Thermal and Mechanical Properties of Cellulose Nanofibers Reinforced Polyvinyl Alcohol Composite Films (original) (raw)
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International Journal of Engineering
This paper presents an experimental study of addition of cellulose nanofibers (CNF) extracted by the chemical-ultrasonication process from agave cantala leaf plants in the matrix of polyvinyl alcohol (PVA). Combining these materials produce the nanocomposite film with a thickness of 30 μm. The nanocomposite characteristic was investigated by the addition of CNF (0, 2, 5, 8, and 10 wt%) in PVA suspension (3 wt.%). PVA/CNF nanocomposite films were prepared by a casting solution method. The fibrillation of fibers to CNF was analyzed using Scanning Electron Microscopy and Transmission Electron Microscopy. The nanocomposite film functional group's molecular chemical bond and structural analysis were tested using Fourier Transform Infrared and X-ray diffraction. The PVA/CNF nanocomposite film has significant advantages on the ultraviolet barrier, thermal stability tested by Differential Scanning Calorimetry and Thermogravimetric Analyzer, and tensile strength. Overall, the optimal addition of CNF is 8 wt.% in matrix, resulting in the highest crystallinity index (37.5%), the tensile strength and elongation at break was an increase of 79% and 138%, respectively. It has good absorbing ultraviolet rays (82.4%) and high thermal stability (365 o C).
Utilization of Cellulose from Pineapple Leaf Fibers as Nanofiller in Polyvinyl Alcohol-Based Film
Indonesian Journal of Chemistry, 2016
Cellulose from pineapple leaf fibers as one of the natural polymer which has biodegradable property in a nanometer’s scale, can be formed as a filler in composite of Poly(vinyl) Alcohol/PVA is expected to increase the physical, thermal, and barrier properties of composite films similar to conventional plastic. The aim of this study was to examine the effect of fibrillation of cellulose fibers from pineapple leaf fibers using a combined technique of chemical-mechanical treatments, to investigate the reinforcing effect of concentration of nanocellulose fibrils in the polyvinyl alcohol (PVA) matrix on physical properties, thermal properties, water vapor transmission rate, light transmittance and morphological with and without addition of glycerol. Nanocellulose was made from cellulose of pineapple leaf fiber using wet milling (Ultra Fine Grinder). The composite film production was carried out by using casting solution method by mixing PVA solution with nanocellulose (10-50%) and glyce...
Polymers, 2020
The present work aims to combine the unique properties of cellulose nanofibers (CNF) with polyvinyl alcohol (PVA) to obtain high-performance nanocomposites. CNF were obtained by means of TEMPO-mediated ((2,2,6,6-Tetramethylpiperidin-1-yl)oxyl) oxidation, incorporated into the PVA matrix by means of compounding in a single-screw co-rotating internal mixer and then processed by means of injection molding. It was found that CNF were able to improve the tensile strength of PVA in 85% when 4.50 wt % of CNF were added. In addition, the incorporation of a 2.25 wt % of CNF enhanced the tensile strength to the same level that when 40 wt % of microsized fibers (stone groundwood pulp, SGW) were incorporated, which indicated that CNF possessed significantly higher intrinsic mechanical properties than microsized fibers. SGW was selected as reference for microsized fibers due to their extended use in wood plastic composites. Finally, a micromechanical analysis was performed, obtaining coupling fa...
Plastics, Rubber and Composites, 2018
The work reported demonstrates an simple method of extracting cellulose nanofibers (CNF) from cellulose microfibers (CMF) obtained from the plant Stipatenacissima. Here, a method for the production of CNF from CMF extracted from Alfa grass by exfoliation in polyvinyl alcohol (PVA) solution, is demonstrated. The CMF were produced in powder form and exfoliated in PVA aqueous solution to produce composites with 2, 4, 5 and 10 wt-% of CNF. Scanning Electron Microscopy demonstrated exfoliation of CMF, dispersion of the CNF and wetting by the polymer. The composites were characterised by thermogravimetry, differential scanning calorimetry, X-ray diffraction and tensile testing. The addition of CNF to PVA reduced the crystallinity degree of PVA. The large increase of the Young's modulus from 38 to 113% (relative to pure PVA) for composites with 2 to 10 wt-% of CNF incorporation is consistent with the extensive exfoliation of CMF into CNF and its excellent interface with PVA.
Journal of Natural Fibers, 2020
Due to a high aspect ratio and enhanced mechanical strength, cellulose nanofibrils can be used as reinforcing elements in biocomposite films. In this study, cellulose nanofibrils were isolated from sugarcane bagasse using TEMPO-mediated oxidation and used to reinforce polyvinyl alcohol (PVA) films. The carboxyl group content, functional groups, crystallinity, thermal properties, and morphology of the nanofibrils were investigated. The influence of TOCNF content on the transmittance, swelling, and tensile strength of PVA-TOCNF films were investigated by varying the TOCNF content of PVA films. The fibrils had a carboxyl content of 12.2 ± 0.6 mg/g CE due to the presence of carboxylic groups, an increased degree of crystallinity, and highly porous nanofibrils with lengths between 150 nm and 600 nm. Incorporation of the isolated fiber on PVA films increased the swelling capacity, tensile strength, and UV absorption but a decrease in the solubility of the composite. An increase in the TOCNF content increased the tensile strength of the films with the highest tensile strength of 6.6 ± 2.2 kPa being observed when the TOCNF content was 30%. The improvement in films properties implies that the films can be used as a packaging material due to enhanced water absorption and light-barrier properties.
