Artykuły w czasopismach: „(poly)vinyl Alcohol(PVA) Nanocomposite”

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PANDA, BHABANI SHANKAR, i MOHAMMED ANSAR AHEMAD. "Synthesis of Silver Nanoparticles from Mimusops elengi Extract of Raw Fruits and Characterization of PVA-Silver Polymer Nanocomposite Films". Asian Journal of Chemistry 33, nr 4 (20.03.2021): 762–66. http://dx.doi.org/10.14233/ajchem.2021.23074.

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The present work concerns on the synthesis of silver nanoparticles at 25 ºC using raw fruits extract of Bakul (Mimusops elengi) tree via chemical reduction route development of poly(vinyl alcohol) PVA-silver polymer nanocomposite films. The nanocomposite films were subjected to characterization by UV-visible, FTIR, X-ray diffraction, field emission scanning electron microscope (FESEM) and thermal studies. The UV-visible spectrum shows a characteristic broad absorption band observed near 465 nm suggesting presence of silver nanoparticles in polymer nanocomposites (PNCs) film. The vibrational band shift of –OH group of poly(vinyl alcohol) in the presence of nanoparticle designated the chemical interaction between –OH group of poly(vinyl alcohol) and silver nanoparticles. The FESEM study confirmed that PVA is not only acted as a capping agent, but also a cross-linking agent. X-ray diffraction study shows that the existence of AgNPs in the poly nanocomposite film and nanoaparticles are crystalline in nature. Thermal studies suggest that the enhanced thermal stability is because of the good packing of the polar crystallites in β-PVA composites as compared to the non-polar α-phase of neat poly(vinyl alcohol) (PVA).

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Bandyopadhyay, Abhijit, Mousumi De Sarkar i Anil K. Bhowmick. "Solution Rheology of Poly(vinyl alcohol)/Silica Hybrid Nanocomposites". Polymers and Polymer Composites 13, nr 5 (lipiec 2005): 429–42. http://dx.doi.org/10.1177/096739110501300501.

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The solution behavior of polymer/silica hybrid nanocomposites was investigated using a Brookfield viscometer. The nanocomposites were prepared using the sol-gel technique with tetraethoxysilane (TEOS) as the precursor for silica. The sol-gel reaction was carried out in the pH range of 1.0-2.0, which was maintained by the addition of concentrated HCl. Poly (vinyl alcohol) (PVA)/silica nanocomposites demonstrated a bigger rise in solution viscosity after continuous measurement for five days than either- acrylic rubber (ACM)/silica or epoxidised natural rubber (ENR)/silica nanocomposites. Detailed investigation of the PVA/silica system indicated that it exhibited Newtonian behaviour when the solutions contained (5 or 7.5 wt% of PVA,) even when increasing the TEOS concentration to 50 wt%, although at one particular TEOS concentration (10 wt%), the nanocomposite was pseudoplastic when the concentration of PVA was increased to 10 wt%. The reinforcement factor [Formula: see text] for those PVA/silica hybrid nanocomposites containing 5 wt% of PVA deviated strongly from the Guth-Smallwood prediction. Instead they obeyed a relationship of the type ηmax = η0(1 + aϕb), where a = 4.45 and b = 0.38, calculated for this system. The viscosity decreased with increasing temperature for both PVA and the representative nanocomposite with 30 wt% TEOS (PVA30), although the activation energy for flow of the nanocomposite did not vary to a great extent.

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Wang, Mengqing, Yanling Xu, Haihu Tan, Lijian Xu, Changfan Zhang i Jianxiong Xu. "Multicolor Luminescent Anti-Counterfeiting Barcode Based on Transparent Lanthanide-Doped NaYF4/Poly(Vinyl Alcohol) Nanocomposite with Tunable Full-Color Upconversion Emission". Nanoscience and Nanotechnology Letters 10, nr 3 (1.03.2018): 365–72. http://dx.doi.org/10.1166/nnl.2018.2631.

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In this paper, we report the synthesis of transparent lanthanide-doped NaYF4 phosphors/poly(vinyl alcohol) (UCPs/PVA) nanocomposites with full-color upconversion emission for construction of multicolor luminescent anti-counterfeiting barcode. By deliberate design of water-dispersible lanthanidedoped NaYF4 upconversion phosphors and precise control of the doped lanthanide ions (dopant pairs and molar ratio), three-primary RGB UCPs with fine red, green and blue upconversion emission were synthesized. The as-prepared three-primary RGB UCPs were incorporated into poly(vinyl alcohol) (PVA) matrix at a fixed concentration to balance the transparence and fluorescence intensity of the UCPs/PVA nanocomposite. The combination of emissions from different types of UCPs with selected ratios in PVA matrix was used to prepare UCPs/PVA nanocomposite with various upconversion emissions. It was demonstrated that the separation distance between UCPs was large enough to suppress inter-particle energy transfer, and thus the emissions of each UCPs were well preserved. This facilitated the fabrication of UCPs/PVA nanocomposite with tunable full-color upconversion emission based on the trichromatic additive color theory. The relevance of these multicolor UCPs/PVA nanocomposites to barcode materials and application in anti-counterfeiting field were also confirmed.

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Patil, Mallikarjunagouda, Shridhar N. Mathad, Arun Y. Patil, Muhammad Nadeem Arshad, Hajar Saeed Alorfi, Madhu Puttegowda, Abdullah M. Asiri, Anish Khan i Naved Azum. "Synthesis and Characterization of Microwave-Assisted Copolymer Membranes of Poly(vinyl alcohol)-g-starch-methacrylate and Their Evaluation for Gas Transport Properties". Polymers 14, nr 2 (17.01.2022): 350. http://dx.doi.org/10.3390/polym14020350.

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Poly(vinyl alcohol) (PVA) is an excellent membrane-forming polymer and can be modified with potato starch and methyl acrylate monomers to obtain copolymers with improved physical and chemical properties. The study presents the synthesis of poly(vinyl alcohol)-g-starch-poly(methyl acrylate) PVA-g-St-g-PMA copolymers using microwave irradiation technique and potassium persulfate initiator. Solution casting and solvent evaporation methods were adopted for the fabrication of polyvinyl alcohol-g-starch-acrylamide composite membranes. The synthesized graft copolymer was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and thermal analysis. The modified nanocomposite membranes were showed very promising results with the parameters permeability and selectivity. The nanocomposite membranes exhibited the advantages of easy handling and reuse.

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Lee, Min Eui, i Hyoung-Joon Jin. "Nanocomposite Films of Poly(vinyl alcohol)-Grafted Graphene Oxide/Poly(vinyl alcohol) for Gas Barrier Film Applications". Journal of Nanoscience and Nanotechnology 15, nr 10 (1.10.2015): 8348–52. http://dx.doi.org/10.1166/jnn.2015.11257.

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Poly(vinyl alcohol) (PVA) composites containing graphene oxide (GO) functionalized with PVA were synthesized via the esterification of the carboxylic groups of GO. The presence of PVA-grafted GO (PVA-g-GO) in the PVA matrix induced strong interactions between the chains of the PVA matrix and allowed the PVA-g-GO to be uniformly dispersed throughout the matrix. The grafting of PVA to GO increased the gas barrier properties of the GO/PVA composites because of the increased compatibility between GO and PVA. The PVA-g-GO/PVA composites were used to coat the surface of poly(ethylene terephthalate) films. These coated films exhibited excellent gas barrier properties; the film containing 0.3 wt% of PVA-g-GO had an oxygen transmission rate (OTR) of 0.025 cc/(m2 · day) and an optical transmittance of 83.8%. As a result, PVA-g-GO/PVA composites that exhibited enhanced gas barrier properties were prepared with a solution mixing method.

