Fabrication and Characterization of Nanocomposite Flexible Membranes of PVA and Fe3O4

Composite polymer membranes of poly(vinyl alcohol) (PVA) and iron oxide (Fe3O4) nanoparticles were produced in this work. X-ray diffraction measurements demonstrated the formation of Fe3O4 nanoparticles of cubic structures. The nanoparticles were synthesized by a coprecipitation technique and added to PVA solutions with different concentrations. The solutions were then used to generate flexible membranes by a solution casting method. The size and shape of the nanoparticles were investigated using scanning electron microscopy (SEM). The average size of the nanoparticles was 20±9 nm. Raman spectroscopy and Fourier-transform infrared spectroscopy (FTIR) were utilized to investigate the structure of the membranes, as well as their vibration modes. Thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) demonstrated the thermal stability of the membranes and the crystallinity degree. Electrical characteristics of the thin membranes were examined using impedance spectroscopy as a function of the nanoparticles’ concentrations and temperatures. The resistivity of the fabricated flexible membranes was possible to adjust by controlled doping with suitable concentrations of nanoparticles. The activation energy decreased with the nanoparticles’ concentrations due to the increase in charge carriers’ concentrations. Therefore, the fabricated membranes may be applied for practical applications that involve the recycling of nanoparticles for multiple application cycles.

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Study on Structure, Thermal Behavior, and Viscoelastic Properties of Nanodiamond-Reinforced Poly (vinyl alcohol) Nanocomposites

Polymers ◽

10.3390/polym13091426 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1426

Author(s):

Tomáš Remiš ◽

Petr Bělský ◽

Tomáš Kovářík ◽

Jaroslav Kadlec ◽

Mina Ghafouri Azar ◽

...

Keyword(s):

Electron Microscopy ◽

Mechanical Analysis ◽

Single Step ◽

Poly Vinyl Alcohol ◽

Scanning Calorimetry ◽

X Ray Scattering ◽

Transmission Electron ◽

Primary Particles ◽

Solution Casting Method ◽

Average Size

In this work, advanced polymer nanocomposites comprising of polyvinyl alcohol (PVA) and nanodiamonds (NDs) were developed using a single-step solution-casting method. The properties of the prepared PVA/NDs nanocomposites were investigated using Raman spectroscopy, small- and wide-angle X-ray scattering (SAXS/WAXS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). It was revealed that the tensile strength improved dramatically with increasing ND content in the PVA matrix, suggesting a strong interaction between the NDs and the PVA. SEM, TEM, and SAXS showed that NDs were present in the form of agglomerates with an average size of ~60 nm with primary particles of diameter ~5 nm. These results showed that NDs could act as a good nanofiller for PVA in terms of improving its stability and mechanical properties.

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Study of the compounding process parameters for morphology control of LDPE/layered silicate nanocomposites

e-Polymers ◽

10.1515/epoly.2009.9.1.606 ◽

2009 ◽

Vol 9 (1) ◽

Author(s):

Serena Coiai ◽

Marco Scatto ◽

Monica Bertoldo ◽

Lucia Conzatti ◽

Leonardo Andreotti ◽

...

Keyword(s):

Thermo Gravimetric Analysis ◽

Layered Silicate ◽

Gravimetric Analysis ◽

Scanning Calorimetry ◽

Neat Polymer ◽

Crystallinity Degree ◽

Melt Compounding ◽

Twin Screw ◽

Organo Clay ◽

Clay Platelets

AbstractA careful insight into melt compounding procedure is proposed in order to achieve a better understanding and control of the dispersion and orientation mechanisms of organo-clay platelets into LDPE nanocomposites. The method involved is the preparation of a maleic anhydride grafted polyethylene masterbatch containing 10 wt% organo-clay via twin-screw extrusion. A substantial nanodispersion and orientation of clay platelets was obtained as observed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses. Moreover, the nanocomposites prepared by diluting the master-batch through the blend mixing with additional LDPE preserved or improved the exfoliation and lamellae orientation. Finally, the thermo-gravimetric analysis (TGA) showed a significant improvement of the thermal stability while both differential scanning calorimetry (DSC) and XRD evidenced a slight increase of the LDPE crystallinity degree with respect to neat polymer matrices thus suggesting the occurrence of orientation also for the polymer.

