scholarly journals Effects of Two Different Cellulose Nanofiber Types on Properties of Poly(vinyl alcohol) Composite Films

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Kitti Yuwawech ◽  
Jatuphorn Wootthikanokkhan ◽  
Supachok Tanpichai
Keyword(s):  
Fiber Type ◽  
Cellulose Nanofibers ◽  
Composite Films ◽  
Cellulose Nanofiber ◽  
Ductile Deformation ◽  
Nanocomposite Films ◽  
Light Transmittance ◽  
Poly Vinyl Alcohol ◽  
Fiber Types ◽  
Sem Images

This work concerns a study on the effects of fiber types and content of cellulose nanofiber on mechanical, thermal, and optical properties polyvinyl alcohol (PVA) composites. Two different types of cellulose nanofibers, which are nanofibrillated cellulose (NFC) and bacterial cellulose (BC), were prepared under various mechanical treatment times and then incorporated into the PVA prior to the fabrication of composite films. It was found that tensile modulus of the PVA film increased with nanofibers content at the expense of its percentage elongation value. DSC thermograms indicate that percentage crystallinity of PVA increased after adding 2–4 wt% of the fibers. This contributed to the better mechanical properties of the composites. Tensile toughness values of the PVA/BC nanocomposite films were also superior to those of the PVA/NFC system containing the same fiber loading. SEM images of the composite films reveal that tensile fractured surface of PVA/BC experienced more ductile deformation than the PVA/NFC analogue. The above discrepancies were discussed in the light of differences between the two types of fibers in terms of diameter and their intrinsic properties. Lastly, percentage total visible light transmittance values of the PVA composite films were greater than 90%, regardless of the fiber type and content.

Preparation and Characterization of Cellulose Nanofiber/Zinc Oxide Composite Films

2020 ◽  
Vol 14 (2) ◽  
pp. 203-208 ◽  
Author(s):  
Xiuqiang Zhang ◽  
Suxia Ren ◽  
Xiaofeng He ◽  
Lili Dong ◽  
Wei Bai ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Zno Nanoparticles ◽  
Biomedical Applications ◽  
Cellulose Nanofibers ◽  
Composite Films ◽  
Cellulose Nanofiber ◽  
Nanocomposite Films ◽  
Zno Films ◽  
X Ray Diffraction

Zinc oxide (ZnO)/cellulose nanofiber (CNF) nanocomposite films were prepared using cellulose nanofibers and ZnO nanoparticles. First, suspensions of CNF and ZnO mixtures were blended with different CNF/ZnO ratios; then, the mixtures were stirred, homogenized, filtered, and hot pressed to form nanofilms with various ZnO weight ratios (0–50 wt%). Rheological tests showed that the CNF shear thinning behavior was not affected by the addition of ZnO. X-ray diffraction and scanning electron microscopy studies proved the existence of ZnO nanoparticles in the nanocomposite films. Thermogravimetric results indicated that the presence of ZnO had almost no effect on the thermal properties of the composite. As the ZnO content increased, the tensile strength and strain-to-failure rate decreased. In comparison with neat CNF nanofilms, the nanocomposite films showed greater antimicrobial ability against Gram-positive Staphylococcus aureus due to the presence of ZnO nanoparticles, allowing the CNF/ZnO films to be used in some targeted biomedical applications.

Fiber Orientation Control by Stretching in Cellulose Nanofiber Green Composites

2017 ◽  
Vol 754 ◽  
pp. 135-138
Author(s):  
Hitoshi Takagi ◽  
Antonio Norio Nakagaito ◽  
Yuya Sakaguchi
Keyword(s):  
Fiber Orientation ◽  
Vinyl Alcohol ◽  
Glass Fibers ◽  
Cellulose Nanofibers ◽  
Polymeric Composite ◽  
High Strength ◽  
Sample Surface ◽  
Cellulose Nanofiber ◽  
Poly Vinyl Alcohol ◽  
Nanofiber Alignment

