This review highlights the performance enhancement of polyvinyl alcohol(PVA)composites through the incorporation of nanofillers,focusing on mechanical,thermal,electrical and piezoelectric improvements.It examines bio-...This review highlights the performance enhancement of polyvinyl alcohol(PVA)composites through the incorporation of nanofillers,focusing on mechanical,thermal,electrical and piezoelectric improvements.It examines bio-based fillers such as nanocellulose cellulose nanofibrils(CNF)and cellulose nanocrystals(CNC),and carbon-based fillers like graphene nanoplatelets(GNP)and carbon nanotubes(CNT).CNF and CNC increase tensile strength by up to 40%and 17.9%,respectively,due to their ability to reinforce polymer networks.CNC also improves thermal stability,raising degradation temperatures to approximately 327℃through enhanced hydrogen bonding.Electrical and piezoelectric properties are significantly improved,with dielectric behaviour enhanced by up to 107%and open-circuit voltage reaching 25.6 V,suitable for energy harvesting.GNP and CNT contribute by forming conductive networks within the PVA matrix,enabling superior electrical conductivity and consistent piezoresistive responses under strain.These characteristics make such composites ideal for applications in flexible electronics,sensors,structural health monitoring and other advanced fields.This synthesis of experimental results and critical insights underscores the broad utility and future potential of nanofillerenhanced PVA composites across aerospace,automotive,healthcare,and defence sectors.展开更多
Recycling plastic waste into triboelectric nanogenerators(TENGs)presents a sustainable approach to energy harvesting,self-powered sensing,and environmental remediation.This study investigates the recycling of polyviny...Recycling plastic waste into triboelectric nanogenerators(TENGs)presents a sustainable approach to energy harvesting,self-powered sensing,and environmental remediation.This study investigates the recycling of polyvinyl chloride(PVC)pipe waste polymers into nanofibers(NFs)optimized for TENG applications.We focused on optimizing the morphology of recycled PVC polymer to NFs and enhancing their piezoelectric properties by incorporating ZnO nanoparticles(NPs).The optimized PVC/0.5 wt%ZnO NFs were tested with Nylon-6 NFs,and copper(Cu)electrodes.The Nylon-6 NFs exhibited a power density of 726.3μWcm^(-2)—1.13 times higher than Cu and maintained 90%stability after 172800 cycles,successfully powering various colored LEDs.Additionally,a 3D-designed device was developed to harvest energy from biomechanical movements such as finger tapping,hand tapping,and foot pressing,making it suitable for wearable energy harvesting,automatic switches,and invisible sensors in surveillance systems.This study demonstrates that recycling polymers for TENG devices can effectively address energy,sensor,and environmental challenges.展开更多
Cerium oxide(CeO_(2)) has attracted much attention in recent years owing to its reversible switch ability in Ce^(3+)/Ce^(4+)redox to produce improved antioxidation properties for biomedical applications.Here,we report...Cerium oxide(CeO_(2)) has attracted much attention in recent years owing to its reversible switch ability in Ce^(3+)/Ce^(4+)redox to produce improved antioxidation properties for biomedical applications.Here,we report to embed the CeO_(2)nanospheres into the organic polymer network using electrostatic spinning technology to prepare polyvinyl alcohol(PVA)-encapsulated CeO_(2)nanospheres composite nanofibrous membranes(PVA-CeO_(2)) for the first time,which is beneficial to improving the dispersion and biocompatibility of CeO_(2)nanosphere without altering the original antioxidant properties of CeO_(2).Detailed characterization of the as-prepared composite nanofibrous membranes reveals that CeO_(2)was successfully introduced into the PVA fibers with strong interactions,thus enhancing the thermal stability and fracture toughness of the nanoifbers.As a result,PVA-CeO_(2)exhibits superior UV shielding performance,antioxidant performance and bacteriostatic performance.Meaningfully,PVA-CeO_(2)has strong absorbance in both UVA and UVB bands when the CeO_(2)concentration in the nanoifber membrane reaches 1.5 wt%,and shows an excellent scavenging effect on the 2,2-diphenyl-1-picrylhydrazyl(DPPH)radicals with a scavenging rate of 86.52%.Moreover,the Kirby-Bauer(K-B) method of agar diffusion test further confirms that PVA-CeO_(2)has antimicrobial ability against three types of representative strains,including Gram-positive bacteria(Staphylococcus aureus),Gram-negative bacteria(Escherichia coli) and fungi(Candida albicans).Importantly,no obvious cytotoxicity is observed for PVA-CeO_(2)even though the amount of embedded CeO_(2)nanosphere reaches as high as 1.5 wt%.This study reveals new avenues for improving the future smart design of CeO_(2)-based nanoifber membrane composite materials for biological antioxidants.展开更多
Chalcopyrite is often intergrown with talc,which,after grinding,forms ultrafine particles(<10μm)that readily coat chalcopyrite surfaces,hindering flotation and causing significant losses in tailings.This study eva...Chalcopyrite is often intergrown with talc,which,after grinding,forms ultrafine particles(<10μm)that readily coat chalcopyrite surfaces,hindering flotation and causing significant losses in tailings.This study evaluates polyvinyl acetate(PVAc),a thermoplastic polymer,as a selective flocculant to enhance reverse flot ation separation of chalcopyrite from ultrafine talc.Flotation tests showed that at a PVAc dosage of 40 mg/L,talc can be effectively and selectively removed,enabling efficient separation.Laser particle size analysis and scanning electron microscopy-energy dispersive spectrometry(SEM-EDS)confirmed that PVAc promotes selective talc aggregation without affecting chalcopyrite.X-ray photoelectron spectroscopy(XPS)and density functional theory(DFT)calculations revealed that hydrogen bonding between PVAc ester groups and surface hydroxyls on talc drives the flocculation,while chalcopyrite lacks suitable binding sites.PVAc adsorption also enhances talc hydrophobicity.Furthermore,particle-bubble coverage angle measurements and extended Derjaguin-Landau-Verwey-Overbeek(DLVO)theory theoretical calculations demonstrated that PVAc-induced flocculation increases attractive interactions between talc and bubbles,shifting the total interaction energy from repulsive to attractive and promoting bubble-particle attachment.This study clarifies the selective adsorption and flocculation mechanisms of PVAc and reveals the coupling of flocculation and flotation of ultrafine talc from a particle-bubble capture perspective,while expanding the potential of ester-based polymers for ultrafine mineral recovery.展开更多
