIR showed that there were no new peaks in all cellulose acetate composites, so there were only physical interactions in the composites. SEM analysis shows that the surface of the composite membrane is more irregular and the porosity increases. The performance of the composite membrane in filtering Cu(II) metal is better than the pure cellulose acetate membrane.

Electrochemical incorporation of PVA-ZnO composite on Screen printed carbon electrode as dopamine sensor

In this study, a composite of zinc oxide (ZnO) nanoparticles and polyvinyl alcohol (PVA) on a screen-printed carbon electrode (SPCE), termed SPCE/PVA/ZnO electrode, was utilized to develop an enhanced electrochemical sensor for dopamine (DA) detection. A novel method for synthesizing ZnO nanoparticles using almond gum at room temperature was introduced. X-Ray Diffraction (XRD) analysis confirmed the crystallinity of the ZnO nanoparticles. The SPCE/PVA/ZnO electrode was fabricated and characterized using Field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive X-ray Spectroscopy (EDX). Cyclic voltammetry was employed to measure DA, revealing a linear increase in the electrochemical oxidation signal of DA at the SPCE/PVA/ZnO composite from 100 to 600 μM. The sensor demonstrated a limit of detection of 0.1208 mM and a sensitivity of 0.01822 μAμM−1cm−2. The SPCE/PVA/ZnO sensor showed acceptable performance in evaluating dopamine in real sample study.

Phosphonitrile hybrid metal-polyphenol network: An effective strategy for developing functional PVA composites with flame retardancy, antibacterial and UV resistance

The white pollution caused by non-degradable plastics poses a serious threat to human society and the environment, thus developing biodegradable material is urgent. In this work, a novel phosphonitrile hybrid metal-polyphenol network was constructed and used for the preparation of flame retardant, UV resistant and antibacterial multifunctional polyvinyl alcohol composite (PVA@HCPD-Ag). The limiting oxygen index (LOI) value of PVA@HCPD-Ag was improved to 33.5%, while the peak heat release rate (PHRR) and total heat release (THR) decreased by 35.62% and 47.76%. Besides, the ultraviolet protection factor (UPF) value of PVA@HCPD-Ag was significantly improved from 4.63 of the original PVA to 482.79, while the tensile strength was increased by 10.23%. Furthermore, the inhibition efficacy of PVA@HCPD-Ag for E. coli and S. aureus was up to 98.12% and 99.99%. This work explored the synergistic flame retardant effect of in-situ reduced Ag0 and phosphonitrile crosslinked polyphenol network and proposed an advanced strategy for developing high value-added functionalized PVA materials.

Synthesis of flexible magneto‐electric polyvinyl alcohol composites using hybrid filler particles of carbon quantum dots and cobalt nano for electromagnetic interference shielding application

AbstractThe main objective of the study is to synthesis and characterization of flexible magneto‐electric Polyvinyl Alcohol (PVA) composites for Electromagnetic Interference (EMI) shielding applications, by incorporating carbon quantum dots extracted from lychee fruit husks and cobalt nanoparticles sourced from Plectranthus amboinicus. Comprehensive mechanical, dielectrical, magnetic, and shielding tests were conducted to assess the performance of these novel materials. The mechanical characteristics of the composites were assessed to gauge their flexibility and robustness. In this regard, PV4 displayed a substantial tensile strength of 68 MPa, while PV6 exhibited an enhanced shore‐D hardness rating of 47. PV6 demonstrates superior dielectric properties, including a higher dielectric constant and a lower loss tangent, which are crucial for optimizing EMI shielding efficiency. When it comes to magnetic characteristics such as magnetization, retentivity, and coercivity, the PV6 composite designation outperforms the other composites. Additionally, PV6 exhibits higher electromagnetic interference (EMI) shielding effectiveness, measuring at approximately 49.8 dB in the E band and 56.5 dB in the F band. Findings demonstrate that the integration of carbon quantum dots and cobalt nanoparticles into the matrix resulted in flexible composites with enhanced mechanical strength. The incorporation of cobalt contributed to notable magnetic properties, increasing the materials' magnetization and retentivity. The tests on electromagnetic interference (EMI) showed that the shielding effectiveness got improved. The composite materials were able to reduce interference from electromagnetic waves in the tested frequency ranges. These flexible magneto‐electric PVA composites, developed using sustainable sources such as lychee fruit husks and Plectranthus amboinicus, exhibit promising potential for EMI shielding applications in diverse industries, including telecommunications, aerospace, and electronics, where reliable interference control is essential for optimal performance and safety.Highlights Cobalt nanoparticles sourced from Plectranthus amboinicus. Carbon quantum dots are prepared from lychee fruit husks via controlled pyrolysis. High tensile strength PVA composites prepared. Highest dielectric constant of 8.2 achieved for composite PV6. Higher wave shielding up to 56.5 dB achieved in “E” band.

