scholarly journals Synthesis of cellulose from Acetobacter xylinum bacteria – application of making biocomposite based on polyvinyl alcohol/cellulose

2015 ◽  
Vol 18 (3) ◽  
pp. 114-124
Author(s):  
Hong Thi Thu Phan ◽  
Ngan Thi My Luong ◽  
Trung Tien Vu ◽  
Ho Thanh Pham ◽  
Huy Thuc Ha ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Polyvinyl Alcohol ◽  
Mechanical Strength ◽  
Bacterial Cellulose ◽  
High Concentration ◽  
Thermogravimetric Analyzer ◽  
Plastic Materials ◽  
New Material ◽  
Biological Films

Bacterial cellulose (BC) is characterized for its high purity, good mechanical strength, non-toxic and non-allergic. Therefore, BC was used in many applications, such as biological films, paper, textiles, electronics, and especially in the biomedical field. The aim of this study is to make a new material which has high thermal stability and mechanical strength by combining BC and two kinds of polyvinyl alcohol (PVA 127 and PVA Kuraray). In the current study, it was found that the structure of bacterial cellulose was changed when PVA at different concentrations was supplied in the bacterial culture. The dispersity of BC fibers and the density of PVA particles of the material increased with high concentration of PVA. As a masterbatch (a composite additive material), a preparation of BC/PVA 217 was mixed with PVA Kuraray, and the mixture was then placed into a mixing chamber of an electrically heated machine (Hakke, Germany) at 170C, 80 rpm for 15 min. The melting mixture was shaped by a Hydraulic shaping machine. The structure of the material was assessed by scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR). The thermal stability of the material was measured using a thermogravimetric analyzer, and its mechanical properties were also studied. The results showed that the compatibility of BC and PVA in PVA/BC material is relatively high due to intermolecular hydrogen bondings. The material showed better thermal stability than PVA only. Its mechanical properties were also improved. The finding suggests that the composites of bacterial cellulose and PVA could be good candidates for replacing traditional nonbiodegradable plastic materials.

scholarly journals Influence of High-Concentration LLDPE on the Manufacturing Process and Morphology of Pitch/LLDPE Fibres

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1099
Author(s):  
Salem Mohammed Aldosari ◽  
Muhammad A. Khan ◽  
Sameer Rahatekar
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tensile Modulus ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
High Concentration ◽  
Scanning Electron Microscope Study ◽  
High Concentrations ◽  
Thermal Stability Of

A high modulus of elasticity is a distinctive feature of carbon fibres produced from mesophase pitch. In this work, we expand our previous study of pitch/linear low-density polyethylene blend fibres, increasing the concentration of the linear low-density polyethylene in the blend into the range of from 30 to 90 wt%. A scanning electron microscope study showed two distinct phases in the fibres: one linear low-density polyethylene, and the other pitch fibre. Unique morphologies of the blend were observed. They ranged from continuous microfibres of pitch embedded in linear low-density polyethylene (occurring at high concentrations of pitch) to a discontinuous region showing the presence of spherical pitch nodules (at high concentrations of linear low-density polyethylene). The corresponding mechanical properties—such as tensile strength, tensile modulus, and strain at failure—of different concentrations of linear low-density polyethylene in the pitch fibre were measured and are reported here. Thermogravimetric analysis was used to investigate how the increased linear low-density polyethylene content affected the thermal stability of linear low-density polyethylene/pitch fibres. It is shown that selecting appropriate linear low-density polyethylene concentrations is required, depending on the requirement of thermal stability and mechanical properties of the fibres. Our study offers new and useful guidance to the scientific community to help select the appropriate combinations of linear low-density polyethylene/pitch blend concentrations based on the required mechanical property and thermal stability of the fibres.

scholarly journals Preparation of polyaniline-polyvinyl alcohol-silver nanocomposite and characterization of its mechanical and antibacterial properties