The presence of nanoscale cellulosic fiber; namely cellulose nanofiber, increases year by year because the mechanical and physical properties are believed to be comparable to those of common glass fibers. On the other hand, most of the reported strength data for the cellulose nanofiber-reinforced polymeric composite materials was not as high as expected. In order to obtain high-strength cellulose nanofiber-reinforced polymer composites, we tried to optimize the fiber orientation of cellulose nanofibers in poly (vinyl alcohol)-based polymer matrix by using a repeated mechanical stretching treatment. The fiber orientation of cellulose nanofibers in the poly (vinyl alcohol) matrix can be modified by changing the total amount of stretching strain applied during the multiple stretching treatments. The degree of fiber alignment was directly evaluated by observing the cellulose nanofibers on the sample surface with a digital microscope. The efficacy of proposed nanofiber alignment control has been explored experimentally and theoretically. The tensile strength and modulus of the cellulosic nanocomposites after applying the multiple stretching treatments increased by approximately 80% and 40% respectively, as compared with those of the untreated nanocomposites.

scholarly journals Preparation and Assessment of Heat-Treated α-Chitin Nanowhiskers Reinforced Poly(viny alcohol) Film for Packaging Application

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1883 ◽  
Author(s):  
Chao Peng ◽  
Guangxue Chen
Keyword(s):  
Heat Treatment ◽  
Composite Films ◽  
Barrier Properties ◽  
Mechanical Tests ◽  
Light Transmittance ◽  
Poly Vinyl Alcohol ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Chitin Nanowhiskers

In this study, poly(vinyl alcohol) (PVA) composite films enhanced by α-chitin nanowhiskers (ChWs) were prepared through heat treatment. The obtained membranes were assessed by means of FTIR spectroscopy, X-ray diffraction, thermogravimetric analysis, regular light transmittance, mechanical tests, permeability and water absorption. The influence of the nano-component and heat treatment on the mechanical, thermal and water-resistant properties of the composite membrane were analyzed. From the results of the work, the produced films with excellent barrier properties and inexpensive raw processed materials have great prospects in packaging applications.

scholarly journals Biocomposites from Rice Straw Nanofibers: Morphology, Thermal and Mechanical Properties

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2138 ◽  
Author(s):  
José Carlos Alcántara ◽  
Israel González ◽  
M. Mercè Pareta ◽  
Fabiola Vilaseca
Keyword(s):  
Rice Straw ◽  
Mechanical Performance ◽  
Cellulose Nanofibers ◽  
Nucleating Agent ◽  
Mechanical Analysis ◽  
Nanocomposite Films ◽  
Chemical Extraction ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
The Matrix

Agricultural residues are major potential resources for biomass and for material production. In this work, rice straw residues were used to isolate cellulose nanofibers of different degree of oxidation. Firstly, bleached rice fibers were produced from the rice straw residues following chemical extraction and bleaching processes. Oxidation of rice fibers mediated by radical 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) at pH 10 was then applied to extract rice cellulose nanofibers, with diameters of 3–11 nm from morphological analysis. The strengthening capacity of rice nanofibers was tested by casting nanocomposite films with poly(vinyl alcohol) polymer. The same formulations with eucalyptus nanofibers were produced as comparison. Their thermal and mechanical performance was evaluated using thermogravimetry, differential scanning calorimetry, dynamic mechanical analysis and tensile testing. The glass transition of nanocomposites was shifted to higher temperatures with respect to the pure polymer by the addition of rice cellulose nanofibers. Rice nanofibers also acted as a nucleating agent for the polymer matrix. More flexible eucalyptus nanofibers did not show these two phenomena on the matrix. Instead, both types of nanofibers gave similar stiffening (as Young’s modulus) to the matrix reinforced up to 5 wt.%. The ultimate tensile strength of nanocomposite films revealed significant enhancing capacity for rice nanofibers, although this effect was somehow higher for eucalyptus nanofibers.