Polyvinyl chloride(PVC)is one of the most widely used plastic materials worldwide,particularly in long-life applications such as construction materials.However,recycling options for PVC waste remain limited,as convent...Polyvinyl chloride(PVC)is one of the most widely used plastic materials worldwide,particularly in long-life applications such as construction materials.However,recycling options for PVC waste remain limited,as conventional methods often degrade material quality or generate environmentally hazardous byproducts.In this study,we demonstrate an efficient process to convert PVC into new polymers with variable aromatic groups,using triethylsilane as the reductant in different solvents.This approach enables the production of polymers analogous to functionalized polyethylene(PE),which are typically challenging to obtain through conventional copolymerization or direct post-modification of C-H bonds in PE.The resulting polymers exhibit tunable thermal and mechanical properties depending on the introduced aromatic groups,which not only enhance the sustainable valorization of PVC waste,but also provide an opportunity for the synthesis of new functionalized polymers.展开更多
In this study,we proposed a novel and efficient way to strengthen polyvinyl alcohol(PVA)fiber using graphene quantum dots(GQDs).PVA molecular chains were grafted onto the surface of GQDs through Friedel-Crafts alkylat...In this study,we proposed a novel and efficient way to strengthen polyvinyl alcohol(PVA)fiber using graphene quantum dots(GQDs).PVA molecular chains were grafted onto the surface of GQDs through Friedel-Crafts alkylation reaction to obtain functionalized GQDs(f-GQDs),and PVA/f-GQDs composite fiber was successfully prepared by wet spinning and post-treatment.The tensile strength and Young's modulus of the composite fiber reached up to 1229.24 MPa and 35.36 GPa which were approximately twice and 4 times those of the pure PVA fiber,respectively.Moreover,the composite fiber was demonstrated excellent resistance to solvents.In addition,the PVA/f-GQDs composite fiber showed intense and uniform cyan fluorescence,meanwhile,it could maintain stable solid-state fluorescence in acid and alkali solutions and particularly after long-term immersion in water(1 month).This study proposes a promising route for obtaining high-performance conventional fibers with some new functions.展开更多
The purpose of this research work is to determine the removal efficiency of Cu^(2+)and Pb^(2+)ions using polyvinyl alcohol/neem leaf extract/chitosan(PVA/NLE/CS)composite films as adsorbent materials from an aqueous m...The purpose of this research work is to determine the removal efficiency of Cu^(2+)and Pb^(2+)ions using polyvinyl alcohol/neem leaf extract/chitosan(PVA/NLE/CS)composite films as adsorbent materials from an aqueous medium,with respect to pH,contact time,and adsorbent dosage.The synthesized composite material was characterized using Fourier Transform Infrared(FTIR)spectroscopy,thermogravimetric analysis-Derivative Thermogravimetry(TGA-DTG),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),and scanning electron microscopy-Energy Dispersive X-ray Spectroscopy(SEM-EDX).The antibacterial activity and swelling response of the material were studied using suitable methodologies.The FTIR study confirmed the interactions among PVA,chitosan,and neem leaf extract.The TGA data reveal the excellent thermal stability of the developed composite films.The SEM micrograph indicates a homogeneous phase morphology with good compatibility among chitosan,the monomer,and the leaf extract.The antibacterial study revealed that the prepared PVA/NLE/CS films exhibit improved antibacterial activity against bacterial growth.It was found that at pH 6.0,the adsorption capacity for both toxic metal ions is maximum,and decreases with a further rise in pH.At this pH,the adsorption capacity of PVA/NLE/CS films increases with a gradual increase in adsorbent dosage,and at a specific pH,the adsorption capacity for Cu^(2+)is greater than that for Pb^(2+).The adsorption efficiency is a function of contact time and was found to be maximal at 180 min.Hence,the developed composite material is effective for the removal of metal ions from wastewater.展开更多
The current quality standard for polyvinyl alcohol eye drops lacks an impurity assessment,despite the potential impact of raw material impurities on product safety.To strengthen quality control and ensure drug safety,...The current quality standard for polyvinyl alcohol eye drops lacks an impurity assessment,despite the potential impact of raw material impurities on product safety.To strengthen quality control and ensure drug safety,an investigation into the impurity profile of the formulation was conducted,and an HPLC-UV method was developed for impurity quantification.The method validation was performed using an H-type cation exchange column.A total of 116 batches of polyvinyl alcohol eye drops from four manufacturers and two batches of the innovator drug were analyzed.Formic acid was detected exclusively in 0.4 mL samples from Company A and the innovator drug,with concentrations below 0.002%in both cases.Acetic acid was identified in samples from all manufacturers,with levels not exceeding 0.1%.The method demonstrated high specificity and sensitivity,making it well-suited for the quantification of formic and acetic acids in polyvinyl alcohol eye drops.The presence of formic acid was attributed to excipients,whereas acetic acid originated from raw materials and was further generated during pH adjustment in manufacturing.Although the overall impurity levels were low and posed minimal risk to drug safety,manufacturers should remain vigilant regarding impurity control to maintain product quality.展开更多
Polyvinyl alcohol (PVA) is a water-soluble polymer material, which has excellent mechanical properties, high strength, good stretchability and certain antibacterial ability, and is widely used in the fields of archite...Polyvinyl alcohol (PVA) is a water-soluble polymer material, which has excellent mechanical properties, high strength, good stretchability and certain antibacterial ability, and is widely used in the fields of architecture, medical treatment, textile and so on. This paper briefly introduces the preparation methods of polyvinyl alcohol, mainly focusing on the application research progress of polyvinyl alcohol. By summarizing the application of polyvinyl alcohol fiber, polyvinyl alcohol film and polyvinyl alcohol adhesive in various industries, the development of polyvinyl alcohol industry is further prospected.展开更多