The impact of nanoparticle surface topography on the interfacial mechanical behavior and microstructure of polyvinyl alcohol composites

The interfacial mechanical strength between nanoparticle and matrix is one of the key factors affecting the mechanical properties of nanoparticulate-polymer composites. Based on the structural composition of a nanoscale iron particle/polyvinyl alcohol composite, this study employed molecular dynamics simulations to investigate the stress-response behavior and microstructural evolution of Fe/PVA/Fe interface models with different surface morphologies under both tensile and shear deformations. The results indicate that when the particle surfaces exhibit different rough structures, the interfacial tensile strength significantly increases with the absolute value of the interfacial binding energy. The order of tensile strength is Type-cube > Type-pyramid > Type-plane. Furthermore, during the shearing process, the protruding structures on the particle surfaces significantly hinder the deformation and unfolding of the matrix molecular chains. As the volume of the protruding structures increases, the interfacial shear strength decreases markedly. The research findings illuminate the mechanisms by which nanoparticle surface morphology at the microscopic molecular scale influences the mechanical properties of nanoparticle-polymer composite materials. These discoveries aid in selecting nanoparticle fillers that enhance the mechanical performance of polymer nanocomposites to a measurable extent.

Optimization of mass transfer-enhanced chlorine-resistant crosslinked PVA composite membranes for pervaporation desalination

Pervaporation (PV) is characterised by good hydrophilicity and antifouling properties. However, it is still unavoidable to need cleaning during long-term operation. Sodium hypochlorite (NaClO) is a commonly used purifying agent for organic pollutants, but it may cause damage to the polymer membrane. In this study, a grafting method was proposed to enhance the chlorine resistance and water permeability of membrane composite polyvinyl alcohol (PVA) pervaporation membrane. Modified PVA (SPVA) was prepared by grafting 5-sulfosalicylic acid (SSA) to improve the hydrophilicity of the membrane using the sulfonic acid group on SSA. SPVA-FA/PTFE composite membranes were prepared by using perfluoroglutaric acid (PFGA) as crosslinking agent to improve the chlorine resistance of the membranes by utilising the C-F chain contained therein. The water flux was 120.38 ± 1.72 kg/(m2·h), which was 84.2 % higher than that before grafting, when tested at 70 °C and 3.5 wt% NaCl. The chlorine resistance of SPVA-PFGA/PTFE composite membrane was tested in 2000 ppm (pH = 12) NaClO solution for 480 h, and the salt rejection remained above 99.93 %. When desalinating 20 wt% NaCl at 70 °C, the water flux of SPVA-PFGA/PTFE membrane is 51.95 ± 0.6 kg/(m2·h), which has the potential to treat high concentration brine.

Preclinical evaluation of the individualized approach for chronic non-healing wounds management

Chronic non‑healing wounds (CNHW) are very common and often incorrectly treated, the morbidity and associated costs of chronic wounds management highlight the need to implement wound prevention and treatment concepts. Objective — to evaluate the possibility of different metal nanooxide polymer nanofilms use for CNHW’ local treatment. Materials and methods. The study design is based on evaluation of various types of dressing materials considering their option for use in CNHW local treatment. Samples of biodegradable polymer films (with an optimal composition of gelatin, polyvinyl alcohol, lactic acid, glycerin and distilled water) saturated with nanoparticles of several oxides with expected antibacterial and pro‑regenerative feature — nZnO, nMgO in concentrations of 1%, 5%, and 10% were used in the study of antimicrobial action and substance release profiling. Quarterly ammonium antiseptic decamethoxin 0.02% was used for control. Results. Obtained data shows that polymer based biodegradable films incorporating optimal component composition (gelatin, polyvinyl alcohol, lactic acid and glycerin) enriched with 5% and 10% zinc nanooxide have potent antimicrobial activity against both gram‑positive and gram‑negative microorganisms, the most common causative agents of CNHW’s. The ion release capacity analysis showed that the Zinc impregnated wound‑healing biodegradable polymer film gradually releases the active substance in a time dependent manner, and the nano‑sized particles of nanoZinc oxide are released from the polymer composition faster than ordinary zinc oxide. Conclusions. Complex natural biodegradable polymer based nanofilms are composite materials impregnated with metal nanooxides showing high potential in local treatment of chronic non‑healing wounds. Polymer film with 5% nanoZnO showed up to the 58% higher antimicrobial activity, comparable or exceeding the one of quarterly ammonium compound decamethoxin. Furthermore, nanoZnO impregnated polymer films compared to standard ZnO impregnated polymer films showed up to 63.2% faster substance release profile with rapid and more unified curve.