Electrochemical synthesis and properties of layer-structured polypyrrole/montmorillonite nanocomposite films

2010 ◽  
Vol 25 (4) ◽  
pp. 658-664 ◽  
Author(s):  
Chang-An Wang ◽  
Keyu Chen ◽  
Yong Huang ◽  
Huirong Le
Keyword(s):  
Deposition Time ◽  
Composite Films ◽  
Nanocomposite Films ◽  
Nanoindentation Test ◽  
Test Results ◽  
X Ray Diffraction ◽  
Free Standing ◽  
Sem Images ◽  
X Ray ◽  
Scanning Electron

Layer-structured polypyrrole/montmorillonite (PPy/MMT) naoncomposite films were synthesized by the electrodeposition method. The fabricated free-standing films consist of about 0∼2 wt% Na+-montmorillonite (NMMT). The thickness of films could be controlled by deposition time. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to observe the microstructure of the films. After MMT was introduced into the PPy matrix, the interspace between PPy chains decreased, according to the XRD results. The layered structure of the films was observed from the SEM images. Tensile and nanoindentation test results showed that the mechanical properties of the composite films were improved at low clay loading. The electrical conductivity of the films with 1.2 wt% MMT loading was increased from 3.6 to 51 S/cm, probably because of the restricted growth of PPy chains in the interspace of MMT layers.

Rice Straw Extracted Cellulose Biocompatible Nanofiber

2017 ◽  
Vol 6 (2) ◽  
pp. 1-20
Author(s):  
Matoore Lamani
Keyword(s):  
Rice Straw ◽  
Cellulose Nanofibers ◽  
Control Sample ◽  
Volumetric Flow Rate ◽  
Average Diameter ◽  
Solid Content ◽  
Cellulose Nanofiber ◽  
Diameter Distribution ◽  
Human Skin Fibroblast ◽  
Sem Images

This article focuses on the electrospinning of nanofibers from rice straw as a renewable, cheap natural resource. To facilitate the formation of cellulose nanofiber, PVA was utilized as a secondary plasticizing polymer. The polymer solution contained 75% w/w cellulose and 25% w/w PVA using water/formic acid solvent resulting in 8% w/w solid content was successfully prepared as spinning solution. According to SEM images, temperature and voltage have significant impact in producing continuous cellulose nanofibers without beads. A microscopic observation reveals the formation of nanofiber with an average diameter of 177 ± 25 nm. This narrow diameter distribution is a direct outcome of temperature, voltage, volumetric flow rate and tip to collector distance adjustment respectively on 60, 25 kv, 1 µl/hr and 10 cm. The biocompatibility tests using human skin fibroblast cell culture demonstrate the nontoxicity of cellulose nanofiber scaffold compared to a control sample.

Polymer nanocomposites reinforced with C60 fullerene: effect of hydroxylation

2011 ◽  
Vol 45 (25) ◽  
pp. 2595-2601 ◽  
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.

scholarly journals Dielectric Properties of Polyvinyl Alcohol/ Polyacrylamide Blend Film Filled with Carbon Nanospheres

2021 ◽  
Author(s):  
Rashmi Adoor ◽  
Narasimha Ayachit ◽  
Kishor Upadhyaya ◽  
R.F. Bhajantri ◽  
Mallikarjun Anandalli
Keyword(s):  
Dielectric Properties ◽  
Polyvinyl Alcohol ◽  
Composite Films ◽  
Nanocomposite Films ◽  
Carbon Nanospheres ◽  
High Increase ◽  
Sem Images ◽  
Xrd Pattern ◽  
Solution Casting Method ◽  
Energy Storage Efficiency

Abstract Carbon nanosphere / Polyvinyl alcohol/Polyacrylamide (CNS/PVA/PAM) nanocomposite films prepared via a solution casting method were studied for their structural and dielectric properties. Scanning Electron Microscopy (SEM) images of the CNS/PVA/PAM blends reveal the formation of circular islands of CNS and uniform blending with PVA/PAM matrix. XRD pattern shows a higher value with increase in blending ratio of PVA with CNS. The interaction of the dispersed and preformed CNS particles with the PVA/PAM chain was confirmed by the corresponding vibrational signaturing of PVA/PAM through FTIR. The dielectric constant increased from [K = 134, 2K Hz, 305 Kelvin] to [K = 438, 2KHz, 333 Kelvin] and the composite films exhibited a high increase in the energy storage efficiency upto 75% (at 2KHz) in the case of 4%CNS /PVA/PAM 50:50 sample.