2018 ◽  
Vol 25 (5) ◽  
pp. 975-982 ◽  
Author(s):  
Alireza Khoshkbar Sadeghi ◽  
Maryam Farbodi
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Polyvinyl Alcohol ◽  
Nanocomposite Film ◽  
Antibacterial Properties ◽  
Composition And Structure ◽  
Reinforcing Agent ◽  
Silver Nanocomposite ◽  
Thermal Stability Of

AbstractIn the present research, polyaniline is used as a conducting polymer and polyvinyl alcohol is also used as a biopolymer, because of its mechanical properties and suitable processability. Also, silver nanoparticles are considered as a reinforcing agent of thermal stability, mechanical and antibacterial properties to prepare polyaniline-polyvinyl alcohol-silver nanocomposite. The synthesis of polyaniline-polyvinyl alcohol composite and polyaniline-polyvinyl alcohol-silver nanocomposite is performed through addition of polyaniline and silver in polyvinyl alcohol solution. In order to review thermal, mechanical and antibacterial properties of synthesized composite and nanocomposites, components with different weight rates are used. The obtained results from thermogravimetric analysis (TGA) tests also indicate promotion of thermal stability of polyaniline-polyvinyl alcohol-silver nanocomposite compared with pure polyvinyl alcohol in temperatures above 400°C. The results of Fourier-transform infrared (FTIR) spectroscopy revealed the presence of polyaniline, polyvinyl alcohol and silver in the structure of polyaniline-polyvinyl alcohol-silver triple nanocomposite film. The obtained results from a review of antibacterial properties showed that polyaniline-polyvinyl alcohol-silver nanocomposites have antibacterial effects on two different types of Gram-positive and Gram-negative bacteria. The obtained results from a review of mechanical properties of nanocomposites showed that the greatest value of tensile strength (13.8 MPa) belonged to polyaniline-polyvinyl alcohol-silver (88%/9%/3% w/w) nanocomposites. Therefore, this is determined as an optimal triple nanocomposite. In addition, scanning electron microscopy (SEM) coupled with an energy dispersive X-ray (EDX) system was used to characterize the composition and structure of polyaniline-polyvinyl alcohol-silver nanocomposite film.

Food Grade Bioplastic Based on Corn Starch with Banana Pseudostem Fibre/Bacterial Cellulose Hybrid Filler

2014 ◽  
Vol 997 ◽  
pp. 158-168 ◽  
Author(s):  
Heri Hermansyah ◽  
Rena Carissa ◽  
Merisa Bestari Faiz ◽  
Priscilla Deni
Keyword(s):  
Mechanical Properties ◽  
Mechanical Strength ◽  
Bacterial Cellulose ◽  
Corn Starch ◽  
Transmission Rate ◽  
Barrier Properties ◽  
Hybrid Filler ◽  
Food Grade ◽  
Soil Burial ◽  
Water Barrier

Food grade bioplastic has become a popular research topic these days. However, further studies are still required in order to develop bioplastic that has comparable mechanical and water barrier properties with synthetic plastic. In this research, to improve mechanical and water barrier properties of plant cellulose filled bioplastic, bacterial cellulose is added to create hybrid filler with banana pseudostem fibre in glycerol plasticized corn starch matrix. The filler banana pseudostem fibre and bacterial cellulose were first dispersed in mixture of glycerol and distilled water, starch was added and mixture was heated until gelatinization occured. The mixture was then casted and dried in oven. Research proved that 10wt% against starch mass was an optimum filler composition, which resulted in the highest mechanical strength of bioplastic. The utilization of hybrid filler showed a decrease in mechanical strength compared with bioplastic with single filler. The ratio of banana pseudostem:bacterial cellulose compotition in hybrid filler that gave the best mechanical properties was 25:75 which resulted in tensile strength 4.599 MPa and modulus 174.1 MPa. Although the utilization of hybrid filler did not improve the mechanical properties of bioplastic, the addition of bacterial cellulose was proven to give positive effect to water barrier properties. Bioplastic filled with hybrid 10wt% banana pseudostem fibre and 35wt% bacterial cellulose had water vapour transmission rate 3.8958 g/m2/hour. The mechanical and water barrier properties of bioplastic was confirmed with SEM, FTIR, and XRD analysis. Soil burial test for 9 days proved that banana pseudostem filler decreased 6.9% of corn starch bioplastic biodegradation rate.