Terahertz-based optoelectronic properties of ZnS quantum dot-polymer composites: For device applications

Terahertz (THz) technology integration with nanomaterials is receiving excellent attention for next-generation applications, including enhanced imaging and communication. The excellent optical properties in THz domain can lead to preparation of low-cost CMOS camera which can convert THz radiation into optical signal in very efficient manner. In the present study, we have studied the properties of Zinc Sulfide quantum dots (ZnS QDs) embedded with Polyvinyl Alcohol (PVA) composites films using THz Signal at room temperature. The optical characterizations such as refractive index, absorption coefficients and dielectric constants of these samples were measured in the 0.1–2.0 THz range. Additionally, optical impedance, surface roughness, and reflection coefficient in TE and TM mode between 0.1 and 2.0 THz range were determined for these samples based on surface roughness-based reflection and scattering properties. The surface roughness factor was used to measure the optical impedance of the ZnS QDs based polymer films. The measured values of the absorption coefficient at 266 nm are compared with THz radiation, and the refractive indices of these samples range from 1.75 to 2.0. Finally, these samples were subjected to UV light excitation (λexe = 266 nm) of 0.15 ns duration and 400 nm for the fluorescence and corresponding life time measurements. We observed two numbers of fluorescence lines in nanosecond based excited domain whereas 400 nm excitation-based fluorescence life time lies between 13.8–11.39 ns range along with shift in fluorescence lines between 538.7 to 560.7 nm, respectively.

Recent Advances in the Fabrication and Performance Optimization of Polyvinyl Alcohol Based Vascular Grafts.

Cardiovascular disease is one of the diseases with the highest morbidity and mortality rates worldwide, and coronary artery bypass grafting (CABG) is a fast and effective treatment. More researchers are investigating in artificial blood vessels due to the limitations of autologous blood vessels. Despite the availability of large-diameter vascular grafts (Ø>6mm) for clinical use, small-diameter vascular grafts (Ø<6mm) have been a challenge for researchers to overcome in recent years. Vascular grafts made of polyvinyl alcohol (PVA) and PVA-based composites have excellent biocompatibility and mechanical characteristics. In order to gain a clearer and more specific understanding of the progress in PVA vascular graft research, particularly regarding the preparation methods, principles, and functionality of PVA vascular graft, this article discusses the mechanical properties, biocompatibility, blood compatibility, and other properties of PVA vascular graft prepared or enhanced with different blends using various techniques that mimic natural blood vessels. The findings reveal the feasibility and promising potential of PVA or PVA-based composite materials as vascular grafts.

Structural, Optical, and Morphological Study of Manganese Substituted Cobalt Ferrite and Its Effect on the Magnetic and Dielectric Properties of PVA Composites

Nanopowders of Mn-substituted CoFe2O4 were prepared in different proportions using the sol-gel auto-combustion method and were structurally and morphologically studied. In another step, composites based on polyvinyl alcohol (PVA) with Mn-substituted CoFe2O4 fillers were prepared, and the effect of the Mn-substituted CoFe2O4 on the optical, magnetic, and dielectric properties was studied. X-ray analysis revealed the formation of polycrystalline Mn-substituted CoFe2O4. The results showed a decrease in the lattice constant with Mn2+ substituted and incorporated into the crystal structure of CoFe2O4. The Fourier confirmed the spinel structure of the Mn-substituted CoFe2O4 transform infrared spectrum where absorption bands appeared at 569–561 and 446–407 cm-1, which are attributed to tetrahedral and octahedral groups. The magnetic properties were affected when Mn ions were substituted with CoFe2O4, as shown by the results of VSM. It was observed that the saturation magnetization, remnant magnetization, and coercivity decreased with increasing Mn content. The dielectric constant and loss tangent of PVA/MnxCo1−xFe2O4 were also studied. The difference in the diameters of the substituted and host ions causes the dielectric constant to increase following the substitution of Mn ions.

