scholarly journals Effectiveness of Silanization and Plasma Treatment in the Improvement of Selected Flax Fibers’ Properties

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3564
Author(s):  
Weronika Gieparda ◽  
Szymon Rojewski ◽  
Wanda Różańska
Keyword(s):  
Natural Fibers ◽  
Average Diameter ◽  
Plasma Modification ◽  
Linear Mass ◽  
Physical Methods ◽  
Flow Calorimeter ◽  
Flax Fibers ◽  
Before And After ◽  
Combustion Flow ◽  
Thermal Stability Of

The study investigated the effectiveness of the combination of chemical and physical methods of natural fibers’ modification. The long flax fibers were subjected to various types of modification. These were silanization, plasma modification and a combination of these methods. For the silanization process, two types of silanes were used: amino- and vinylsilane. The application of structurally different compounds allowed us to acquire knowledge about the effect of the modifier structure on its properties. Various properties of flax fibers were investigated, comparing the results before and after different modification processes. The flammability of prepared samples were tested by pyrolysis combustion flow calorimeter (PCFC). In the effect of the natural fibers’ modifications, flammability was reduced even by 30%. The thermal stability of modified fibers increased. The FTIR tests of the gases released during thermal degradation of the tested fibers allowed us to determine the important compounds and prove a lower degree of flax-fiber decomposition after modification. Flax fibers were also tested to evaluate their physical properties (linear mass, average diameter, aspect ratio and hygroscopicity). Changes in surface morphology were observed by scanning electron microscope (SEM). The properties of natural fibers improved significantly, thus contributing to an increase in their suitability for the use in composites.

scholarly journals Thermal Stability and Flammability Behavior of Poly(3-hydroxybutyrate) (PHB) Based Composites

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2239 ◽  
Author(s):  
Henri Vahabi ◽  
Laurent Michely ◽  
Ghane Moradkhani ◽  
Vahideh Akbari ◽  
Marianne Cochez ◽  
...  
Keyword(s):  
Thermal Stability ◽  
High Capacity ◽  
Digital Camera ◽  
Char Residue ◽  
Scanning Calorimetry ◽  
Flow Calorimeter ◽  
Burning Behavior ◽  
Dsc Analyses ◽  
Combustion Flow ◽  
Thermal Stability Of

A series of samples based on poly(3-hydroxybutyrate) (PHB) containing five different additives were prepared and their thermal stability and flammability were discussed. The samples first underwent flammability screening by using Pyrolysis Combustion Flow Calorimeter (PCFC) analyses. Then, four samples were selected for further investigations. PHB composites containing sepiolite (Sep.) inorganic nanofiller, and also organic ammonium polyphosphate (APP) were examined for flammability and thermal behavior using PCFC, thermogravimetric analysis (TGA), flame test, and Differential Scanning Calorimetry (DSC) analyses. Moreover, burning behavior of samples were captured on a digital camera to give a deeper sense of their flammability character for comparison. The results revealed a significant improvement of flammability and thermal stability of composites, particularly in the presence of sepiolite with respect to the value obtained for unfilled PHB. Regarding TGA results, the char residue yield was increased to ca. 20.0 wt.% in the presence of sepiolite, while 0.0 wt.% was observed for PHB. PCFC measurements uncovered higher performance of PHB-Sep. sample as signaled by 40% reduction in the peak of heat release rate with respect to PHB. According to observations, PHB-Sep. sample showed non-dripping behavior with high capacity of charring in the presence of Sep. in a vertical flame test.

Thermal Stability of Natural Fibers via Thermoset Coating for Application in Engineering Thermoplastics

2019 ◽  
Vol 809 ◽  
pp. 433-438 ◽  
Author(s):  
Natalie Vellguth ◽  
Tanja Rudeck ◽  
Madina Shamsuyeva ◽  
Franz Renz ◽  
Hans Josef Endres
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Epoxy Resin ◽  
Natural Fiber ◽  
Natural Fibers ◽  
Thermoplastic Composites ◽  
Processing Temperature ◽  
Scanning Calorimetry ◽  
Flax Fibers ◽  
Thermal Stability Of