[Objective] The aim of this study was to discuss the optimizing preparation conditions of polyvinyl alcohol(PVA)hollow microsphere and its application in the production of slow-release urea fertilizer.[Method]PVA holl...[Objective] The aim of this study was to discuss the optimizing preparation conditions of polyvinyl alcohol(PVA)hollow microsphere and its application in the production of slow-release urea fertilizer.[Method]PVA hollow microsphere was prepared by the emulsion chemical cross-linking method,while its composition,morphology and particle size was analyzed by technologies of FT-IR,SEM and TEM respectively.Thus,factors such as rate of emulsified speed,crosslink temperature and linking agent amount with effects on morphology and particle size of hollow microsphere were also discussed in this study.Furthermore,based on the optimizing preparation conditions,PVA fertilizer carrier microsphere was prepared by coating urea to investigate its sustained release effect on urea.[Result]The optimizing preparation conditions of polyvinyl alcohol(PVA)hollow microsphere were as follows:rate of emulsified speed 6 000 r/min,crosslink temperature 35 ℃ and linking agent amount 25 ml.PVA fertilizer carrier microsphere had significant sustained release effect on urea,and the optimal cross-linking time was 3 hours.[Conclusion]This study provides theoretical basis for the development of new slow-release fertilizer.展开更多
A novel technology of preparation of felt-metal supported modified polyvinyl alcohol（PVA） ultrafiltration（UF） membrane was invented, which could avoid the blockage of the holes of support layer and the leakage of ...A novel technology of preparation of felt-metal supported modified polyvinyl alcohol（PVA） ultrafiltration（UF） membrane was invented, which could avoid the blockage of the holes of support layer and the leakage of the casting solution through the holes of support layer. Felt-metal supported ferric sulfate modified PVA composite UF membranes were prepared by the innovative technology. The results show that the composite membranes are used to treat 1 000 mg/L oil/water emulsion at trans-membrane pressure from 0.25 to 0.45 MPa, the permeate flux is from 36 to 52 L/（m2·h）, and the retention of chemical oxygen demand（COD） is over 92%. The composite membrane resistance increases with the increase of trans-naembrane pressure.展开更多
Synthetic wood adhesives, consisting of urea-formaldehyde resins (UF), phenol-formaldehyde resins (PF), melamine-formaldehyde resins (MF), and polyurethane resins, are widely used. For UF and MF, most investigations a...Synthetic wood adhesives, consisting of urea-formaldehyde resins (UF), phenol-formaldehyde resins (PF), melamine-formaldehyde resins (MF), and polyurethane resins, are widely used. For UF and MF, most investigations are concerned with reducing free formaldehyde content;for PF, most studies focused on finding new alternative chemicals to replace phenol. These adhesives come under the Carcinogenic, Mutagenic, and Reprotoxic chemicals (CMR) category. Due to global energy issues and dependency on petroleum sources, the focus has shifted to look for alternative and renewable raw material sources for wood adhesives. Conventionally available wood adhesives are polyvinyl alcohol (PVA) stabilized, with drawbacks like poor water resistance, poor heat resistance, low-temperature workability, and it’s based on petroleum resources. Polyvinyl acetate (PVAc) is non-resistant to moisture polymer, and if such adhesive joints are exploited in a moist environment, its strength substantially decreases. Sufficiently moisture-resistant adhesive joints are obtained by modifying PVAc dispersion with special compounds like reactive comonomer, Silanes, and modified PVA. To improve the workability at low temperature, Vinyl acetate (VAc) is copolymerized with specific comonomers like butyl acetate without affecting the performance properties. Here, we aim to present an overview of the research trend of PVAc-based adhesives in the wood industry. The review summarizes the current state of research PVAc-based adhesives.展开更多
Polyvinylidene fluoride （PVDF） hollow fiber membranes prepared from spinning solutions with different polyvinyl pyrrolidone （PVP） contents （1% and 5%） at different extrusion rates were obtained by wet/dry phase ...Polyvinylidene fluoride （PVDF） hollow fiber membranes prepared from spinning solutions with different polyvinyl pyrrolidone （PVP） contents （1% and 5%） at different extrusion rates were obtained by wet/dry phase process keeping all other spinning parameters constant. In spinning these PVDF hollow fibers, dimethylacetamide （DMAc） and PVP were used as a solvent and an additive, respectively. Water was used as the inner coagulant. Dimethylformamide （DMF） and water （30/70） were used as the external coagulant. The performances of membranes were characterized in terms of water flux, solute rejection for the wet membranes. The structure and morphology of PVDF hollow fiber were examined by BET adsorption, dry/wet weight method and scanning electron microscopy （SEM）. It is found that the increase in PVP content and extrusion rate of spinning solution can result in the increase of water flux and decrease of solute rejection. The improvements of interconnected porous structure and pore size are induced by shear-thinning behavior of spinning solution at high extrusion rates, which could result in the increase of water flux of hollow fiber membranes. The increase of extrusion rate also leads to the increase of membrane thickness due to the recovery effect of elastic property of polymer chains.展开更多
Al<sub>2</sub>O<sub>3</sub>/PVFM/Al<sub>2</sub>O<sub>3</sub> trilayer membranes are prepared by means of simple coating of PVA-Al<sub>2</sub>O<sub>3<...Al<sub>2</sub>O<sub>3</sub>/PVFM/Al<sub>2</sub>O<sub>3</sub> trilayer membranes are prepared by means of simple coating of PVA-Al<sub>2</sub>O<sub>3</sub> solution onto both sides of PVFM thin membranes, which is prepared via phase inversion method. The characteristics of the trilayer membranes and gel polymer electrolytes are investigated using FESEM, tensile testing apparatus, thermal shrinkage test, EIS and charge-discharge test. When inorganic Al<sub>2</sub>O<sub>3</sub> particles are used to coat the PVFM membrane, drawbacks associated with gel-type membranes, namely, poor mechanical strength and thermal stability are greatly improved. Lithium ion cell with the Al<sub>2</sub>O<sub>3</sub>/PVFM/Al<sub>2</sub>O<sub>3</sub> based GPE matched with LiFePO<sub>4</sub> shows excellent electrochemical performance.展开更多