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Lipase mediated synthesis of polycaprolactone and its silica nanohybrid

Pure and Applied Chemistry ◽

10.1515/pac-2018-1011 ◽

2019 ◽

Vol 91 (6) ◽

pp. 957-965

Author(s):

Meltem Akkulak ◽

Yasemin Kaptan ◽

Yasar Andelib Aydin ◽

Yuksel Avcibasi Guvenilir

Keyword(s):

Average Molecular Weight ◽

Proton Nuclear Magnetic Resonance ◽

Gravimetric Analysis ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Structural Investigations ◽

Crystallinity Degree ◽

Molecular Weights ◽

H Nmr

Abstract In this study, rice husk ash (RHA) silanized with 3-glycidyloxypropyl trimethoxysilane was used as support material to immobilize Candida antarctica lipase B. The developed biocatalyst was then utilized in the ring opening polymerization (ROP) of ε-caprolactone and in situ development of PCL/Silica nanohybrid. The silanization degree of RHA was determined as 4 % (w) by thermal gravimetric analysis (TGA). Structural investigations and calculation of molecular weights of nanohybrids were realized by proton nuclear magnetic resonance (1H NMR). Crystallinity was determined by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Scanning Electron Microscopy (SEM) was used for morphological observations. Accordingly, the PCL composition in the nanohybrid was determined as 4 %, approximately. Short chained amorphous PCL was synthesized with a number average molecular weight of 4400 g/mol and crystallinity degree of 23 %. In regards to these properties, synthesized PCL/RHA composite can find use biomedical applications.

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Polymer nanocomposites reinforced with C60 fullerene: effect of hydroxylation

Journal of Composite Materials ◽

10.1177/0021998311416682 ◽

2011 ◽

Vol 45 (25) ◽

pp. 2595-2601 ◽

Cited By ~ 12

Author(s):

Tsuyoshi Saotome ◽

Ken Kokubo ◽

Shogo Shirakawa ◽

Takumi Oshima ◽

H. Thomas Hahn

Keyword(s):

Thermal Stability ◽

Thermo Gravimetric Analysis ◽

Nanocomposite Films ◽

Light Transmittance ◽

C60 Fullerene ◽

Partial Hydrolysis ◽

Poly Vinyl Alcohol ◽

Gravimetric Analysis ◽

Scanning Calorimetry ◽

Thermal Stability Of

Novel nanocomposite films of polycarbonate (PC) with fullerene derivatives, such as pristine fullerene C60 and polyhydroxylated-fullerenes, C60(OH)12 and C60(OH)36, were prepared. The optical, thermal, and mechanical properties of the composites were measured. Nanocomposite films of poly (vinyl alcohol) (PVA) with C60(OH)36 were prepared as a reference to show how improved dispersion of the nanofiller affects the overall transparency of the composites. Ultraviolet-visible spectroscopy showed that the addition of hydroxylated fullerenes did not affect visible light transmittance of the films significantly in the range of 400–800 nm. Differential scanning calorimetry (DSC) and thermo–gravimetric analysis (TGA) measurements showed the increased thermal stability of PC/C60(OH)12 film as compared to pristine PC film. This phenomenon was explained by the rigid polymer interphase regions formed around C60(OH)12 due to the plausible hydrogen bonding and hydrophobic interaction. On the other hand, the lower thermal stability of PC–C60(OH)36 was assumed to be caused by large agglomeration of the C60(OH)36 particles and the partial hydrolysis of the polycarbonate matrix. Tensile testing of the composites showed reduction in elongation at break and yield tensile strength. These results may be caused by the particle agglomerations which act as the initiation points for cracks.

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Preparation, Characterization and Antibacterial Efficiency of Olive Leaves Extract and Chitosan-Silver Nanoparticles using Electrochemical Method

JOURNAL OF ADVANCES IN PHYSICS ◽

10.24297/jap.v15i0.8070 ◽

2019 ◽

Vol 15 ◽

pp. 6152-6164

Author(s):

Moustafa Tawfik Ahmed

Keyword(s):

Silver Nanoparticles ◽

Uv Spectroscopy ◽

Good Alternative ◽

Gravimetric Analysis ◽

X Ray Diffraction ◽

Olive Leaves ◽

Scanning Calorimetry ◽

Electrochemical Approach ◽

Vis Spectroscopy ◽

Average Size

The present work involves the improvement of chitosan-olive leaves extract and silver nanoparticles (Cs-OLE-AgNPs) using electrochemical approach followed by UV-irradiation reduction. The formation of silver nanoparticles (AgNPs) was characterized via UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), EDX, thermal gravimetric analysis (TGA) and Swelling. The obtained nanoparticles average size was 36.19 nm. UV Spectroscopy show increase of peaks at 320 and 345 nm indicate the formation of a large cluster of AgNPs. Cs-OLE and Cs-OLE-AgNPs also demon started a relativity high antibacterial against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria. AgNPs show broadspectrum antibacterial activity at lower concentration (0.56%) and may be regarded as a good alternative therapeutic approach in the future.