An effective integration of natural fibers into engineering thermoplastics requires sufficient thermal stability of natural fibers during processing, since melting temperature of engineering thermoplastics lies above 200 °C. The aim of the work was to protect natural fibers from the heat of the molten thermoplastic via coating with a modified epoxy resin, thus enabling manufacture of natural fiber-reinforced engineering thermoplastic composites with minimized thermal degradation of the fibers. Processing temperature comprised the range of engineering thermoplastic polyamide 6 (PA6), which was 225 °C. Flax fabrics were spray coated with partially bio-based epoxy resin and incorporated via hot press technique into a PA6 matrix. The composite samples including spray coated flax fibers as well as the reference flax fibers without coating were characterized with regard to their mechanical properties, namely bending and tensile tests, thermal properties with differential scanning calorimetry (DSC) as well as thermogravimetric analysis (TGA) and optical via scanning electron microscopy (SEM) and computer tomography (CT). The results show that this approach enables manufacture of composites with reproducible mechanical properties, i.e. bending and tensile properties as well as enhanced thermal stabilities.

scholarly journals Single- and Multiwalled Carbon Nanotubes with Phosphorus Based Flame Retardants for Textiles

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
D. Wesolek ◽  
W. Gieparda
Keyword(s):  
Carbon Nanotubes ◽  
Thermal Stability ◽  
Multiwalled Carbon Nanotubes ◽  
Flame Retardants ◽  
Multiwalled Carbon ◽  
Textile Materials ◽  
Flow Calorimeter ◽  
Polyurethane Resin ◽  
Combustion Flow ◽  
Thermal Stability Of

Due to growing popularity of composites, modification methods to obtain the best properties are searched for. The aim of the study is to reduce the flammability of textile materials using nanocomposite polymer back-coating. Different types of carbon nanotubes (single- and multiwalled) and different phosphorus flame retardants (ammonium polyphosphates and melamine polyphosphate) were introduced into the resin and then the fabrics were covered by the obtained composites. Homogeneous dispersion of multiwalled carbon nanotubes in the polyurethane resin was obtained by sonification, which was confirmed by scanning electron microscopy. Flammability tests of fabrics coated by modified polyurethane resin were carried out using pyrolysis combustion flow calorimeter (PCFC) and thermal stability of textiles was evaluated. Also, organoleptic estimation of coatings was conducted (flexibility and fragility). The use of polymer nanocomposites with phophorus flame retardants as a back-coating for textiles effectively reduces flammability and improves thermal stability of the fabric. Furthermore, the synergistic effect beetwen carbon nanotubes and phosphorous compound occurs. The resulting coatings are flexible and do not crack or change the feel of fabrics.

scholarly journals Static and Dynamic Behavior of Polymer/Graphite Oxide Nanocomposites before and after Thermal Reduction

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1008
Author(s):  
Kiriaki Chrissopoulou ◽  
Krystalenia Androulaki ◽  
Massimiliano Labardi ◽  
Spiros H. Anastasiadis
Keyword(s):  
Graphite Oxide ◽  
Thermal Reduction ◽  
Polymer Chains ◽  
Solid Surfaces ◽  
Relaxation Processes ◽  
Thermal Transitions ◽  
Reduced Graphite Oxide ◽  
Before And After ◽  
Similarities And Differences ◽  
Thermal Stability Of

Nanocomposites of hyperbranched polymers with graphitic materials are investigated with respect to their structure and thermal properties as well as the dynamics of the polymer probing the effect of the different intercalated or exfoliated structure. Three generations of hyperbranched polyester polyols are mixed with graphite oxide (GO) and the favorable interactions between the polymers and the solid surfaces lead to intercalated structure. The thermal transitions of the confined chains are suppressed, whereas their dynamics show similarities and differences with the dynamics of the neat polymers. The three relaxation processes observed for the neat polymers are observed in the nanohybrids as well, but with different temperature dependencies. Thermal reduction of the graphite oxide in the presence of the polymer to produce reduced graphite oxide (rGO) reveals an increase in the reduction temperature, which is accompanied by decreased thermal stability of the polymer. The de-oxygenation of the graphite oxide leads to the destruction of the intercalated structure and to the dispersion of the rGO layers within the polymeric matrix because of the modification of the interactions between the polymer chains and the surfaces. A significant increase in the conductivity of the resulting nanocomposites, in comparison to both the polymers and the intercalated nanohybrids, indicates the formation of a percolated rGO network.