In the process of bulk photopolymerization of styrene initiated by AIBN decomposition polyvinyl benzophenone (PVB) can supply an effective cage for triplet-triplet energy transfer between PVB macromolecules and small ...In the process of bulk photopolymerization of styrene initiated by AIBN decomposition polyvinyl benzophenone (PVB) can supply an effective cage for triplet-triplet energy transfer between PVB macromolecules and small molecules of AIBN to influence the molecular weight of polystyrene in weak magnetic field (less than 0.035T), that was different from the case of polyvinyl naphthalene (PVN) which supplied cages for this system only in the stronger magnetic field (more than 0.2 T) studies. It was found that in the same conditions, PVN could exert more tremendous influences on the bulk photopolymerizatiou system of styrene than PVB because in the stronger magnetic field the triplet PVN had much longer life time than PVB.展开更多
Polyvinyl alcohol (PVA) stabilized Polyvinyl acetate (PVAc) dispersions-based wood adhesive has poor water and heat resistance. Recently, the addition of fillers in the wood adhesive is one of the most effective ways ...Polyvinyl alcohol (PVA) stabilized Polyvinyl acetate (PVAc) dispersions-based wood adhesive has poor water and heat resistance. Recently, the addition of fillers in the wood adhesive is one of the most effective ways to enhance the performance of PVAc wood adhesive. Inorganic fillers have unique characteristics to improve the performance of adhesive, such as small size, high surface energy and surface hardness. Hence, the present work investigates the applicability of calcium carbonate and clay incorporated 3% in situ emulsion polymerization PVAc wood adhesive. Effect on physical, thermal and mechanical properties was studied by viscosity, pH, contact angle measurement, differential scanning calorimetry (DSC) and pencil hardness test of films. Emulsions with 3% calcium carbonate and 3% clay were prepared and the shear strength of the applied adhesive on wood was measured. The viscosity of the adhesives was reduced in the case of the addition of calcium carbonate and increased in the case of clay. The mechanical properties like tensile strength of adhesives with calcium carbonate and clay were measured by a universal tensile machine (UTM). Thermal stability was studied by differential scanning calorimetry (DSC). The tensile shear strength demonstrates that clay can improve bonding strength as compared to calcium carbonate of PVAc adhesive in wet conditions. The hardness of PVAc films was also changed positively by the addition of calcium carbonate and clay. Thermal stability of PVAc was significantly improved as calcium carbonate and clay were added to PVAc. Here, we did a comparative study of the effect of the addition of calcium carbonate and clay filler materials in situ polymerization of PVAc on their different properties.展开更多
The microbial immobilization method using polyvinyl alcohol （PVA） gel as an immobilizing material was improved and used for entrapment of activated sludge. The oxygen uptake rate （OUR） was used to characterize the...The microbial immobilization method using polyvinyl alcohol （PVA） gel as an immobilizing material was improved and used for entrapment of activated sludge. The oxygen uptake rate （OUR） was used to characterize the biological activity of immobilized activated sludge. Three kinds of PVA-immobilized particles of activated sludge, that is, PVA-boric acid beads, PVA-sodium nitrate beads and PVA-orthophosphate beads were prepared, and their biological activity was compared by measuring the OUR value. The bioactivity of both autotrophic and heterotrophic microorganisms of activated sludge was determined using different synthetic wastewater media （containing 250 mg/L COD and 25 mg/L NH4^＋ -N）. The experimental results showed that the bioactivity and stability of the three kinds of immobilized activated sludge was greatly improved after activation. With respect of the bioactivity and the mechanical stability, the PVA-orthophosphate method may be a promising and economical technique for microbial immobilization.展开更多
Polyvinyl alcohol is a refractory compound widely used in industry. Here we report supercritical water oxidation of polyvinyl alcohol solution and desizing wastewater with and without sodium hydroxide addition. Howeve...Polyvinyl alcohol is a refractory compound widely used in industry. Here we report supercritical water oxidation of polyvinyl alcohol solution and desizing wastewater with and without sodium hydroxide addition. However, it is difficult to implement complete degradation of organics even though polyvinyl alcohol can readily crack under supercritical water treatment. Sodium hydroxide had a significant catalytic effect during the supercritical water oxidation of polyvinyl alcohol. It appears that the OH ion participated in the C-C bond cleavage of polyvinyl alcohol molecules, the CO2-capture reaction and the neutralization of intermediate organic acids, promoting the overall reactions moving in the forward direction. Acetaldehyde was a typical intermediate product during reaction. For supercritical water oxidation of desizing wastewater, a high destruction rate （98.25%） based on total organic carbon was achieved. In addition, cases where initial wastewater was alkaline were favorable for supercritical water oxidation treatment, but salt precipitation and blockage issues arising during the process need to be taken into account seriously.展开更多
Starch/polyvinyl alcohol （PVA） blended materials for using as a solid carbon source （SCS） were prepared by blending PVA and gelatinized starch in an aqueous solution system, in which PVA served as framework materi...Starch/polyvinyl alcohol （PVA） blended materials for using as a solid carbon source （SCS） were prepared by blending PVA and gelatinized starch in an aqueous solution system, in which PVA served as framework material and starch as carbon source. The optimization of starch content and temperature effects were investigated. It was indicated that higher denitrification efficiency could be achieved with more starch in the materials. The average specific denitrification rates were 0.93, 0.66, 0.37 and 0.36 mg/（g·day） corresponding to starch content of 70%, 60%, 40% and 30% respectively at 37℃. The denitrification rates increased when operating temperature was raised from 23℃ to 30℃ and then 37℃. The mechanism of carbon release was analyzed incorporating the experimental results of abiotic release in deionized water. The organic carbon was mainly hydrolyzed by microbes, and the biological release efficiencies were at the range of 89.2% to 96.0%. A long-term experiment with a continuous flow reactor with SCS material containing 70% starch was conducted to gain some experience for practical application. When the influent nitrate concentration was in the range of 35.2 to 39.1 mg/L, hydraulic retention time of 4 hr, and operating temperature of 30℃, a nitrogen removal efficiency up to 94.6% and denitrification rate of 0.217 kg/（m3.day） was achieved. The starch-based materials developed in this study can be used as a solid carbon source for tertiary nitrogen removal from secondary effluent.展开更多