scholarly journals Mechanically Strong, Low Thermal Conductivity and Improved Thermal Stability Polyvinyl Alcohol–Graphene–Nanocellulose Aerogel

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 170
Author(s):  
Xiuya Wang ◽  
Pengbo Xie ◽  
Ke Wan ◽  
Yuanyuan Miao ◽  
Zhenbo Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Thermal Stability ◽  
Polyvinyl Alcohol ◽  
Low Density ◽  
Composite Aerogel ◽  
Ternary Composite ◽  
Low Thermal Conductivity ◽  
Good Thermal Stability ◽  
Composite Aerogels

Porous aerogel materials have advantages of a low density, low thermal conductivity and high porosity, and they have broad application prospects in heat insulation and building energy conservation. However, aerogel materials usually exhibit poor mechanical properties. Single-component aerogels are less likely to possess a good thermal stability and mechanical properties. It is necessary to prepare multiple-composite aerogels by reinforcement to meet practical application needs. In this experiment, a simple preparation method for polyvinyl alcohol (PVA)–graphene (GA)–nanocellulose (CNF) ternary composite aerogels was proposed. This is also the first time to prepare ternary composite aerogels by mixing graphene, nanocellulose and polyvinyl alcohol. A GA–CNF hydrogel was prepared by a one-step hydrothermal method, and soaked in PVA solution for 48 h to obtain a PVA–GA–CNF hydrogel. PVA–GA–CNF aerogels were prepared by freeze drying. The ternary composite aerogel has advantages of excellent mechanical properties, a low thermal conductivity and an improved thermal stability, because strong hydrogen bonds form between the PVA, GA and CNF. The composite aerogels were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffractometry, Brunauer–Emmett–Teller analysis, dynamic thermal analysis, thermogravimetry and thermal constant analysis to characterize the properties of the ternary composite aerogels. The lightweight, low-density and porous PVA–GA–CNF composite aerogels withstood 628 times their mass. The thermal conductivity of the composite aerogels was 0.044 ± 0.005 W/mK at room temperature and 0.045 ± 0.005 W/mK at 70 °C. This solid, low thermal conductivity and good thermal stability PVA–GA–CNF ternary composite aerogel has potential application in thermal insulation.

scholarly journals The Nanomechanical and Tribological Properties of Polyamide/Hydrotalcite Nanocomposites

Proceedings ◽  
2019 ◽  
Vol 29 (1) ◽  
pp. 70
Author(s):  
George Mihail Teodorescu ◽  
Zina Vuluga ◽  
Mihai Cosmin Corobea ◽  
Cristian Andi Nicoale ◽  
Augusta Raluca Gabor ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tribological Properties ◽  
Fire Resistance ◽  
Automotive Industry ◽  
High Performance ◽  
Scratch Resistance ◽  
Plastic Materials

In specific fields of the industry (e.g., aircraft and automotive industry), plastic materials with high performance (improved scratch resistance, fire resistance, thermal stability, and high mechanical properties) are required. [...]

scholarly journals Biopolymer Composites as an Alternative to Materials for the Production of Ecological Packaging

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 592
Author(s):  
Miroslawa Prochon ◽  
Oleksandra Dzeikala
Keyword(s):  
Thermal Stability ◽  
Polyvinyl Alcohol ◽  
Physicochemical Properties ◽  
Mechanical Strength ◽  
Optical Transmission ◽  
Casting Process ◽  
Cross Linking ◽  
Natural Sources ◽  
Biopolymer Composites ◽  
Selection Of