IOP Publishing, 2019
This research was aimed to manufacture polyvinyl alcohol (PVA)/ cellulose nanofiber (CNF) nanocomposite which was isolated from oil palm empty fruit bunches (OPEFB) through steam explosion method combined with a hydrolysis process involving HCl 10%. The isolation process was performed in 2 steps; α-cellulose isolation from empty fruit bunches fibers and then cellulose nanofiber isolation from α-cellulose which was hydrolyzed with acid using ultrasonicator and homogenized in rotational speed of 8000 rpm. The functional group and morphology of nanofibres cellulose were characterized. FT-IR spectrum resulted an absorptions for CO -C group at wavelength of 1059.99 cm-1 which indicated a glycoside bond. Then, C-H group at 2900.94 cm-1 and O-H group at 3348.62 cm-1 were revealed to indicate the cellulose nanofiber. Moreover, TEM was used for morphological analysis and showing a decrease in fibres diameters after experiencing a chemical-mechanical treatment which lead to nanofibres with final diameter size of 20-30 nm. PVA/CNF nanocomposite with the percentage ratio of 80:20 gave a tensile strength of 17.41 Mpa and Modulus Young of 0.9 Gpa. Finally, the product was also morphologically analyzed with SEM and indicating an even distribution on the PVA surface.
Processing of Cellulose Nanofiber-reinforced Composites
Journal of Reinforced Plastics and Composites, 2005
Cellulose nanofibers are obtained from various sources such as flax bast fibers, hemp fibers, kraft pulp, and rutabaga, by chemical treatments followed by innovative mechanical techniques. The nanofibers thus obtained have diameters between 5 and 60 nm. The ultrastructure of cellulose nanofibers is investigated by atomic force microscopy and transmission electron microscopy. The cellulose nanofibers are also characterized in terms of crystallinity. Reinforced composite films comprising 90% polyvinyl alcohol and 10% nanofibers are also prepared. The comparison of the mechanical properties of these composites with those of pure PVA confirmed the superiority of the former.
International Journal of Polymer Science
Thermoplastic starch-polyvinyl alcohol composite films were prepared by casting method with cellulose nanofibers as reinforcement agent and glycerol as plasticizer. The obtained cellulose nanofibers with a diameter of 27.23±8.21 nm were isolated from oil palm empty fruit bunches (OPEFBs) by mechanical treatment. The addition of cellulose nanofibers until 3 wt% increased tensile strength and crystallinity of the composite films. In contrast, it decreased their elongation at break and water vapor transmission rate. Meanwhile, the addition of glycerol increased elongation at break and water vapor transmission rate of film matrix but lowers tensile strength of composite films.
PREPARATION AND CHARACTERIZATION OF NANOFIBRILLATED CELLULOSE/POLY (VINYL ALCOHOL) COMPOSITE FILMS
Poly (vinyl alcohol) based composite films with different loadings of cellulose nanofibrils were prepared using a solvent casting method and their tensile, optical and wettability properties were tested. The morphology of both neat poly (vinyl alcohol) and nanocomposites was explored by using a field emission scanning electron microscope technique. Results indicated that the tensile strength and Young's modulus of poly (vinyl alcohol) composite films were significantly improved with the increase of cellulose nanofibrils loading. However, the percentage of elongation at break decreased with increasing of cellulose nanofibrils. The films became increasingly opaque with increasing cellulose nanofibrils contents, although the composites also retained moderate transparency. The samples containing cellulose nanofibrils exhibited higher hydrophobicity compared with that of neat poly (vinyl alcohol). Field emission scanning electron microscope micrographs revealed that the cellulose nanofibrils were homogeneously dispersed in the poly (vinyl alcohol) matrix.
The objective of this study is to extract cellulose nanofibers (CNFs) from wheat straw and utilize them in thermoset polymers to improve their performance. CNFs were extracted from wheat straw by formic/peroxyformic acid treatment, hydrogen peroxide bleaching, followed by ball milling. To ensure better interaction between CNFs and epoxy polymer matrix, surface of CNFs was chemically modified by silane treatment. Furthermore, surface treated CNFs were added in varying proportion (1, 2 and 3 %) to an epoxy polymer to fabricate polymer composites. The chemical reaction and structural analysis was evaluated by FTIR analysis. Incorporation of CNFs into matrix increased flexure strength, flexure modulus, storage modulus, glass transition temperature and decomposition temperatures. Maximum improvement was observed for 2 % loading of CNFs as it facilitates maximum crosslinking with epoxy polymers. Maximum improvement in flexure strength and modulus of 22.5 % and 31.7 %, respectively was obtained by the addition of 2 % CNFs. Furthermore, storage modulus was 22.3 % higher than neat epoxy for 2 % loading of CNFs at room temperature, while T g improved by 18 %. Thermal stability of composite was improved probably due to the catalytic effect of CNFs. Cellulose nanofibers (CNFs) enhanced both first and second decomposition temperatures by up to 19 and 14 °C, respectively over neat system.