Gasification of polyvinyl alcohol （PVA）-contaminated wastewater in supercritical water （SCW） was investigated in a continuous flow reactor at 723-873 K, 20-36 MPa and residence time of 20-450 s. The gas and liquid...Gasification of polyvinyl alcohol （PVA）-contaminated wastewater in supercritical water （SCW） was investigated in a continuous flow reactor at 723-873 K, 20-36 MPa and residence time of 20-450 s. The gas and liquid products were analyzed by GC/TCD, and TOC analyzer. The main gas products were H2, CH4, CO and CO2. Pressure change had no significant influence on gasification efficiency. Higher temperature and longer residence time enhanced gasification efficiency, and lower temperature favored the production of H2. The effects of KOH catalyst on gas product composition were studied, and gasification efficiency were analyzed. The TOC removal efficiency （RTOC）, carbon gasification ratio （RCG） and hydrogen gasification ratio （RHG） were up to 96.00%, 95.92% and 126.40% at 873 K and 60 s, respectively, which suggests PVA can be completely gasified in SCW. The results indicate supercritical water gasification for hydrogen generation is a promising process for the treatment ofPVA wastewater.展开更多
基金Ministry of Higher Education Malaysia(MoHE)and Universiti Putra Malaysia under the Fundamental Research Grant Scheme(FRGS)(Grant Nos.FRGS/1/2023/TK09/UPM/01/3 and 5540599。
文摘This review highlights the performance enhancement of polyvinyl alcohol(PVA)composites through the incorporation of nanofillers,focusing on mechanical,thermal,electrical and piezoelectric improvements.It examines bio-based fillers such as nanocellulose cellulose nanofibrils(CNF)and cellulose nanocrystals(CNC),and carbon-based fillers like graphene nanoplatelets(GNP)and carbon nanotubes(CNT).CNF and CNC increase tensile strength by up to 40%and 17.9%,respectively,due to their ability to reinforce polymer networks.CNC also improves thermal stability,raising degradation temperatures to approximately 327℃through enhanced hydrogen bonding.Electrical and piezoelectric properties are significantly improved,with dielectric behaviour enhanced by up to 107%and open-circuit voltage reaching 25.6 V,suitable for energy harvesting.GNP and CNT contribute by forming conductive networks within the PVA matrix,enabling superior electrical conductivity and consistent piezoresistive responses under strain.These characteristics make such composites ideal for applications in flexible electronics,sensors,structural health monitoring and other advanced fields.This synthesis of experimental results and critical insights underscores the broad utility and future potential of nanofillerenhanced PVA composites across aerospace,automotive,healthcare,and defence sectors.
基金supported by the research projects AP23486880 from the Ministry of Higher EducationScience of the Republic of Kazakhstan and 111024CRP2010,20122022FD4135 from Nazarbayev University.
文摘Recycling plastic waste into triboelectric nanogenerators(TENGs)presents a sustainable approach to energy harvesting,self-powered sensing,and environmental remediation.This study investigates the recycling of polyvinyl chloride(PVC)pipe waste polymers into nanofibers(NFs)optimized for TENG applications.We focused on optimizing the morphology of recycled PVC polymer to NFs and enhancing their piezoelectric properties by incorporating ZnO nanoparticles(NPs).The optimized PVC/0.5 wt%ZnO NFs were tested with Nylon-6 NFs,and copper(Cu)electrodes.The Nylon-6 NFs exhibited a power density of 726.3μWcm^(-2)—1.13 times higher than Cu and maintained 90%stability after 172800 cycles,successfully powering various colored LEDs.Additionally,a 3D-designed device was developed to harvest energy from biomechanical movements such as finger tapping,hand tapping,and foot pressing,making it suitable for wearable energy harvesting,automatic switches,and invisible sensors in surveillance systems.This study demonstrates that recycling polymers for TENG devices can effectively address energy,sensor,and environmental challenges.
基金Project supported by the National Natural Science Foundation of China (22301012)the R&D Program of Beijing Municipal Education Commission (KM202310011005)。
文摘Cerium oxide(CeO_(2)) has attracted much attention in recent years owing to its reversible switch ability in Ce^(3+)/Ce^(4+)redox to produce improved antioxidation properties for biomedical applications.Here,we report to embed the CeO_(2)nanospheres into the organic polymer network using electrostatic spinning technology to prepare polyvinyl alcohol(PVA)-encapsulated CeO_(2)nanospheres composite nanofibrous membranes(PVA-CeO_(2)) for the first time,which is beneficial to improving the dispersion and biocompatibility of CeO_(2)nanosphere without altering the original antioxidant properties of CeO_(2).Detailed characterization of the as-prepared composite nanofibrous membranes reveals that CeO_(2)was successfully introduced into the PVA fibers with strong interactions,thus enhancing the thermal stability and fracture toughness of the nanoifbers.As a result,PVA-CeO_(2)exhibits superior UV shielding performance,antioxidant performance and bacteriostatic performance.Meaningfully,PVA-CeO_(2)has strong absorbance in both UVA and UVB bands when the CeO_(2)concentration in the nanoifber membrane reaches 1.5 wt%,and shows an excellent scavenging effect on the 2,2-diphenyl-1-picrylhydrazyl(DPPH)radicals with a scavenging rate of 86.52%.Moreover,the Kirby-Bauer(K-B) method of agar diffusion test further confirms that PVA-CeO_(2)has antimicrobial ability against three types of representative strains,including Gram-positive bacteria(Staphylococcus aureus),Gram-negative bacteria(Escherichia coli) and fungi(Candida albicans).Importantly,no obvious cytotoxicity is observed for PVA-CeO_(2)even though the amount of embedded CeO_(2)nanosphere reaches as high as 1.5 wt%.This study reveals new avenues for improving the future smart design of CeO_(2)-based nanoifber membrane composite materials for biological antioxidants.
基金supported by the National Natural Science Foundation of China(Nos.52174239 and 52374259)the Program of China Scholarship Council(No.202406080114)Natural Sciences and Engineering Research Council of Canada(No.NSERC RGPIN 2024-04570).