The problem of plastic waste has long been a concern for governments and society. However, huge amounts of plastic are still being released into the oceans and the environment. One possible solution is to replace plastics with materials that are more both biodecomposable and biodegradable. The most environmentally friendly materials are made of natural ingredients found in nature, although not all of them can be called biodegradable. In this study, we set out to create a new composite with functional properties that could replace commonly used disposable packaging. To ensure the competitiveness of our solution, we used inexpensive and readily available components, such as gelatin G HOOCCH2CH2C(R1)NHCOCH2NH2 (where R1 is a continuation of the peptide chain), polyvinyl alcohol PVA CH2CH(OH), and glycerin G HOCH2CH(CH2OH)O. The ingredients used in the research come from natural sources; however, they are chemically processed. Some of them, such as polyvinyl alcohol, for example, are biodegradable. With the appropriate selection of the components, in the casting process, the intermixed components made it possible to produce materials that were characterized by good physicochemical properties, including thermal stability, optical transmission of UV-Vis light, cross-linking density, and mechanical strength. The most favorable parameters of thermal stability were observed in casein-containing gelatine forms. The best cross-linking density was obtained in the case of gelatin–glycerine systems. Composite containing caseins distinguished by the highest resistance to flammability, increased thermal stability, flexibility, and greater hardness compared to other composites.

scholarly journals Lignocellulose Nanofibre Obtained from Agricultural Wastes of Tomato, Pepper and Eggplants Improves the Performance of Films of Polyvinyl Alcohol (PVA) for Food Packaging

Foods ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3043
Author(s):  
Isabel Bascón-Villegas ◽  
Mónica Sánchez-Gutiérrez ◽  
Fernando Pérez-Rodríguez ◽  
Eduardo Espinosa ◽  
Alejandro Rodríguez
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Antioxidant Activity ◽  
Polyvinyl Alcohol ◽  
Young’S Modulus ◽  
Food Packaging ◽  
Young's Modulus ◽  
Raw Material ◽  
Elongation At Break ◽  
Pre Treatment

Films formulated with polyvinyl alcohol (PVA) (synthetic biopolymer) were reinforced with lignocellulose nanofibres (LCNF) from residues of vegetable production (natural biopolymer). The LCNF were obtained by mechanical and chemical pre-treatment by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) and added to the polyvinyl alcohol (polymer matrix) with the aim of improving the properties of the film for use in food packaging. The mechanical properties, crystallinity, thermal resistance, chemical structure, antioxidant activity, water barrier properties and optical properties (transparency and UV barrier), were evaluated. In general, with the addition of LCNF, an improvement in the studied properties of the films was observed. In terms of mechanical properties, the films reinforced with 7% LCNF TEMPO showed the best results for tensile strength, Young’s modulus and elongation at break. At the same LCNF proportion, the thermal stability (Tmax) increased between 5.5% and 10.8%, and the antioxidant activity increased between 90.9% and 191.8%, depending on the raw material and the pre-treatment used to obtain the different LCNF. Finally, a large increase in UV blocking was also observed with the addition of 7% LCNF. In particular, the films with 7% of eggplant LCNF showed higher performance for Young’s modulus, elongation at break, thermal stability and UV barrier. Overall, results demonstrated that the use of LCNF generated from agricultural residues represents a suitable bioeconomy approach able to enhance film properties for its application in the development of more sustainable and eco-friendly food packaging systems.

Effect of water state and polymer chain motion on the mechanical properties of a bacterial cellulose and polyvinyl alcohol (BC/PVA) hydrogel

RSC Advances ◽  
2015 ◽  
Vol 5 (32) ◽  
pp. 25525-25531 ◽  
Author(s):  
Lifeng Li ◽  
Li Ren ◽  
Lin Wang ◽  
Sa Liu ◽  
Yongrou Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Polyvinyl Alcohol ◽  
Bacterial Cellulose ◽  
Polymer Chain ◽  
Effect Of Water ◽  
Water State ◽  
Pva Hydrogel

The effects of water state and polymer chain motion on the mechanical property of bacterial cellulose and a polyvinyl alcohol hydrogel.

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