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Diken, Mehmet Emin, Berna Koçer Kizilduman, Begümhan Yilmaz Kardaş, Enes Emre Doğan, Mehmet Doğan, Yasemin Turhan i Serap Doğan. "Synthesis, characterization, and their some chemical and biological properties of PVA/PAA/nPS hydrogel nanocomposites: Hydrogel and wound dressing". Journal of Bioactive and Compatible Polymers 35, nr 3 (maj 2020): 203–15. http://dx.doi.org/10.1177/0883911520921474.

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The nanocomposite hydrogels were prepared by dispersing of the nanopomegranate seed particles into poly(vinyl alcohol)/poly(acrylic acid) blend matrix in an aqueous medium by the solvent casting method. These hydrogels were characterized using scanning electron microscopy, Fourier transform infrared spectra, differential scanning calorimetry, and optical contact angle instruments. The nanopomegranate seed, blend, and hydrogel nanocomposites were tested for microbial activity. In addition, cytocompatibilities of these blend and hydrogel nanocomposites/composites were tested on human lymphocyte with in vitro MTS cell viability assays. Fourier transform infrared spectra revealed that esterification reaction took place among functional groups in the structure of poly(vinyl alcohol) and poly(acrylic acid). The hydrophilic properties of all hydrogels decreased with increasing nanopomegranate seed content. The mean diameters of the nanopomegranate seed particles were about 88 nm. Nanopomegranate seed particles demonstrated antibacterial properties against gram-positive bacteria, Staphylococcus aureus, and gram-negative bacteria, Escherichia coli. The lymphocyte viabilities increased after addition of nanopomegranate seeds into the polymer blend. The swelling behavior of blend and hydrogels was dependent on the cross-linking density created by the reaction between poly(vinyl alcohol)/poly(acrylic acid) blend and nanopomegranate seed. Scanning electron microscopy images were highly consistent with Fourier transform infrared spectra, differential scanning calorimetry, and antibacterial activity results.

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Asa'di, Sima, Masoud Frounchi i Susan Dadbin. "Nanomagnetic Poly(vinyl alcohol) Hydrogels". Advanced Materials Research 829 (listopad 2013): 539–43. http://dx.doi.org/10.4028/www.scientific.net/amr.829.539.

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Surface modified magnetic nanoparticles (M-NPs) were synthetized and stabilized in poly (vinyl-alcohol) solution. The solutions with various magnetic nanoparticles contents were gamma-irradiated and magnetic poly (vinyl-alcohol) (M-PVA) hydrogels were synthesized. The magnetic hydrogels and also the un-irradiated magnetic poly (vinyl alcohol) nanocomposite films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), Fourier transform infrared spectroscopy (FTIR) and mechanical measurement. The M-NPs were uniformly dispersed in the polymer matrix due to a strong interaction between the surface-modified M-NPs and polymer matrix. Physical properties of the M-PVA hydrogels, including gel fraction and equilibrium water content were measured to evaluate the applicability of these hydrogels for biomedical applications. XRD, FTIR and VSM results indicated that there are important changes in crystalline, chemical and magnetic properties of hydrogels, arising from irradiation.

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Fujino, Shigeru, i Hiroshi Ikeda. "Room Temperature Imprint Using Crack-Free Monolithic SiO2-PVA Nanocomposite for Fabricating Microhole Array on Silica Glass". Journal of Nanomaterials 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/584320.

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This paper aims to fabricate microhole arrays onto a silica glass via a room temperature imprint and subsequent sintering by using a monolithic SiO2-poly(vinyl alcohol) (PVA) nanocomposite as the silica glass precursor. The SiO2-PVA suspension was prepared from fumed silica particles and PVA, followed by drying to obtain tailored SiO2-PVA nanocomposites. The dependence of particle size of the fumed silica particles on pore size of the nanocomposite was examined. Nanocomposites prepared from 7 nm silica particles possessed suitable mesopores, whereas the corresponding nanocomposites prepared from 30 nm silica particles hardly possessed mesopores. The pore size of the nanocomposites increased as a function of decreasing pH of the SiO2-PVA suspension. As a consequence, the crack-free monolithic SiO2-PVA nanocomposite was obtained using 7 nm silica particles via the suspension at pH 3. Micropatterns were imprinted on the monolithic SiO2-PVA nanocomposite at room temperature. The imprinted nanocomposite was sintered to a transparent silica glass at 1200°C in air. The fabricated sintered glass possessed the microhole array on their surface with aspect ratios identical to the mold.

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Bai, Lu, Yuan Gao, Shuai Li i Li Ping Zhang. "Preparation and Characterization of Pol(vinyl Alcohol）/ Cellulose Nanocomposites". Advanced Materials Research 233-235 (maj 2011): 2383–86. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.2383.

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In this study, nanocomposite membranes were prepared from poly (vinyl alcohol) (PVA) with different amounts of cellulose nanocrystals as filler and characterized by thermogravimetry (TG). Swelling sorption behavior of various feed alcohol mixtures was investigated at 80°C, and found that NCC in PVA matrix could help to reduce the overall membrane swelling. Mechanical properties of the nanocomposite membranes were examined in relation to NCC content in the composite. Optimal NCC content in the composite was found to be 3 wt% in terms of its overall properties as compared to neat PVA film. With the addition of 3 wt% NCC to PVOH the ultimate tensile strength showed improvement compared to pure PVA. The PVA/ NCC nanocomposite membrane had shown increases in elongation at low filler loadings. The TG analysis demonstrated that the nanocomposite membranes exhibited higher thermal resistance.

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Saleh, Hoda H., Rehab Sokary i Zakaria I. Ali. "Radiation – induced preparation of polyaniline/poly vinyl alcohol nanocomposites and their properties". Radiochimica Acta 107, nr 8 (26.07.2019): 725–35. http://dx.doi.org/10.1515/ract-2018-3003.

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Abstract Polyaniline (PANI) nanoparticles and PANI/poly vinyl alcohol (PVA) nanocomposite films were synthesized by the oxidative polymerization of aniline and ammonium peroxodisulfate (APS), as an oxidizing agent in aqueous medium. The PANI/PVA nanocomposite films were exposed to γ-irradiation after oxidative polymerization. Synthesized polyaniline (PANI) nanoparticles and PANI/PVA nanocomposite films were characterized by attenuated total reflectance infrared spectroscopy (FTIR-ATR), X-ray diffraction, high resolution scanning electron microscopy, (HRSEM) high resolution transmission electron microscopy, (HRTEM) and UV-VIS absorption spectroscopy. Energy band gap of PANI nanofibers was determined from Tauc’s plots which equal 4.2 eV. Scanning electron microscopy images show that chemically synthesized of polyaniline has nanofibers structure and irradiated PANI/PVA nanocomposite have a mixture of nanorod and nanosphere structures. The transmission electron microscopy show that chemically synthesized of polyaniline has average length in the range 34 ± 10 nm with less wide distribution, where as the irradiated PANI/PVA nanocomposite has coreshell structure.

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Cobos, Mónica, Iker De-La-Pinta, Guillermo Quindós, María Jesús Fernández i María Dolores Fernández. "Synthesis, Physical, Mechanical and Antibacterial Properties of Nanocomposites Based on Poly(vinyl alcohol)/Graphene Oxide–Silver Nanoparticles". Polymers 12, nr 3 (24.03.2020): 723. http://dx.doi.org/10.3390/polym12030723.