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Effect of different amounts of modified talc on the mechanical, thermal, and crystallization properties of poly(butylene succinate)

Journal of Polymer Engineering ◽

10.1515/polyeng-2013-0229 ◽

2014 ◽

Vol 34 (4) ◽

pp. 379-385 ◽

Cited By ~ 6

Author(s):

Bingxin Sun ◽

Chengzhi Chuai ◽

Si Luo ◽

Ying Guo ◽

Chunyang Han

Keyword(s):

Thermal Stability ◽

Mechanical Test ◽

Gravimetric Analysis ◽

Scanning Calorimetry ◽

Electron Microscopic ◽

Butylene Succinate ◽

Crystallinity Degree ◽

Crystallization Properties ◽

Twin Screw ◽

Microscopic Studies

Abstract Poly(butylene succinate) (PBS) with different ratios of modified talc was prepared by twin-screw extruding. The effect of different loading amounts of talc on the mechanical, thermal, and crystallization properties of PBS was investigated. The mechanical test results indicate that the stiffness of the composites was increased linearly with increasing talc content, and the tensile strength and elongation stayed at relatively high levels when the talc amount is <15 phr. Thermal gravimetric analysis showed that the thermal stability of PBS composites was improved notably with a small amount (5–10 phr) of talc; however, high loading of talc did not help further improve the thermal stability. Differential scanning calorimetry data showed that the melting enthalpy (ΔHm), crystallization enthalpy (ΔHc), and crystallinity degree (Xc) decreased when the talc increased and crystallization temperature (Tc) was moving to relatively high values. The results of X-ray diffraction demonstrated that the incorporation of talc inhibited the PBS crystallization behavior significantly but did not change the crystal structure. Scanning electron microscopic studies indicated that the homogeneous dispersion and smoother fracture surfaces of the composite became inhomogeneous and coarse with higher talc loading.

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Properties and structural characterization of chitosan/poly(vinyl alcohol)/graphene oxide nano composites

e-Polymers ◽

10.1515/epoly.2012.12.1.386 ◽

2012 ◽

Vol 12 (1) ◽

Cited By ~ 5

Author(s):

Jun Ma ◽

Changhua Liu ◽

Rui Li ◽

Jia Wang

Keyword(s):

Graphene Oxide ◽

Vinyl Alcohol ◽

Tensile Testing ◽

Nanocomposite Films ◽

Poly Vinyl Alcohol ◽

Gravimetric Analysis ◽

Scanning Calorimetry ◽

Force Microscopy ◽

Atomic Force ◽

Uniform Dispersion

AbstractChitosan (CS)/poly(vinyl alcohol) (PVA)/graphene oxide (GO) nanocomposites in the form of films are prepared in a casting and solvent evaporation method. Fourier-transform infrared spectroscopy (FTIR), X-ray diffractions (XRD), atomic force microscopy (AFM), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), tensile testing and moisture uptake were used to study the structure and properties of these chitosan/poly(vinyl alcohol) /graphene oxide (PCS/GO-n) nanocomposites. The result from tensile testing indicated that the nanocomposite containing 2 wt% GO exhibits high tensile strength (71.21 MPa) with a large elongation at break (51.8%). The high mechanical properties of the nanocomposite films are mainly due to uniform dispersion of GO sheets in the polymer matrix and strong interfacial interactions among components.

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Fabrication of Magnetic Cenosphere Deposited with Fe3O4 Nanoparticles by Hydrothermal Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.750-752.2021 ◽

2013 ◽

Vol 750-752 ◽

pp. 2021-2025 ◽

Cited By ~ 1

Author(s):

Hui Zhang ◽

Jie Yao Song ◽

Jian Chao Zhan

Keyword(s):

Electron Microscope ◽

Spinel Phase ◽

Gravimetric Analysis ◽

Vibrating Sample Magnetometer ◽

Hydrothermal Conditions ◽

Scanning Calorimetry ◽

Transmission Electron ◽

Reaction Solution ◽

Average Size ◽

Thermal Stability Of

We prepared the magnetic cenospheres deposited with magnetite Fe3O4nanoparticles under hydrothermal conditions. The crystalline phase, magnetization properties, morphology, chemical composition and thermal stability of asobtained cenospheres are analyzed by Xray diffraction, vibrating sample magnetometer, scanning electron microscope, Xray energy dispersive spectroscope, transmission electron microscope, thermal gravimetric analysis and differential scanning calorimetry techniques. The results show that the inverse cubic spinel phase of Fe3O4nanoparticles with an average size 50 nm are synthesized, and synchronously deposited on cenosphere surface. As the thickness of Fe3O4coating increases, the saturation magnetization increases to some extent. The growth of Fe3O4nanoparticles can be controlled by adding ethanol to the reaction solution.