Mechanical, Optical, and Thermal Properties of SnS2-Filled PVA Composites

The effects of tin disulfide (SnS2) addition on the mechanical, thermal, and optical characteristics of polyvinyl alcohol (PVA) were determined in this study. The solvent-casting approach was used to create composite films with varying SnS2 weight ratios. Mechanical testing revealed that the addition of SnS2 raised the tensile strength (TS) of the virgin PVA from 32.10 MPa to 47.50 MPa, while the elongation at break (EB) increased from 78.40% to 108.80%. Optical investigations revealed that PVA and SnS2 had intermolecular interactions. Furthermore, the contribution of SnS2 resulted in a drop in energy bandwidth from 5.310 eV to 4.821 eV. Thermal investigations revealed that PVA/SnS2 had greater stability than the virgin polymer. Given the data obtained, it was obtained that the addition of SnS2 simultaneously enhanced the mechanical, thermal, and optical properties of PVA.

Effects of Vancomycin/Tobramycin-Doped Ceramic Composite (Polyvinyl Alcohol Composite–Vancomycin/Tobramycin–Polymeric Dicalcium Phosphate Dihydrate) in a Rat Femur Model Implanted With Contaminated Porous Titanium Cylinders

BackgroundPeriprosthetic joint infection (PJI) remains common and problematic. We hypothesized that using a bioceramic that provided rapid release of the antibiotics (vancomycin [VAN] or VAN and tobramycin [VAN and TOB]) from a polyvinyl-alcohol-composite (PVA) combined with a delayed and sustained antibiotic release from polymeric-dicalcium-phosphate-dihydrate (PDCPD) ceramic would inhibit S. aureus-associated implant infections. MethodsA total of 50 male Sprague Dawley rats were randomly divided into 5 groups—I: negative control; II: bacteria only; III: bacteria + saline wash; IV: bacteria + PVA-VAN-PDCPD, and V: bacteria + PVA-VAN-TOB-PDCPD. A porous titanium (Ti) implant was press-fit into the rat knee. S. aureus-containing broth was added into the joint space creating a PJI. After 1 week, the joints from groups III to V were washed with saline and the fluid collected for bacterial quantification. This was followed by saline irrigation treatment (groups III to V) and application of the antibiotic-loaded PVA-PDCPD bioceramic (groups IV and V). On day 21, joint fluid was collected, and the implants harvested for bacterial quantification. ResultsNo bacteria were isolated from the negative control (group I). The positive control (group II) was positive on both days 7 and 21. Bacteria were still present on day 21 in the fluid and implant in group III. Groups (IV and V) showed a decrease in the bacterial burden in the fluid and implant on day 21. There were significant differences in bacteria levels in the collected wash fluid and on the implant at day 21 between the saline wash (group III) and treatment groups (IV and V). ConclusionsIn this animal model of acute periprosthetic infection, treatment with PVA-VAN-PDCPD and PVA-VAN/TOB-PDCPD reduced bacterial load in the infected joint and the infected Ti implant. Application of PVA-VAN-PDCPD and/or PVA-VAN/TOB-PDCPD after saline irrigation could be used as an addition to the treatment of PJI.

Amine functionalised graphene embedded polyvinyl alcohol (PVA) and PVA-chitosan hydrogel composites

A novel amine-functionalized graphene oxide (AFG) doped polyvinyl alcohol (PVA)/chitosan (PVA-Ch) composite film was developed using an eco-synthesis approach, eliminating the need for halogenated compounds. The resulting AFG-doped PVA/Chitosan (PVA-Ch/AFG) polymer film exhibited promising properties for controlled delivery and biosensing applications. The investigation included assessing the swelling behaviour, dissolution percent, gel fraction, and mechanical properties of the polymer film. The swelling characteristics of PVA-Ch and PVA-Ch/AFG were found to be pH and temperature-dependent across various pH ranges (3, 5, 7, and 9). Interestingly, PVA-Ch/AFG demonstrated a stable swelling pattern at pH 5 and 7, unaffected by changes in chitosan concentration, indicating enhanced stability compared to PVA-Ch. The study also explored the use of PVA-Ch/AFG in a drug delivery system, revealing controlled release of the model antibiotic amphicillin, emphasizing its potential in medical applications. Furthermore, the eco-friendly synthesis route underscored the safety of PVA-Ch/AFG for use in food and medical applications. Biocompatibility assessments, including biodegradability studies and cytotoxicity tests on fibroblasts (3T3 cells), confirmed the safety profile of PVA-Ch/AFG. In conclusion, the study suggests that PVA-Ch/AFG holds promise for bio-sensing applications, offering a flexible and colorimetric platform capable of encapsulating, adsorbing, and desorbing biomolecules such as drugs and sensing compounds.