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The design of new materials with antimicrobial properties has emerged in response to the need for preventing and controlling the growth of pathogenic microorganisms without the use of antibiotics. In this study, partially reduced graphene oxide decorated with silver nanoparticles (GO–AgNPs) was incorporated as a reinforcing filler with antibacterial properties to poly(vinyl alcohol) (PVA) for preparation of poly(vinyl alcohol)/graphene oxide-silver nanoparticles nanocomposites (PVA/GO–AgNPs). AgNPs, spherical in shape and with an average size of 3.1 nm, were uniformly anchored on the partially reduced GO surface. PVA/GO–AgNPs nanocomposites showed exfoliated structures with improved thermal stability, tensile properties and water resistance compared to neat PVA. The glass transition and crystallization temperatures of the polymer matrix increased with the incorporation of the hybrid. The nanocomposites displayed antibacterial activity against Staphylococcus aureus and Escherichia coli in a filler content- and time-dependent manner. S. aureus showed higher susceptibility to PVA/GO–AgNPs films than E. coli. Inhibitory activity was higher when bacterial cells were in contact with nanocomposite films than when in contact with leachates coming out of the films. GO–AgNPs based PVA nanocomposites could find application as wound dressings for wound healing and infection prevention.

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Kausar, A. "Innovations in Poly(Vinyl Alcohol) Derived Nanomaterials". Advances in Materials Science 20, nr 3 (1.09.2020): 5–22. http://dx.doi.org/10.2478/adms-2020-0013.

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AbstractPoly(vinyl alcohol) (PVA) has been considered as an important commercial synthetic thermoplastic polymer. PVA is a low cost, reasonably processable, optically transmitting, heat stable, and mechanically robust plastic. PVA-based nanomaterials usually comprise of the nanocomposites (PVA/graphene, PVA/carbon nanotube, PVA/nanodiamond, PVA/metal nanoparticle) and nanofibers. The structural, optical, mechanical, and electrical properties of the PVA-based nanomaterials have been enhanced with nanofiller addition or nanostructuring. This review offers fundamentals and advanced aspects of poly(vinyl alcohol) and the derived nanomaterials. It highlights recent advances in PVA nanocomposites and nanofibers for potential applications. The PVA-based nanomaterials have been successfully employed in fuel cells, sensors, batteries, membranes, electronics, and drug delivery relevances. The challenges and opportunities to strengthen the research fields of PVA-based nanomaterials have also been presented.

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He, Shaojian, Jiaqi Wang, Mengxia Yu, Yang Xue, Jianbin Hu i Jun Lin. "Structure and Mechanical Performance of Poly(vinyl Alcohol) Nanocomposite by Incorporating Graphitic Carbon Nitride Nanosheets". Polymers 11, nr 4 (3.04.2019): 610. http://dx.doi.org/10.3390/polym11040610.

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Owing to the high aspect ratio, the two-dimensional (2D) inorganic nanofillers have attracted extensive interest in the field of polymer reinforcement. In this work, graphitic carbon nitride (g-C3N4) nanosheets were obtained via thermal condensation of melamine and were then ultrasonically exfoliated in water, which was confirmed by atomic force microscopy (AFM) and TEM. Poly(vinyl alcohol) (PVA)/g-C3N4 nanocomposites were achieved by solution casting using water as the solvent. The structure and mechanical performance of PVA/g-C3N4 nanocomposites were studied. It was found that the g-C3N4 nanosheets were well dispersed in the PVA matrix. The introduction of g-C3N4 nanosheets increased the glass transition temperature and crystallinity of the nanocomposites, leading to the improved mechanical performance. Compared with the pure PVA, the PVA/g-C3N4 nanocomposite with 0.50 wt% g-C3N4 nanosheets showed ~70.7% enhancement in tensile strength, up from 51.2 MPa to 87.4 MPa.

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Yang, Seong Baek, Sung Min Park, Dong Jun Kwon, Jae-Cheon Shin, Yeasmin Sabina i Jeong Hyun Yeum. "Novel Poly(vinyl alcohol)/Clay Nanocomposite Film Prepared by the Heterogeneous Saponification of Poly(vinyl acetate)/Clay Nanocomposite Film". Science of Advanced Materials 12, nr 3 (1.03.2020): 319–25. http://dx.doi.org/10.1166/sam.2020.3643.

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A novel PVA/clay (MMT) film is prepared for the first time based on the saponification of the PVAc/MMT film in the presence of heterogeneous conditions. With the help of optical microscopy, the characteristics and surface morphology of the saponified PVA/MMT film is confirmed. It is found to contain black MMT nanoparticles in PVAc films as the content of MMT increased. According to atomic force microscopy results, PVAc/MMT films shows unexpected surface roughness owing to the slow progress of the saponification reaction in the presence of MMT contents in the PVAc matrix. The thermal stability of the PVA/MMT film is measured using thermal gravimetric analyses. The results indicate that thermal stability increases significantly when the MMT concentration increases. The entire structure of the PVA/MMT nanocomposite has been elucidated using XRD. To prove the differences between the PVAc/MMT and the PVA/MMT films, XRD measurements and Fourier transform Infrared spectroscopy analyses are utilized.

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Rahim, A., K. Liaqat, S. Fazil, Z. Liaqat, S. A. H. Shah, W. Rehman, M. Farooq, S. Haq i M. Nawaz. "Synthesis and characterization of covalently grafted graphene oxide – poly (vinyl alcohol)/ carbon nanotubes nanocomposites". Digest Journal of Nanomaterials and Biostructures 16, nr 3 (lipiec 2021): 1147–55. http://dx.doi.org/10.15251/djnb.2021.163.1147.

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Herein we have reported a simple procedure for the synthesis of covalently grafted graphene oxide poly (vinyl alcohol) (PVA-g-GO). Later on, multiwalled carbon nanotubes (MWCNTs) were dispersed in this PVA-g-GO matrix by sequential stirring and sonication. Nanocomposites with varying weight percent of graphene oxide (GO) and multiwalled carbon nanotubes (MWCNTs) were synthesized. These nanocomposites have shown excellent thermal and mechanical stability. It also appears that presence of graphene oxide has assisted in dispersing the MWCNTs. Combine effect of GO and MWCNTs has resulted in the nanocomposite with electrical conductivity of 2.02E-09 S/cm.

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GANDHI, S., M. R. GOPINATHAN NAIR i R. ANBARASAN. "SONOCHEMICAL SYNTHESIS AND CHARACTERIZATION OF NANOSTRUCTURED Mn3O4 AND ITS SURFACE CATALYTIC EFFECT ON POLY (VINYL ALCOHOL)". International Journal of Nanoscience 11, nr 01 (luty 2012): 1250004. http://dx.doi.org/10.1142/s0219581x12500044.

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Nanosized manganese oxide was synthesized with help of ultrasound and its polymer nanocomposite with poly (vinyl alcohol) was prepared. The incorporated nanosized manganese oxide is involved in the surface catalytic effect on PVA matrix. Nanosized manganese oxide and its polymer composite were characterized by FTIR, XRD, DSC, TGA, SEM and HRTEM methods. This PVA- Mn3O4 nanocomposite system has improved thermally resistant than pristine PVA.

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Liu, Fu Juan, Qiu Na Cui, Ji Huan He i Dong Dong Fei. "Preparation, Characterization and Ionizing Radiation Protection Properties of Electrospun Nanofibrous Mats Embedded with Erbium Oxide (Er₂O₃) Nanoparticles". Journal of Nano Research 27 (marzec 2014): 121–27. http://dx.doi.org/10.4028/www.scientific.net/jnanor.27.121.

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Ionizing radiation directly causes serious damage to human health, and a protective system capable of absorbing or reflecting ionizing radiation is required urgently. In this work, electrospun poly (vinyl alcohol) (PVA) and Poly (vinyl Alcohol)/Erbium Oxide (PVA/Er2O3) nanocomposite fibrous mats were fabricated. These PVA or PVA/Er2O3 composite nanofibers were completely characterized using scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, Thermogravimetric Analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Furthemore, air permeability and ionizing radiation protection properties of these mats were also measured. Under a certain constant electropinning condition, the PVA or PVA/Er2O3 composite nanofibers showed an excellent morphology. The ionizing radiation protection capability of nanofibrous mats is considerably improved when incorporated with Er2O3 nanoparticles.