文摘Chalcopyrite is often intergrown with talc,which,after grinding,forms ultrafine particles(<10μm)that readily coat chalcopyrite surfaces,hindering flotation and causing significant losses in tailings.This study evaluates polyvinyl acetate(PVAc),a thermoplastic polymer,as a selective flocculant to enhance reverse flot ation separation of chalcopyrite from ultrafine talc.Flotation tests showed that at a PVAc dosage of 40 mg/L,talc can be effectively and selectively removed,enabling efficient separation.Laser particle size analysis and scanning electron microscopy-energy dispersive spectrometry(SEM-EDS)confirmed that PVAc promotes selective talc aggregation without affecting chalcopyrite.X-ray photoelectron spectroscopy(XPS)and density functional theory(DFT)calculations revealed that hydrogen bonding between PVAc ester groups and surface hydroxyls on talc drives the flocculation,while chalcopyrite lacks suitable binding sites.PVAc adsorption also enhances talc hydrophobicity.Furthermore,particle-bubble coverage angle measurements and extended Derjaguin-Landau-Verwey-Overbeek(DLVO)theory theoretical calculations demonstrated that PVAc-induced flocculation increases attractive interactions between talc and bubbles,shifting the total interaction energy from repulsive to attractive and promoting bubble-particle attachment.This study clarifies the selective adsorption and flocculation mechanisms of PVAc and reveals the coupling of flocculation and flotation of ultrafine talc from a particle-bubble capture perspective,while expanding the potential of ester-based polymers for ultrafine mineral recovery.
基金the Beijing Natural Science Foundation(Z240029)the National Natural Science Foundation of China(22472004)+2 种基金China National Petroleum Corporation-Peking University Strategic Cooperation Project of Fundamental Researchthe New Cornerstone Science Foundationsupport from the Tencent Foundation through the Xplorer Prize.
文摘Polyvinyl chloride(PVC)is one of the most widely used plastic materials worldwide,particularly in long-life applications such as construction materials.However,recycling options for PVC waste remain limited,as conventional methods often degrade material quality or generate environmentally hazardous byproducts.In this study,we demonstrate an efficient process to convert PVC into new polymers with variable aromatic groups,using triethylsilane as the reductant in different solvents.This approach enables the production of polymers analogous to functionalized polyethylene(PE),which are typically challenging to obtain through conventional copolymerization or direct post-modification of C-H bonds in PE.The resulting polymers exhibit tunable thermal and mechanical properties depending on the introduced aromatic groups,which not only enhance the sustainable valorization of PVC waste,but also provide an opportunity for the synthesis of new functionalized polymers.
基金supported by the National Key Research and Development Program of China(No.2017YFB0309401)State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials of Soochow University。
文摘In this study,we proposed a novel and efficient way to strengthen polyvinyl alcohol(PVA)fiber using graphene quantum dots(GQDs).PVA molecular chains were grafted onto the surface of GQDs through Friedel-Crafts alkylation reaction to obtain functionalized GQDs(f-GQDs),and PVA/f-GQDs composite fiber was successfully prepared by wet spinning and post-treatment.The tensile strength and Young's modulus of the composite fiber reached up to 1229.24 MPa and 35.36 GPa which were approximately twice and 4 times those of the pure PVA fiber,respectively.Moreover,the composite fiber was demonstrated excellent resistance to solvents.In addition,the PVA/f-GQDs composite fiber showed intense and uniform cyan fluorescence,meanwhile,it could maintain stable solid-state fluorescence in acid and alkali solutions and particularly after long-term immersion in water(1 month).This study proposes a promising route for obtaining high-performance conventional fibers with some new functions.
文摘The purpose of this research work is to determine the removal efficiency of Cu^(2+)and Pb^(2+)ions using polyvinyl alcohol/neem leaf extract/chitosan(PVA/NLE/CS)composite films as adsorbent materials from an aqueous medium,with respect to pH,contact time,and adsorbent dosage.The synthesized composite material was characterized using Fourier Transform Infrared(FTIR)spectroscopy,thermogravimetric analysis-Derivative Thermogravimetry(TGA-DTG),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),and scanning electron microscopy-Energy Dispersive X-ray Spectroscopy(SEM-EDX).The antibacterial activity and swelling response of the material were studied using suitable methodologies.The FTIR study confirmed the interactions among PVA,chitosan,and neem leaf extract.The TGA data reveal the excellent thermal stability of the developed composite films.The SEM micrograph indicates a homogeneous phase morphology with good compatibility among chitosan,the monomer,and the leaf extract.The antibacterial study revealed that the prepared PVA/NLE/CS films exhibit improved antibacterial activity against bacterial growth.It was found that at pH 6.0,the adsorption capacity for both toxic metal ions is maximum,and decreases with a further rise in pH.At this pH,the adsorption capacity of PVA/NLE/CS films increases with a gradual increase in adsorbent dosage,and at a specific pH,the adsorption capacity for Cu^(2+)is greater than that for Pb^(2+).The adsorption efficiency is a function of contact time and was found to be maximal at 180 min.Hence,the developed composite material is effective for the removal of metal ions from wastewater.
基金National Drug Sampling Inspection Project(No.NMPA Drug Admin[2024]1).
文摘The current quality standard for polyvinyl alcohol eye drops lacks an impurity assessment,despite the potential impact of raw material impurities on product safety.To strengthen quality control and ensure drug safety,an investigation into the impurity profile of the formulation was conducted,and an HPLC-UV method was developed for impurity quantification.The method validation was performed using an H-type cation exchange column.A total of 116 batches of polyvinyl alcohol eye drops from four manufacturers and two batches of the innovator drug were analyzed.Formic acid was detected exclusively in 0.4 mL samples from Company A and the innovator drug,with concentrations below 0.002%in both cases.Acetic acid was identified in samples from all manufacturers,with levels not exceeding 0.1%.The method demonstrated high specificity and sensitivity,making it well-suited for the quantification of formic and acetic acids in polyvinyl alcohol eye drops.The presence of formic acid was attributed to excipients,whereas acetic acid originated from raw materials and was further generated during pH adjustment in manufacturing.Although the overall impurity levels were low and posed minimal risk to drug safety,manufacturers should remain vigilant regarding impurity control to maintain product quality.
文摘Polyvinyl alcohol (PVA) is a water-soluble polymer material, which has excellent mechanical properties, high strength, good stretchability and certain antibacterial ability, and is widely used in the fields of architecture, medical treatment, textile and so on. This paper briefly introduces the preparation methods of polyvinyl alcohol, mainly focusing on the application research progress of polyvinyl alcohol. By summarizing the application of polyvinyl alcohol fiber, polyvinyl alcohol film and polyvinyl alcohol adhesive in various industries, the development of polyvinyl alcohol industry is further prospected.