Melt-processable polyvinyl alcohol/lignin composites with improved strength via synergistic plasticization of lignin

The characteristics of multi-hydroxyl structure and strong hydrogen bonding in polyvinyl alcohol (PVA) make its melting point close to its decomposition temperature, causing melt-processing difficulty. In this work, following the plasticization of small-molecule primary plasticizer acetamide, lignin was demonstrated as a green secondary plasticizer in realizing the melt processing and simultaneous reinforcement of PVA. During the plasticization process, lignin was able to combine with the hydroxyl groups of PVA, so as to destroy the hydrogen bonds and regularity of the PVA chains. The synergistic plasticization effect of lignin dramatically reduced the melting point of PVA from 185 °C to 151 °C. The thermal processing window of PVA composites was expanded from 50 °C to roughly 80 °C after introducing lignin. In contrast to acetamide, the addition of lignin significantly increased the tensile strength and Young's modulus of the composites to 71 MPa and 1.34 GPa, respectively. Meanwhile, lignin helped to hinder the migration of acetamide via hydrogen bonds. With the addition of lignin, the composites also displayed enhanced hydrophobicity and excellent UV shielding performance. The strategy of synergistic plasticization of lignin provides a feasible basis for the practical application of lignin in melt-processable PVA materials with good comprehensive properties.

Biocompatible neem gum-modified polyvinyl alcohol composite as dielectric material for flexible energy devices

In our pursuit of a flexible energy storage solution, we have developed biocompatible (bc)-NG/PVA composite polymers by combining neem tree gum (NG) with polyvinyl alcohol (PVA). This innovative bio-inspired approach harnesses NG's unique properties for both the bio-electrolyte and bio-electrode components. The resulting bc-NG/PVA composites exhibit superior dielectric strength and versatility, surpassing traditional inorganic ceramic dielectrics in advanced electronics and pulsed power systems. Our study investigates the dielectric characteristics, conductivities, electric modulus, and impedance parameters of Pure PVA and NG-doped PVA composites. Adding 5 % NG to PVA significantly boosts its conductivity from 10−8 S cm−1 to 10−4 S cm−1, while the dielectric constant of PVA/5 % NG composite jumps to 104.5 compared to pure PVA. These improvements position the composite films of 5 % NG added PVA as promising materials for diverse applications. The heightened performance of these NG-blended PVA composite materials underscores their potential as a valuable resource for flexible energy storage solutions.

Denitrification enhanced by composite carbon sources in AAO-biofilter: Efficiency and metagenomics research

Nitrogen removal from domestic sewage is usually limited by insufficient carbon source and electron donor. An economical solid carbon source was developed by composition of polyvinyl alcohol, sodium alginate, and corncob, which was utilized as external carbon source in the anaerobic anoxic oxic (AAO)-biofilter for the treatment of low carbon-to-nitrogen ratio domestic sewage, and the nitrogen removal was remarkably improved from 63.2% to 96.5%. Furthermore, the effluent chemical oxygen demand maintained at 35 mg/L or even lower, and the total nitrogen was reduced to less than 2 mg/L. Metagenomic analysis demonstrated that the microbial communities responsible for potential denitrification and organic matter degradation in both AAO and the biofilter reactors were mainly composed of Proteobacteria and Bacteroides, respectively. The solid carbon source addition resulted in relatively high abundance of functional enzymes responsible for NO3−-N to NO2−-N conversion in both AAO and the biofilter reactors, thus enabled stable reaction. The carbon source addition during glycolysis primarily led to the increase of genes associated with the metabolic conversion of fructose 1.6P2 to glycerol-3P The reactor maintained high abundance of genes related to the tricarboxylic acid cycle, and then guaranteed efficient carbon metabolism. The results indicate that the composite carbon source is feasible for denitrification enhancement of AAO-biofilter, which contribute to the theoretical foundation for practical nitrogen removal application.