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Pisesweerayos, Prasit, Somsak Dangtip, Pitt Supaphol i Toemsak Srikhirin. "Conductive Nanocomposite Aligned Fibers of PVA-AgNPs-PEDOT/PSS". Advanced Materials Research 1033-1034 (październik 2014): 1009–19. http://dx.doi.org/10.4028/www.scientific.net/amr.1033-1034.1009.

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Poly (vinyl alcohol)-silver nanoparticles (PVA:AgNPs), and poly (vinyl alcohol)-silver nanoparticles-poly (3, 4-ethylene dioxythiophene)/poly (styrene sulfonate) (PVA:AgNPs: PEDOT/ PSS) were generated as ultra-fine electrospun fibers using the aligned fiber mat and aligned single fiber techniques. SEM and TEM were used to confirm the morphology, diameter size, and fiber alignment of the ultra-fine fibers. A two-probe technique was utilized to assess the electrical conductivity of the ultrafine fibers. The highest conductivity of PVA:AgNPs, (10 %w/v:0.75 %w/v) with a fiber diameter of 0.152 μm, with voltage applied at 17.5 kV within a 20 min collection period in the electrospinning process, was 43.20 S/cm; whereas the highest conductivity of PVA:AgNPs: PEDOT/PSS, (10 %w/v:0.25 %w/v:0.084 %w/v), with a fiber diameter of 0.158 μm and voltage applied at 17.5 kV within a 45 min collection period in the electrospinning process, was 92.18 S/cm.

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Peng, Zheng, Ling Xue Kong i Si Dong Li. "Study on Thermooxidative Degradation of Poly(Vinyl Alcohol)/Silica Nanocomposite Prepared with SAM Technique". Journal of Metastable and Nanocrystalline Materials 23 (styczeń 2005): 375–78. http://dx.doi.org/10.4028/www.scientific.net/jmnm.23.375.

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The thermooxidative degradation of poly (vinyl alcohol)/silica (PVA/SiO2) nanocomposite prepared with self-assembly monolayer (SAM) technique is investigated by using a thermogravimetry (TG) and Fourier transform infrared spectroscopy coupled thermogravimetry (FTIR/TG). The results show that although the thermooxidative degradation process of prepared nanocomposite is similar to that of the pure PVA, its thermooxidative stability has been greatly improved.

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Yilmaz Dogan, Hazal, Yasin Altin i Ayşe Çelik Bedeloğlu. "Fabrication and properties of graphene oxide and reduced graphene oxide reinforced Poly(Vinyl alcohol) nanocomposite films for packaging applications". Polymers and Polymer Composites 30 (styczeń 2022): 096739112211133. http://dx.doi.org/10.1177/09673911221113328.

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Petroleum-based polymers have a wide range of uses in the packaging industry, including films, food packaging, rigid containers, foamed containers, medical products, etc. This study focuses on improving the properties of polyvinyl alcohol (PVA) based material systems, one of the most popular water-soluble biopolymers, to reduce the waste of petroleum-based plastics, which are widely used. Polyvinyl alcohol (PVA) nanocomposite films containing low concentrations (0.05–1%) of graphene oxide (GO) and reduced graphene oxide (rGO) were produced via the solution casting method. When electrical properties of nanocomposite films were evaluated, the addition of 1 wt% GO and rGO resulted in a 36% and 45% decrease in the volumetric resistance of the films as well as a decrease in surface resistance of 24.5% and 34.9%, respectively. The maximum tensile strength of 1% GO and rGO-reinforced PVA nanocomposites was found to be ∼59 MPa and ∼68 MPa with an increase of 20% and 38% compared to neat PVA films, respectively. The average Young’s modulus of 1% GO and rGO-reinforced PVA nanocomposites also increased from 2561 MPa to 3515 MPa and 4219 MPa with an increase of 37% and 65%, respectively. As a result, the electrical conductivity, Young’s modulus, maximum tensile strength, thermal properties, and optical absorption of nanocomposite films increased by adding GO and rGO to PVA. The results show that the produced nanocomposite film may be a promising material for packaging applications.

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Cho, Beom-Gon, Shalik Ram Joshi, Seongjin Lee, Shin-Kwan Kim, Young-Bin Park i Gun-Ho Kim. "Enhanced Mechanical and Antibacterial Properties of Nanocomposites Based on Poly(vinyl Alcohol) and Biopolymer-Derived Reduced Graphene Oxide". Polymers 13, nr 4 (18.02.2021): 615. http://dx.doi.org/10.3390/polym13040615.

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Functionalized graphene–polymer nanocomposites have gained significant attention for their enhanced mechanical, thermal, and antibacterial properties, but the requirement of multi-step processes or hazardous reducing agents to functionalize graphene limits their current applications. Here, we present a single-step synthesis of thermally reduced graphene oxide (TrGO) based on shellac, which is a low-cost biopolymer that can be employed to produce poly(vinyl alcohol) (PVA)/TrGO nanocomposites (PVA–TrGO). The concentration of TrGO varied from 0.1 to 2.0 wt.%, and the critical concentration of homogeneous TrGO dispersion was observed to be 1.5 wt.%, below which strong interfacial molecular interactions between the TrGO and the PVA matrix resulted in improved thermal and mechanical properties. At 1.5 wt.% filler loading, the tensile strength and modulus of the PVA–TrGO nanocomposite were increased by 98.7% and 97.4%, respectively, while the storage modulus was increased by 69%. Furthermore, the nanocomposite was 96% more effective in preventing bacterial colonization relative to the neat PVA matrix. The present findings indicate that TrGO can be considered a promising material for potential applications in biomedical devices.

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Bai, Lu, Ping Qu, Shuai Li, Yuan Gao i Li Ping Zhang. "Poly(vinyl Alcohol)/Cellulose Nanocomposite Pervaporation Membranes for Ethanol Dehydration". Materials Science Forum 675-677 (luty 2011): 383–86. http://dx.doi.org/10.4028/www.scientific.net/msf.675-677.383.

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In this study, pervaporation membranes were prepared from poly( vinyl alcohol) (PVA) with different amounts of cellulose nanocrystals as filler, and characterized by scanning electron microscopy (SEM). The characterization results demonstrated that cellulose nanocrystal particles dispersed homogeneously within the PVA matrix. Moreover, the pervaporation performance of these membranes was investigated using the separation of ethanol-water mixture as model system. Among all the prepared membranes, PVA/cellulose nanocomposite membrane containing 1 wt% cellulose nanocrystals exhibited the best pervaporation performance, whose averaged permeation flux reduced slightly but separation factor was increased from 83 to 163 for 80% aqueous solution of ethanol at 80 °C respectively.

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Mallakpour, Shadpour, i Forough Motirasoul. "Capturing Cd2+ ions from wastewater using PVA/α-MnO2–oleic acid nanocomposites". New Journal of Chemistry 42, nr 6 (2018): 4297–307. http://dx.doi.org/10.1039/c8nj00304a.

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AlFannakh, Huda, S. S. Arafat i S. S. Ibrahim. "Synthesis, electrical properties, and kinetic thermal analysis of polyaniline/ polyvinyl alcohol - magnetite nanocomposites film". Science and Engineering of Composite Materials 26, nr 1 (28.01.2019): 347–59. http://dx.doi.org/10.1515/secm-2019-0020.