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Wastes from Agricultural Silage Film Recycling Line as a Potential Polymer Materials

Polymers ◽

10.3390/polym13091383 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1383

Author(s):

Jerzy Korol ◽

Aleksander Hejna ◽

Klaudiusz Wypiór ◽

Krzysztof Mijalski ◽

Ewelina Chmielnicka

Keyword(s):

Vinyl Acetate ◽

Thermal Performance ◽

Mechanical Performance ◽

Ethylene Vinyl Acetate ◽

Tensile Tests ◽

Solid Particles ◽

Polymer Materials ◽

Slight Reduction ◽

Scanning Calorimetry ◽

Crystallinity Degree

The recycling of plastics is currently one of the most significant industrial challenges. Due to the enormous amounts of plastic wastes generated by various industry branches, it is essential to look for potential methods for their utilization. In the presented work, we investigated the recycling potential of wastes originated from the agricultural films recycling line. Their structure and properties were analyzed, and they were modified with 2.5 wt % of commercially available compatibilizers. The mechanical and thermal performance of modified wastes were evaluated by tensile tests, thermogravimetric analysis, and differential scanning calorimetry. It was found that incorporation of such a small amount of modifiers may overcome the drawbacks caused by the presence of impurities. The incorporation of maleic anhydride-grafted compounds enhanced the tensile strength of wastes by 13–25%. The use of more ductile compatibilizers—ethylene-vinyl acetate and paraffin increased the elongation at break by 55–64%. The presence of compatibilizers also reduced the stiffness of materials resulting from the presence of solid particles. It was particularly emphasized for styrene-ethylene-butadiene-styrene and ethylene-vinyl acetate copolymers, which caused up to a 20% drop of Young’s modulus. Such effects may facilitate the further applications of analyzed wastes, e.g., in polymer film production. Thermal performance was only slightly affected by compatibilization. It caused a slight reduction in polyethylene melting temperatures (up to 2.8 °C) and crystallinity degree (up to 16%). For more contaminated materials, the addition of compatibilizers caused a minor reduction in the decomposition onset (up to 6 °C). At the same time, for the waste after three washing cycles, thermal stability was improved. Moreover, depending on the desired properties and application, materials do not have to go through the whole recycling line, simplifying the process, reducing energy and water consumption. The presented results indicate that it is possible to efficiently use the materials, which do not have to undergo the whole recycling process. Despite the presence of impurities, they could be applied in the manufacturing of products which do not require exceptional mechanical performance.

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Utilization of Birch Bark as an Eco-Friendly Filler in Urea-Formaldehyde Adhesives for Plywood Manufacturing

Polymers ◽

10.3390/polym13040511 ◽

2021 ◽

Vol 13 (4) ◽

pp. 511

Author(s):

Roman Réh ◽

Ľuboš Krišťák ◽

Ján Sedliačik ◽

Pavlo Bekhta ◽

Monika Božiková ◽

...

Keyword(s):

Bending Strength ◽

Urea Formaldehyde ◽

Formaldehyde Emission ◽

Birch Bark ◽

Gravimetric Analysis ◽

European Standard ◽

Scanning Calorimetry ◽

Wood Processing ◽

Fagus Sylvatica L ◽

Positive Effect

The potential of using ground birch (Betula verrucosa Ehrh.) bark as an eco-friendly additive in urea-formaldehyde (UF) adhesives for plywood manufacturing was investigated in this work. Five-ply plywood panels were fabricated in the laboratory from beech (Fagus sylvatica L.) veneers bonded with UF adhesive formulations comprising three addition levels of birch bark (BB) as a filler (10%, 15%, and 20%). Two UF resin formulations filled with 10% and 20% wheat flour (WF) were used as reference samples. The mechanical properties (bending strength, modulus of elasticity and shear strength) of the laboratory-fabricated plywood panels, bonded with the addition of BB in the adhesive mixture, were evaluated and compared with the European standard requirements (EN 310 and EN 314-2). The mechanical strength of the plywood with the addition of BB in the adhesive mixture is acceptable and met the European standard requirements. Markedly, the positive effect of BB in the UF adhesive mixture on the reduction of formaldehyde emission from plywood panels was also confirmed. Initially, the most significant decrease in formaldehyde release (up to 14%) was measured for the plywood sample, produced with 15% BB. After four weeks, the decrease in formaldehyde was estimated up to 51% for the sample manufactured with 20% BB. The performed differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and derivative thermogravimetry (DTG), also confirmed the findings of the study. As this research demonstrated, BB as a waste or by-product of wood processing industry, can be efficiently utilized as an environmentally friendly, inexpensive alternative to WF as a filler in UF adhesive formulations for plywood manufacturing.

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