基金Supported by National Natural Science Foundation(20773109)Fund for Social Development in Zhenjiang(SH2006067)~~
文摘[Objective] The aim of this study was to discuss the optimizing preparation conditions of polyvinyl alcohol(PVA)hollow microsphere and its application in the production of slow-release urea fertilizer.[Method]PVA hollow microsphere was prepared by the emulsion chemical cross-linking method,while its composition,morphology and particle size was analyzed by technologies of FT-IR,SEM and TEM respectively.Thus,factors such as rate of emulsified speed,crosslink temperature and linking agent amount with effects on morphology and particle size of hollow microsphere were also discussed in this study.Furthermore,based on the optimizing preparation conditions,PVA fertilizer carrier microsphere was prepared by coating urea to investigate its sustained release effect on urea.[Result]The optimizing preparation conditions of polyvinyl alcohol(PVA)hollow microsphere were as follows:rate of emulsified speed 6 000 r/min,crosslink temperature 35 ℃ and linking agent amount 25 ml.PVA fertilizer carrier microsphere had significant sustained release effect on urea,and the optimal cross-linking time was 3 hours.[Conclusion]This study provides theoretical basis for the development of new slow-release fertilizer.
文摘A novel technology of preparation of felt-metal supported modified polyvinyl alcohol（PVA） ultrafiltration（UF） membrane was invented, which could avoid the blockage of the holes of support layer and the leakage of the casting solution through the holes of support layer. Felt-metal supported ferric sulfate modified PVA composite UF membranes were prepared by the innovative technology. The results show that the composite membranes are used to treat 1 000 mg/L oil/water emulsion at trans-membrane pressure from 0.25 to 0.45 MPa, the permeate flux is from 36 to 52 L/（m2·h）, and the retention of chemical oxygen demand（COD） is over 92%. The composite membrane resistance increases with the increase of trans-naembrane pressure.
文摘Synthetic wood adhesives, consisting of urea-formaldehyde resins (UF), phenol-formaldehyde resins (PF), melamine-formaldehyde resins (MF), and polyurethane resins, are widely used. For UF and MF, most investigations are concerned with reducing free formaldehyde content;for PF, most studies focused on finding new alternative chemicals to replace phenol. These adhesives come under the Carcinogenic, Mutagenic, and Reprotoxic chemicals (CMR) category. Due to global energy issues and dependency on petroleum sources, the focus has shifted to look for alternative and renewable raw material sources for wood adhesives. Conventionally available wood adhesives are polyvinyl alcohol (PVA) stabilized, with drawbacks like poor water resistance, poor heat resistance, low-temperature workability, and it’s based on petroleum resources. Polyvinyl acetate (PVAc) is non-resistant to moisture polymer, and if such adhesive joints are exploited in a moist environment, its strength substantially decreases. Sufficiently moisture-resistant adhesive joints are obtained by modifying PVAc dispersion with special compounds like reactive comonomer, Silanes, and modified PVA. To improve the workability at low temperature, Vinyl acetate (VAc) is copolymerized with specific comonomers like butyl acetate without affecting the performance properties. Here, we aim to present an overview of the research trend of PVAc-based adhesives in the wood industry. The review summarizes the current state of research PVAc-based adhesives.
基金supported by Hitachi Plant Technologies,Ltd.and Hitachi Ltd.(China),State key laboratory of hydraulics and mountain river engineering in Sichuan University
文摘Polyvinylidene fluoride （PVDF） hollow fiber membranes prepared from spinning solutions with different polyvinyl pyrrolidone （PVP） contents （1% and 5%） at different extrusion rates were obtained by wet/dry phase process keeping all other spinning parameters constant. In spinning these PVDF hollow fibers, dimethylacetamide （DMAc） and PVP were used as a solvent and an additive, respectively. Water was used as the inner coagulant. Dimethylformamide （DMF） and water （30/70） were used as the external coagulant. The performances of membranes were characterized in terms of water flux, solute rejection for the wet membranes. The structure and morphology of PVDF hollow fiber were examined by BET adsorption, dry/wet weight method and scanning electron microscopy （SEM）. It is found that the increase in PVP content and extrusion rate of spinning solution can result in the increase of water flux and decrease of solute rejection. The improvements of interconnected porous structure and pore size are induced by shear-thinning behavior of spinning solution at high extrusion rates, which could result in the increase of water flux of hollow fiber membranes. The increase of extrusion rate also leads to the increase of membrane thickness due to the recovery effect of elastic property of polymer chains.
文摘Al<sub>2</sub>O<sub>3</sub>/PVFM/Al<sub>2</sub>O<sub>3</sub> trilayer membranes are prepared by means of simple coating of PVA-Al<sub>2</sub>O<sub>3</sub> solution onto both sides of PVFM thin membranes, which is prepared via phase inversion method. The characteristics of the trilayer membranes and gel polymer electrolytes are investigated using FESEM, tensile testing apparatus, thermal shrinkage test, EIS and charge-discharge test. When inorganic Al<sub>2</sub>O<sub>3</sub> particles are used to coat the PVFM membrane, drawbacks associated with gel-type membranes, namely, poor mechanical strength and thermal stability are greatly improved. Lithium ion cell with the Al<sub>2</sub>O<sub>3</sub>/PVFM/Al<sub>2</sub>O<sub>3</sub> based GPE matched with LiFePO<sub>4</sub> shows excellent electrochemical performance.
文摘In the process of bulk photopolymerization of styrene initiated by AIBN decomposition polyvinyl benzophenone (PVB) can supply an effective cage for triplet-triplet energy transfer between PVB macromolecules and small molecules of AIBN to influence the molecular weight of polystyrene in weak magnetic field (less than 0.035T), that was different from the case of polyvinyl naphthalene (PVN) which supplied cages for this system only in the stronger magnetic field (more than 0.2 T) studies. It was found that in the same conditions, PVN could exert more tremendous influences on the bulk photopolymerizatiou system of styrene than PVB because in the stronger magnetic field the triplet PVN had much longer life time than PVB.