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AbstractPolyaniline-poly vinyl alcohol (PANI-PVA) conducting blends containing 15 wt% aniline were synthesized by in situ polymerization of aniline. Three-phase polymer blended nanocomposites with different contents of magnetite (5, 10 and 15 wt.%) were also synthesized. We measured the current-voltage (I-V) curves for the conducting blend and its magnetite nanocomposite. We also measured their thermal stability, and performed kinetic analysis through thermogravimetric analysis. We observed that the three phase nanocomposites showed enhanced electrical conductivity compared with that of the conductive blend, and no electrical hysteresis. The PVA/PANi blend was more stable above 350∘C and the addition of Fe3O4 enhanced the thermal stability of the conductive blend. The apparent activation energy of the three phase nanocomposites was greater than those of both the pure PVA and PVA/PANi samples. These results suggest that such three phase nanocomposites could be used in a range of applications.

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Stylios, George K., i Tao Yu Wan. "Investigating SMART Membranes and Coatings by In Situ Synthesis of Iron Oxide Nanoparticles in PVA Hydrogels". Advances in Science and Technology 60 (wrzesień 2008): 32–37. http://dx.doi.org/10.4028/www.scientific.net/ast.60.32.

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This paper reports a novel method of developing SMART nanocomposite membranes and coatings by in situ synthesis of iron oxide particles in a Poly(vinyl alcohol) (PVA)matrix, using co-precipitation of different amounts of Fe(II) and Fe(III) taken in an alkaline medium. Poly(vinyl alcohol) was used to encapsulate iron oxide nanoparticles, as scaffold for particle nucleation and its influence on particle size and on magnetic properties were studied. The ferrogels were prepared by a freeze/thawing process of the solutions containing magnetite nanoparticles. Magnetite particles with an average diameter of 20-40 nm were obtained homogeneously within the matrix because of the tridimensional structure and chelating capacities of PVA. Calcium-alginate PVA gel was used to encapsulate the iron oxide/PVA nanocomposite. The mechanical properties and the saturation magnetization of the system were measured. The combination of magnetic properties of iron nanoparticles with the biocompatibility of calcium-alginate suggests that these materials have great potential for use as controlled delivery systems activated externally by magnetic stimuli.

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Kumar, S. Vasantha, V. A. Sajeevkumar, Johnsy George i Sunny Kumar. "Enhancing properties of polyvinyl alcohol film using sorghum starch nanocrystals – A cost effective filler from natural source". Defence Life Science Journal 2, nr 2 (31.05.2017): 169. http://dx.doi.org/10.14429/dlsj.2.11380.

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<p>Poly Vinyl Alcohol (PVA) nanocomposite films with Sorghum Starch Nanocrystals (SSN) were prepared by incorporating various concentrations of SSN in PVA. SSN was isolated using acid hydrolysis of sorghum starch. The morphological studies of SSN using Atomic Force Microscopy (AFM) revealed that the particle size varied from 65 to 68 nm. The mechanical properties of PVA-SSN nanocomposite films indicated an improvement in tensile strength and percentage elongation at break when compared to that of PVA films. This can be attributed to the stronger interaction of PVA with SSN due to hydrogen bonding. Besides this, PVA-SSN nanocomposite films also exhibited good thermal properties. Thus, the use of SSN (a cost effective filler from natural source) imparted superior properties to the PVA nanocomposite films, which will be beneficial for applications such as food packaging. </p>

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Handoko, Fauzi, i Yusril Yusuf. "Synthesis and Physicochemical Properties of Poly(vinyl) Alcohol Nanocomposites Reinforced with Nanocrystalline Cellulose from Tea (Camellia sinensis) Waste". Materials 14, nr 23 (24.11.2021): 7154. http://dx.doi.org/10.3390/ma14237154.

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The purpose of this study was to utilize cellulose from tea waste as nanocrystalline cellulose (NCC), which is used as a filler in poly(vinyl) alcohol (PVA) nanocomposites. To obtain the NCC, a chemical process was conducted in the form of alkali treatment, followed by bleaching and hydrolysis. Nanocomposites were formed by mixing PVA with various NCC suspensions. With chemical treatment, lignin and hemicellulose can be removed from the tea waste to obtain NCC. This can be seen in the functional groups of cellulose and the increase in crystallinity. The NCC had a mean diameter of 6.99 ± 0.50 nm. Furthermore, the addition of NCC to the PVA nanocomposite influenced the properties of the nanocomposites. This can be seen in the general increase in opacity value, thermal and mechanical properties, and crystallinity, as well as the decrease in the value of the swelling ratio after adding NCC. This study has revealed that NCC from tea waste can be used to improve the physicochemical properties of PVA film.

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Nasar, Gulfam, Hazrat Amin, Fawad Ahmad i Shahbaz Nazir. "Structural and Thermal Behavior Evaluation of Ag-PVA Nanocomposites Synthesized via Chemical Reduction Technique". Journal of Materials and Physical Sciences 1, nr 1 (30.06.2020): 19–25. http://dx.doi.org/10.52131/jmps.2020.0101.0003.

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Silver nanoparticles were prepared via process of chemical reduction using sodium borohydride as reductant. The prepared nanoparticles were then utilized for synthesizing various compositions of nanocomposites with polymeric matrix of poly (vinyl alcohol). For doing so, the nanoparticles were dispersed in the polymer solution by vigorous stirring. The solutions of the nanocomposites were cast in films. The nanocomposite films were used for various characterization techniques; out of which three are being reported in this communication; XRD, TGA/DTA and SEM. The upshot of XRD proposes a semi-crystalline nature of synthesized nanocomposite. The crystalline character of the nanocomposite enhances with an increasing doping concentration of the prepared nanoparticles. Thermal analysis suggests the degradation pattern of the polymer nanocomposite material and represents that thermal stability improves as the silver nanoparticles are added. The SEM micrograph reveals a uniform surface with a well dispersed nanoparticle in the polymer matrix.

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Amaregouda, Yamanappagouda, Tilak Gasti i Kantharaju Kamanna. "Optoelectronic, microstructural, ecofriendly and photo-catalytic evaluation of Aspartic acid cross-linked Poly (vinyl alcohol)/Copper Oxidenanotubescomposite films". IOP Conference Series: Materials Science and Engineering 1221, nr 1 (1.03.2022): 012008. http://dx.doi.org/10.1088/1757-899x/1221/1/012008.

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Abstract The present work describes design and preparation of aspartic acid (Asp) cross-linked Poly (vinyl alcohol) (PVA)/Copper oxide nanotubes (CuO NTs) composite filmsvia solution casting method.The CuO NTswere prepared by novel biogenic method using RobiniaPseudoacaciaLeaf Extract.Theprepared CuO NTs and PVA/CuO/Asp nanocomposite filmsarecharacterized by various techniques.The adsorption and photo-catalytic efficiencies of PVA/CuO/Asp nanocomposite films were compared with pristine CuO NTs. The adsorption capacity of PVA/CuO/Asp nanocomposite films showed higher due to presence of active sites, high surface activity and semiconducting nature of CuO NTs and Asp embedded in PVA matrix. The comparative photocatalytic activities of the CuO NTsand PVA/CuO NTs/Asp nanocomposite filmsare examinedagainst methylene blue (MB) as a substrate degradation, and film PVA/CuO NTs/Asp showed highest (up to 77%) degradation compared to other films. The improved photocatalytic behavior of PVA nanocomposite film attributed to its narrower band gapreduces the recombination rate of exited electron-hole, enhanced UV-Vis absorption intensity, extinction coefficient and refractive index, improved utilization of sunlight and enhanced adsorption of dye due to functional groups, biodegradable, surface wettability, hydrophilic surface and self-cleaning nature.