scholarly journals Preparation, Properties and Mechanism of Anionic and Cationic CNC/WPU Composite Films

2021 ◽  
Author(s):  
Ya-Yu Li ◽  
Yan-Ru Bai ◽  
Xin-Qian Zhang ◽  
Xin Liu ◽  
Zhen Dai ◽  
...  
Keyword(s):  
Composite Film ◽  
Food Packaging ◽  
Composite Films ◽  
Interaction Mechanism ◽  
Water Vapor Permeability ◽  
Waterborne Polyurethane ◽  
Barrier Properties ◽  
Nanocomposite Films ◽  
Light Transmittance ◽  
Vapor Permeability

Abstract Three kinds of cellulose nanocrystals (CNCs) were added into waterborne polyurethane (WPU), and nanocomposite films were prepared by solution casting method. The influence of different ionic function groups on microstructure and properties of composite films was investigated, and interaction mechanism between these two components was analyzed. Results show that thermal stability of these composite films are improved by 15℃. Compared with sulfated CNCs （SCNCs） and TEMPO oxidized CNCs (TOCNCs), FE-SEM results prove that cationized CNCs (CaCNCs) have better dispersion in composite films. In addition, fracture surface did not display large cavities, which indicates the interface binding force between WPU and CaCNCs is stronger. The tensile strength and fracture work of CaCNC/WPU composite film increase by 11.9% and by 8.4%, respectively. The oxygen permeability of CaCNC/WPU composite film is the lowest in these composite films, which is 5.00 cm3•cm (cm2•s•Pa)-1. Water vapor permeability of composite films may have a close positive correlation with their hygroscopicity. In all, composite film with CaCNCs has optimal strength, toughness, light transmittance and oxygen barrier properties. There may be opposite ion attraction superimposed hydrogen bond between CaCNCs and WPU in the composite film. The composite films are expected to have applications in food packaging, furniture coatings and biomedical applications.

Novel Poly (vinyl Alcohol) Nanocomposites Reinforced with Nano Cellulose Fibrils Isolated from Plants by Mechanochemical Treatment

2012 ◽  
Vol 174-177 ◽  
pp. 870-876 ◽  
Author(s):  
Yue Hu ◽  
Da Gang Li ◽  
Qiao Yun Deng ◽  
Yu Mei Wang ◽  
Dong Liang Lin
Keyword(s):  
Alkali Treatment ◽  
Cellulose Nanofibers ◽  
Testing Machine ◽  
Mechanochemical Treatment ◽  
Nanocomposite Films ◽  
Poly Vinyl Alcohol ◽  
Immersion Method ◽  
Tensile Testing Machine ◽  
Cellulose Fibrils ◽  
Nano Cellulose

The objective of this study was to reinforce biodegradable polyvinyl alcohol (PVA) with nano cellulose fibrils generated from poplar and cotton through mechanochemical treatment. A method used a combination of acid and alkali treatment to obtain cellulose from poplar and cotton. The cellulose of both fibers was further processed by grinder treatment. PVA/nano cellulose composite was prepared successfully by an immersion method. The cellulose nanofibers and nanocomposite films were characterized with scanning electron microscope (SEM), tensile testing machine, ultraviolet-visible spectrophotometry (UV-vis). SEM showed the diameter of the cellulose was range between 30-100 nm and exhibited a high aspect ratio of over 1500. The mechanical properties of PVA were improved significantly and the two plant nanofibers had the similarly reinforcing effects in the matrix. Cellulose nanofibers as a future resource have tremendous potential since they are one of the most abundant organic resources on the earth.

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