文摘Polyvinyl alcohol (PVA) stabilized Polyvinyl acetate (PVAc) dispersions-based wood adhesive has poor water and heat resistance. Recently, the addition of fillers in the wood adhesive is one of the most effective ways to enhance the performance of PVAc wood adhesive. Inorganic fillers have unique characteristics to improve the performance of adhesive, such as small size, high surface energy and surface hardness. Hence, the present work investigates the applicability of calcium carbonate and clay incorporated 3% in situ emulsion polymerization PVAc wood adhesive. Effect on physical, thermal and mechanical properties was studied by viscosity, pH, contact angle measurement, differential scanning calorimetry (DSC) and pencil hardness test of films. Emulsions with 3% calcium carbonate and 3% clay were prepared and the shear strength of the applied adhesive on wood was measured. The viscosity of the adhesives was reduced in the case of the addition of calcium carbonate and increased in the case of clay. The mechanical properties like tensile strength of adhesives with calcium carbonate and clay were measured by a universal tensile machine (UTM). Thermal stability was studied by differential scanning calorimetry (DSC). The tensile shear strength demonstrates that clay can improve bonding strength as compared to calcium carbonate of PVAc adhesive in wet conditions. The hardness of PVAc films was also changed positively by the addition of calcium carbonate and clay. Thermal stability of PVAc was significantly improved as calcium carbonate and clay were added to PVAc. Here, we did a comparative study of the effect of the addition of calcium carbonate and clay filler materials in situ polymerization of PVAc on their different properties.
基金Project supported by the National Natural Science Foundation of China(No.50327802,50325824,50678089).
文摘The microbial immobilization method using polyvinyl alcohol （PVA） gel as an immobilizing material was improved and used for entrapment of activated sludge. The oxygen uptake rate （OUR） was used to characterize the biological activity of immobilized activated sludge. Three kinds of PVA-immobilized particles of activated sludge, that is, PVA-boric acid beads, PVA-sodium nitrate beads and PVA-orthophosphate beads were prepared, and their biological activity was compared by measuring the OUR value. The bioactivity of both autotrophic and heterotrophic microorganisms of activated sludge was determined using different synthetic wastewater media （containing 250 mg/L COD and 25 mg/L NH4^＋ -N）. The experimental results showed that the bioactivity and stability of the three kinds of immobilized activated sludge was greatly improved after activation. With respect of the bioactivity and the mechanical stability, the PVA-orthophosphate method may be a promising and economical technique for microbial immobilization.
基金supported by the National High Technology Research and Development Program of China (No.2006AA06Z313)the Program for New Century Excellent Talents in University of Chinese Education Ministry (No.NCET-07-0678)the Opened Fund of Jiangsu Key Lab for Clean Energy and Power Machinery Engineering (No.QK08003)
文摘Polyvinyl alcohol is a refractory compound widely used in industry. Here we report supercritical water oxidation of polyvinyl alcohol solution and desizing wastewater with and without sodium hydroxide addition. However, it is difficult to implement complete degradation of organics even though polyvinyl alcohol can readily crack under supercritical water treatment. Sodium hydroxide had a significant catalytic effect during the supercritical water oxidation of polyvinyl alcohol. It appears that the OH ion participated in the C-C bond cleavage of polyvinyl alcohol molecules, the CO2-capture reaction and the neutralization of intermediate organic acids, promoting the overall reactions moving in the forward direction. Acetaldehyde was a typical intermediate product during reaction. For supercritical water oxidation of desizing wastewater, a high destruction rate （98.25%） based on total organic carbon was achieved. In addition, cases where initial wastewater was alkaline were favorable for supercritical water oxidation treatment, but salt precipitation and blockage issues arising during the process need to be taken into account seriously.
基金supported by the Ministry of Science and Technology of China (No.2009AA063805)
文摘Starch/polyvinyl alcohol （PVA） blended materials for using as a solid carbon source （SCS） were prepared by blending PVA and gelatinized starch in an aqueous solution system, in which PVA served as framework material and starch as carbon source. The optimization of starch content and temperature effects were investigated. It was indicated that higher denitrification efficiency could be achieved with more starch in the materials. The average specific denitrification rates were 0.93, 0.66, 0.37 and 0.36 mg/（g·day） corresponding to starch content of 70%, 60%, 40% and 30% respectively at 37℃. The denitrification rates increased when operating temperature was raised from 23℃ to 30℃ and then 37℃. The mechanism of carbon release was analyzed incorporating the experimental results of abiotic release in deionized water. The organic carbon was mainly hydrolyzed by microbes, and the biological release efficiencies were at the range of 89.2% to 96.0%. A long-term experiment with a continuous flow reactor with SCS material containing 70% starch was conducted to gain some experience for practical application. When the influent nitrate concentration was in the range of 35.2 to 39.1 mg/L, hydraulic retention time of 4 hr, and operating temperature of 30℃, a nitrogen removal efficiency up to 94.6% and denitrification rate of 0.217 kg/（m3.day） was achieved. The starch-based materials developed in this study can be used as a solid carbon source for tertiary nitrogen removal from secondary effluent.
基金Project supported by the National Natural Science Foundation of China(No.20277010)the Hi-Tech Research and Development Program(863) of China(No.2006AA062378).
文摘Gasification of polyvinyl alcohol （PVA）-contaminated wastewater in supercritical water （SCW） was investigated in a continuous flow reactor at 723-873 K, 20-36 MPa and residence time of 20-450 s. The gas and liquid products were analyzed by GC/TCD, and TOC analyzer. The main gas products were H2, CH4, CO and CO2. Pressure change had no significant influence on gasification efficiency. Higher temperature and longer residence time enhanced gasification efficiency, and lower temperature favored the production of H2. The effects of KOH catalyst on gas product composition were studied, and gasification efficiency were analyzed. The TOC removal efficiency （RTOC）, carbon gasification ratio （RCG） and hydrogen gasification ratio （RHG） were up to 96.00%, 95.92% and 126.40% at 873 K and 60 s, respectively, which suggests PVA can be completely gasified in SCW. The results indicate supercritical water gasification for hydrogen generation is a promising process for the treatment ofPVA wastewater.