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Lee, Eunsil, Youjung Song i Seungsin Lee. "Crosslinking of lignin/poly(vinyl alcohol) nanocomposite fiber webs and their antimicrobial and ultraviolet-protective properties". Textile Research Journal 89, nr 1 (25.10.2017): 3–12. http://dx.doi.org/10.1177/0040517517736468.

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Lignin/poly(vinyl alcohol) (PVA) nanocomposite fibers with different lignin concentrations were developed via electrospinning to investigate further possible applications of lignin, an under-utilized renewable biomass material. The antimicrobial and ultraviolet (UV) absorption properties of lignin/PVA nanocomposite fibers were evaluated to determine whether the inherent functionalities of lignin remain in the final material. An environmentally benign crosslinking method was sought to increase the stability of lignin/PVA nanocomposite fibers in aqueous media. The crosslinking and insolubilization of the lignin/PVA nanocomposite fibers was achieved by combining several crosslinking techniques: water vapor treatment at 80℃ for 180 min, photo-irradiation for 30 min under visible light at a distance of 17 cm, and heat treatment at 200℃ for 60 min. Both lignin/PVA nanocomposite fiber webs—containing 50 and 85 wt% of lignin at a 3.0 g/m2 web area density, respectively—showed a 99.9% reduction rate against Staphylococcus aureus, but no reduction against Escherichia coli. The same systems exhibited ultraviolet protection factors (UPF) of >50, indicating excellent UV protection. These findings demonstrate the potential of lignin-based composite fibers, and may widen the range of applications for this biomass material.

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Luo, Qiaomei, Yangyang Shan, Xia Zuo i Jiaqi Liu. "Anisotropic tough poly(vinyl alcohol)/graphene oxide nanocomposite hydrogels for potential biomedical applications". RSC Advances 8, nr 24 (2018): 13284–91. http://dx.doi.org/10.1039/c8ra00340h.

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Cao, Yuan-Cheng, Wenjun Wei, Jiyan Liu, Qingliang You, Feiyan Liu, Qian Lan, Chang Zhang, Chang Liu i Jinxing Zhao. "The Preparation of Graphene Reinforced Poly(vinyl alcohol) Antibacterial Nanocomposite Thin Film". International Journal of Polymer Science 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/407043.

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Methylated melamine grafted polyvinyl benzylchloride (mm-g-PvBCl) was prepared which was used as additive in poly(vinyl alcohol) (PVA) and graphene nanosheets (GNs) were used to reinforce the mechanical strength. Using casting method, antimicrobial nanocomposite films were prepared with the polymeric biocide loading lever of 1 wt%, 5 wt%, and 10 wt%. Thermogravimetric analysis (TGA) characterization revealed the 2.0 wt% of graphene content in resultant nanocomposites films. XRD showed that the resultant GNs 2 theta was changed from 16.6 degree to 23.3 degree. Using Japanese Industry Standard test methods, the antimicrobial efficiency for the loading lever of 1 wt%, 5 wt%, and 10 wt% was 92.0%, 95.8%, and 97.1%, respectively, against gram negative bacteriaE. coliand 92.3%, 99.6%, and 99.7%, respectively, against the gram positiveS. aureus. These results indicate the prepared nanocomposite films are the promising materials for the food and drink package applications.

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Riyadh, Sayed M., Khaled D. Khalil i Ali H. Bashal. "Structural Properties and Catalytic Activity of Binary Poly (vinyl alcohol)/Al2O3 Nanocomposite Film for Synthesis of Thiazoles". Catalysts 10, nr 1 (10.01.2020): 100. http://dx.doi.org/10.3390/catal10010100.

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A solution casting technique was applied to prepare a binary poly (vinyl alcohol)/Al2O3 nanocomposite. The structural properties of nanocomposite were investigated using Fourier-transform infrared spectra, field emission scanning electron microscope, energy dispersive X-ray analyses, and X-ray diffraction. The hybrid PVA/Al2O3 film exhibited a conspicuous catalytic performance for synthesis of thiazole derivatives under mild reaction conditions. Moreover, the optimization of catalytic efficiency and reusability of this nanocomposite have been investigated.

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Cobos, Mónica, M. Fernández i M. Fernández. "Graphene Based Poly(Vinyl Alcohol) Nanocomposites Prepared by In Situ Green Reduction of Graphene Oxide by Ascorbic Acid: Influence of Graphene Content and Glycerol Plasticizer on Properties". Nanomaterials 8, nr 12 (6.12.2018): 1013. http://dx.doi.org/10.3390/nano8121013.

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The enhanced properties of polymer nanocomposites as compared with pure polymers are only achieved in the presence of well-dispersed nanofillers and strong interfacial adhesion. In this study, we report the preparation of nanocomposite films based on poly(vinyl alcohol) (PVA) filled with well dispersed graphene sheets (GS) by in situ reduction of graphene oxide (GO) dispersed in PVA solution using ascorbic acid (L-AA) as environmentally friendly reductant. The combined effect of GS content and glycerol as plasticizer on the structure, thermal, mechanical, water absorption, and water barrier properties of PVA/GS nanocomposite films is studied for the first time. Higher glass transition temperature, lower crystallinity, melting, and crystallization temperature, higher mechanical properties, and remarkable improvement in the thermal stability compared to neat PVA are obtained as a result of strong interfacial interactions between GS and PVA by hydrogen bonding. PVA/GS composite film prepared by ex situ process is more brittle than its in situ prepared counterpart. The presence of GS improves the water barrier and water resistance properties of nanocomposite films by decreasing water vapor permeability and water absorption of PVA. This work demonstrates that the tailoring of PVA/GS nanocomposite properties is enabled by controlling GS and glycerol content. The new developed materials, particularly those containing plasticizer, could be potential carriers for transdermal drug delivery.

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35

Ma, Jiaojiao, Ying Li, Xiande Yin, Yu Xu, Jia Yue, Jianjun Bao i Tao Zhou. "Poly(vinyl alcohol)/graphene oxide nanocomposites prepared by in situ polymerization with enhanced mechanical properties and water vapor barrier properties". RSC Advances 6, nr 55 (2016): 49448–58. http://dx.doi.org/10.1039/c6ra08760d.

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Wang, Yang, Zhu Wang, Piming Ma, Huiyu Bai, Weifu Dong, Yi Xie i Mingqing Chen. "Strong nanocomposite reinforcement effects in poly(vinyl alcohol) with melanin nanoparticles". RSC Advances 5, nr 89 (2015): 72691–98. http://dx.doi.org/10.1039/c5ra12333j.

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The high dispersibility of melanin NPs in the PVA was achieved by using a simple casting method. The mechanical properties remarkably increased at a low content of melanin, and was even superior to conventional carbon-based nanofillers.

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37

Yuan, Xiao Ya. "Effective Reinforcement of Graphene in Poly (vinyl alcohol) Nanocomposites at Low Loading via Enhanced Interfacial Interaction". Advanced Materials Research 391-392 (grudzień 2011): 250–54. http://dx.doi.org/10.4028/www.scientific.net/amr.391-392.250.

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The graphene/poly(vinyl alcohol) nancomposites with enhanced filler-matrix interfacial interaction were fabricated via water-blending partially reduced graphene oxide (PRGO) and poly(vinyl alcohol)(PVA). The nanocomposites were characterized by X-ray Diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), Scanning Electron Microscopy(SEM), thermogravimetry(TG). The results showed that the graphene nanosheets were homogeniously dispersed in the PVA matrix and enhanced interfacial adhesion was greatly enhanced due to new covalent linkage and hydrogen-bonding between graphene and PVA backbone. The mechanical and thermal properties of the nanocomposites were significantly improved at low graphene loadings. An 116% increase in tensile strength and a 19°C improvement of onset thermal degradation temperature were achieved by the addition of only 0.8 wt% graphene.

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38

Bekhit, Mohamad, Asmaa Sobhy, Zakaria I. Ali i Sameh M. Gafar. "Efficient monitoring of dosimetric behaviour for copper nanoparticles through studying its optical properties". Radiochimica Acta 107, nr 6 (26.06.2019): 523–29. http://dx.doi.org/10.1515/ract-2018-3010.

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Abstract A novel high-dose dosimeter based on γ radiation reduction of copper ions and formation of copper metal inside polymer matrix were investigated. γ radiation induced synthesis of copper nanoparticles (CuNPs) in poly vinyl alcohol films were studied by UV-Visible Spectrophotometer, X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). The optical absorption spectra showed that the Cu/PVA nanocomposite films have surface plasmon resonance (SPR) of copper nanoparticles which depending on irradiation doses. Upon γ irradiation these films turns its color from faint blue to deep reddish brown depending on metal ion concentration. The XRD pattern and FTIR spectrum confirm the formation of the CuNPs. The response of Cu/PVA nanocomposite dosimeters depends on both the irradiation doses and concentration of copper precursor. The dose range for these films was from 50 to 650 kGy, revealing its important applications for high dose dosimetry. Cu/PVA nanocomposites films exhibit good post-irradiation stability in dark and light.

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39

Hourd, A. C., R. T. Baker i A. Abdolvand. "Structural characterisation of printable noble metal/poly(vinyl-alcohol) nanocomposites for optical applications". Nanoscale 7, nr 32 (2015): 13537–46. http://dx.doi.org/10.1039/c5nr03636d.

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Mohammadi, H., D. Boughner, L. E. Millon i W. K. Wan. "Design and simulation of a poly(vinyl alcohol)—bacterial cellulose nanocomposite mechanical aortic heart valve prosthesis". Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 223, nr 6 (9.07.2009): 697–711. http://dx.doi.org/10.1243/09544119jeim493.

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In this study, a polymeric aortic heart valve made of poly(vinyl alcohol) (PVA)—bacterial cellulose (BC) nanocomposite is simulated and designed using a hyperelastic non-linear anisotropic material model. A novel nanocomposite biomaterial combination of 15 wt % PVA and 0.5 wt % BC is developed in this study. The mechanical properties of the synthesized PVA—BC are similar to those of the porcine heart valve in both the principal directions. To design the geometry of the leaflets an advance surfacing technique is employed. A Galerkin-based non-linear finite element method is applied to analyse the mechanical behaviour of the leaflet in the closing and opening phases under physiological conditions. The model used in this study can be implemented in mechanical models for any soft tissues such as articular cartilage, tendon, and ligament.

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Mohammed, Ali Jasim, i Sameer H. Al-nesrawy. "Nano Ferrite Incorporated Poly (Vinyl Pyrrolidone (PVP) /Poly (Vinyl Alcohol (PVA) Blend: Preparation and Investigation of Structural, Morphological and Optical Properties". NeuroQuantology 20, nr 4 (6.04.2022): 251–58. http://dx.doi.org/10.14704/nq.2022.20.3.nq22087.

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In this paper, the ferrite Cux Ni1-x FeO3 when (x=0.1) has been prepared by the co-precipitation method and examined through the XRD -diffraction and confirming the face center cubic spinel phase (FCC) which attributed to the ferrite and found that these materials was Nano-scale. Then with different content of ferrite nanoparticle (1, 3and 5 wt.%) additive to the (PVP/PVA) polymer matrix to synthesis (PVP/PVA/ferrite) nanocomposite by using casting method and study the Fourier transformation infrared (FTIR), (FE-SEM) and UV-Vis. Spectrophotometer. The FTIR confirming that there is no interactions between (PVP/PVA) polymer matrix and ferrite nanoparticles for all the sample prepared. From FESEM, the uniform morphology dispersed of ferrite inside the PVP/PVA blend with spherically shaped nanoparticles and the average grain size increased with increasing of concentration of ferrite. The absorption, absorption coefficient, transmittance and indirect energy band gap has been investigate.

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Lužajić Božinovski, Tijana, Danica Marković, Vera Todorović, Bogomir Prokić Bolka, Ivan Milošević, Neda Drndarević, Katarina Nešović, Rhee Kyong Yop i Vesna Mišković-Stanković. "In Vivo Investigation of Soft Tissue Response of Novel Silver/Poly(Vinyl Alcohol)/ Graphene and Silver/Poly(Vinyl Alcohol)/Chitosan/Graphene Hydrogels Aimed for Medical Applications – The First Experience". Acta Veterinaria 68, nr 3 (1.09.2018): 321–39. http://dx.doi.org/10.2478/acve-2018-0027.

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Abstract In this paper, we have shown for the fi rst time the soft tissue response of novel silver/ poly(vinyl alcohol)/graphene (Ag/PVA/Gr) and silver/poly(vinyl alcohol)/chitosan/ graphene (Ag/PVA/CHI/Gr) nanocomposite hydrogels aimed for medical applications. These novel hydrogels were produced by in situ electrochemical synthesis of silver nanoparticles in the polymer matrices as described in our previously published works. Both Ag/PVA/Gr and Ag/PVA/CHI/Gr, as well as controls Ag/PVA, Ag/PVA/CHI and commercial Suprasorb©hydrogel discs, were implanted in the subcutaneous tissue of rats. Implants with the surrounding tissue were dissected after post-implantation on days 7, 15, 30 and 60, and then processed for histological examination. The tissue irritation index (TIrI) score, according to ISO 10993-6, 2007, as well as the number of leukocytes in the peri-implant zone and connective tissue capsule thickness were examined. The results show that each TIrI score, the leukocyte number around the implanted materials and capsule thickness gradually decreased during the observation period. At the endpoint of follow-up, the Ag/PVA/CHI/Gr implant was surrounded with a thinner capsule, while both the TIrI score and the number of leukocytes of the peri-implant zone were greater compared to the Ag/PVA/Gr implant. Despite the observed differences, we can conclude that our in vivo experiment suggested that both novel hydrogels were biocompatible and suitable for medical use.

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Silvério, Hudson Alves, Wilson Pires Flauzino Neto i Daniel Pasquini. "Effect of Incorporating Cellulose Nanocrystals from Corncob on the Tensile, Thermal and Barrier Properties of Poly(Vinyl Alcohol) Nanocomposites". Journal of Nanomaterials 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/289641.

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The effect of incorporating cellulose nanocrystals from corncob (CNC) on the tensile, thermal, and barrier properties of poly(vinyl alcohol) (PVA) nanocomposites was evaluated. The CNC were prepared by sulfuric acid hydrolysis at 45°C for 60 minutes, using 15 mL of H2SO4(9.17 M) for each gram of fiber. The CNC60presented a needle-shaped morphology, high crystallinity (83.7%), good initial degradation temperature (236°C), average length (L) of210.8±44.2 nm, diameter (D) of4.15±1.08 nm, and high aspect ratio (L/D) of53.4±15.8. PVA/CNC nanocomposite films with different filler loading levels (3, 6, and 9% by wt) were prepared by casting. The ultimate tensile strength (UTS), thermal stability (TS), light transmittance (Tr) and water vapor permeability (Pw) of the nanocomposites were measured. When compared to neat PVA film, the UTS of the nanocomposites improved significantly, by 140.2%,Pwdecreased up to 28.73%, and there were no significant changes in TS. The nanocomposites also showed excellent Tr in the visible region, maintaining substantially equivalent transparency. These improvements in the nanocomposites' properties suggest a close association between filler and matrix, besides indicating that the CNC were well dispersed and adherent to the polymer matrix.

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Saeedi, Fariba, Arash Montazeri, Yaser Bahari, Malihe Pishvaee i Mohammad Ranjbar. "Synthesis and Characterization of Chitosan-Poly Vinyl Alcohol-Graphene Oxide Nanocomposites". International Journal of Chemoinformatics and Chemical Engineering 7, nr 1 (styczeń 2018): 1–12. http://dx.doi.org/10.4018/ijcce.2018010101.

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In this article, nanocomposites based on Chitosan (CS)/ poly vinyl alcohol (PVA) and graphene oxide (GO) nanoparticles were prepared by casting the stable aqueous mixture of the components in a mold. The prepared nanocomposites were characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffractions (XRD) and viscosity measurement. Scanning Electron Microscopy (SEM) results indicated that the GO was uniformly dispersed in the polymer matrix. The water uptake ability of nanocomposites increased with an increasing the PVA content. While, the addition of GO to CS/PVA lead to a decrease in the degree of water absorption. According to the rheological analysis the viscosity of the samples decreased with increasing the GO weight percent in CS/PVA mixture.

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Yan, Xiaofei, Jie Fang, Jianjun Gu, Chenkai Zhu i Dongming Qi. "Flame Retardancy, Thermal and Mechanical Properties of Novel Intumescent Flame Retardant/MXene/Poly(Vinyl Alcohol) Nanocomposites". Nanomaterials 12, nr 3 (29.01.2022): 477. http://dx.doi.org/10.3390/nano12030477.

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Poly(vinylphosphonic acid) (PVPA) and polyethylenepolyamine (PEPA) are used as novel intumescent flame retardants to improve the properties of MXene (2D Ti3C2Tx)/poly(vinyl alcohol) (PVA) nanocomposites. We investigated the flame-retardant properties, thermal stability, and mechanical properties of MXene/PVA nanocomposites. The results show that MXene was homogeneously dispersed in the PVA matrix containing PVPA and PEPA. PVPA and PEPA effectively improved the flame-retardant properties of MXene/PVA nanocomposites and they did not obviously change the thermal degradation of the MXene/PVA nanocomposites. Moreover, MXene improved the thermal stability of the PVA matrix. The elongation at break of MXene/PVA nanocomposites reached its maximum when the MXene mass fraction was 1.0 wt.%, regardless of whether PVPA and PEPA were present in the PVA matrix, whereas the tensile strength and Young’s modulus of MXene/PVA nanocomposites increased with the increase in MXene content in the PVA matrix.

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Kobayashi, Hisatoshi. "PVA-HAp Nanocomposites for Artificial Cornea". Advances in Science and Technology 53 (październik 2006): 9–16. http://dx.doi.org/10.4028/www.scientific.net/ast.53.9.

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To solve the shortage of the donor cornea in Japan, we are developing a poly(vinyl alcohol) hydrogel based keratoprosthesis. Minimum requirements for a keratoprosthesis include light transparency, non-toxicity, and nutrition and fluid permeability. Earlier clinical trials had frequently failed because corneal epithelial down growth occurred between the host cornea and the materials, and the materials were finally rejected from the host cornea. The major cause of this rejection is the weak adhesion between the host cornea and the prosthesis. In order to achieve the firm fixation of the artificial cornea to host cornea, composites of collagen-immobilized poly(vinyl alcohol) hydrogel with hydroxyapatite(PVA-HAp nano composites) were synthesized. The preparation method, characterization, and the results of corneal cell adhesion and proliferation on the composite materials were studied. The PVA-HAp nano composites were successfully synthesized. Chick embryonic keratocyto-like cells were well attached and proliferated on the PVA-HAp composites. This material showed potential for keratoprosthesis.

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Makharza, Sami, Maryam Faroun, Mohammad Bawwab i Ibrahim Afaneh. "GRAPHENE OXIDE REINFORCED POLY (VINYL ALCOHOL) NANOCOMPOSITE: FABRICATION AND CHARACTERIZATION FOR THERMAL AND MECHANICAL PROPERTIES INVESTIGATIONS". Engineering Structures and Technologies 11, nr 4 (31.12.2019): 125–29. http://dx.doi.org/10.3846/est.2019.12473.

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We reported the fabrication of poly (vinyl alcohol) incorporated with two different sizes of graphene oxide particles. Scanning electron microscopy (SEM) revealed two sizes of graphene oxide, the first size is as prepared GO_300 nm and the second size is 100nm after hard sonication. The alteration in thermal and mechanical properties of PVA/ GO (5, 10, 15, 20%) nanocomposite compering with PVA are mainly due to the uniform dispersion of GO particles in the polymer matrix and huge interfacial interaction between PVA and GO sheets. Differential scanning calorimetry shows obvious changes in thermal characteristics of PVA after mixing with GO particles. The composite samples exhibit a significant finding at different concentrations and size distribution of GO.

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Tian, Hong Yan, Yue Hui Wang, Chun Liu i Kui Niu. "Preparation, Characterization and Physical Properties of Polyvinyl Alcohol-Layered Clay Nanocomposites". Advanced Materials Research 997 (sierpień 2014): 433–37. http://dx.doi.org/10.4028/www.scientific.net/amr.997.433.

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This work focused on the preparation of poly (vinyl alcohol) (PVA)/ layered double hydroxide (LDH) and LDHSA nanocomposites by casting method. The morphology and interlayer spacing of the composites were characterized. The mechanical properties and the photochemical stability of the film of PVA, PVA/LDH and PVA/LDHSA have been studied and compared with PVA/MMT nanocomposites reported in previously. The results indicated that the thermal stability and dynamic mechanical properties of the PVA matrix in the PVA/LDH films and PVA/MMT films was enhanced. PVA/LDH films and PVA/OMMT films were shown stable photochemically more than those of pure PVA.

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Allel, Amina, Mohamed Wahib Naceur, Hassiba Benguergoura, Alain Ledoux, Waseem Sharaf Saeed, Abdel-Basit Al-Odayni i Taïeb Aouak. "Pervaporative separation of water–ethanol mixtures using an Algerian Na+ montmorillonite nanoclay-incorporated poly(vinyl alcohol) nanocomposite membrane". RSC Advances 10, nr 65 (2020): 39531–41. http://dx.doi.org/10.1039/d0ra07265f.

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This work aims to study the role of bentonite, Na⁺ montmorillonite (Na⁺MMT), as a filler to design a new poly(vinyl alcohol) (PVA)-based membrane for the pervaporation of an azeotropic water/ethanol mixture to enhance its separation efficiency.

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Bozkurt, Ayhan, i Ayşe Aslan. "As an Alternative Membrane: Functional NanoParticles/Polymer Composites Membranes for Proton Exchange Membrane Fuel Cells (PEMFC)". Advanced Materials Research 716 (lipiec 2013): 98–102. http://dx.doi.org/10.4028/www.scientific.net/amr.716.98.

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Novel proton conducting nanocomposite membranes included binary and ternary mixtures of acid modified nanotitania particles particles with polymers such as poly (vinyl alcohol) (PVA),pol (vinyl phosphonic acid), sulfonated polysulfone (SPSU) and poly (1-vinyl 1,2,4-triazole) (PVTri) . The interaction of functional nanoparticles with the host matrix were searched by FT-IR spectroscopy. The homogeneous distribution of functional nanoparticles in the membranes was confirmed by SEM micrographs. The spectroscopic measurements and water/methanol uptake studies suggested a complexation between polymers and sulphonic acid that inhibited the leaching out of acidic units. The TGA results verified that the presence of modified nanoparticles in the composite membranes the thermel stability of the membranes enhanced up to above 200 °C.

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Artykuły w czasopismach na temat „(poly)vinyl Alcohol(PVA) Nanocomposite”

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