scholarly journals Polystyrene/Montmorillonite Nanocomposites: Study of the Morphology and Effects of Sonication Time on Thermal Stability

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Mashael Alshabanat ◽  
Amal Al-Arrash ◽  
Waffa Mekhamer
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Solution Method ◽  
Sonication Time ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Polystyrene Matrix ◽  
Before And After ◽  
Silicate Layers ◽  
Thermal Stability Of

Polymer nanocomposites of polystyrene matrix containing 10% wt of organo-montmorillonite (organo-MMT) were prepared using the solution method with sonication times of 0.5, 1, 1.5, and 2 hours. Cetyltrimethylammonium bromide (CTAB) is used to modify the montmorillonite clay after saturating its surface with Na+ions. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the montmorillonite before and after modification by CTAB. The prepared nanocomposites were characterized using the same analysis methods. These results confirm the intercalation of PS in the interlamellar spaces of organo-MMT with a very small quantity of exfoliation of the silicate layers within the PS matrix of all samples at all studied times of sonication. The thermal stability of the nanocomposites was measured using thermogravimetric analysis (TGA). The results show clear improvement, and the effects of sonication time are noted.

scholarly journals PLA Composites Reinforced with Flax and Jute Fibers—A Review of Recent Trends, Processing Parameters and Mechanical Properties

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2373 ◽  
Author(s):  
Usha Kiran Sanivada ◽  
Gonzalo Mármol ◽  
F. P. Brito ◽  
Raul Fangueiro
Keyword(s):  
Natural Fibers ◽  
High Strength ◽  
Processing Parameters ◽  
Economic Benefits ◽  
Synthetic Fibers ◽  
Flax Fibers ◽  
Structural Applications ◽  
Technical Features ◽  
Economic Price ◽  
Physical And Chemical

Multiple environmental concerns such as garbage generation, accumulation in disposal systems and recyclability are powerful drivers for the use of many biodegradable materials. Due to the new uses and requests of plastic users, the consumption of biopolymers is increasing day by day. Polylactic Acid (PLA) being one of the most promising biopolymers and researched extensively, it is emerging as a substitute for petroleum-based polymers. Similarly, owing to both environmental and economic benefits, as well as to their technical features, natural fibers are arising as likely replacements to synthetic fibers to reinforce composites for numerous products. This work reviews the current state of the art of PLA compounds reinforced with two of the high strength natural fibers for this application: flax and jute. Flax fibers are the most valuable bast-type fibers and jute is a widely available plant at an economic price across the entire Asian continent. The physical and chemical treatments of the fibers and the production processing of the green composites are exposed before reporting the main achievements of these materials for structural applications. Detailed information is summarized to understand the advances throughout the last decade and to settle the basis of the next generation of flax/jute reinforced PLA composites (200 Maximum).

scholarly journals Tensile Behavior and Diffusion of Moisture through Flax Fibers by Desorption Method

2019 ◽  
Vol 11 (13) ◽  
pp. 3558 ◽  
Author(s):  
Swarda S. Radkar ◽  
Ali Amiri ◽  
Chad A. Ulven
Keyword(s):  
Diffusion Coefficients ◽  
Natural Fibers ◽  
Woven Fabrics ◽  
Tensile Behavior ◽  
Flax Fiber ◽  
Additional Absorption ◽  
Flax Fibers ◽  
Diffusion Rates ◽  
Desorption Method ◽  
And Diffusion

There has been a substantial increase in the usage of natural fibers and biodegradable polymers in composite materials due to the recent focus on sustainability of materials. Flax fibers have exhibited higher mechanical properties compared to most other natural fibers available. However, one of the major challenges faced in the use of flax fiber is its hydrophilicity. In this study, the tensile behavior of flax fiber tows removed from commercially available woven fabrics were investigated at different moisture levels. The breaking tenacity of fiber tows was shown to increase with an increase in moisture content of up to 25%. After this point, additional absorption of moisture resulted in a decrease of fiber tenacity. In addition, the diffusion process through flax fiber mat with different areal densities was investigated and the diffusion coefficients were determined using the desorption curves. Diffusion rates were not found to significantly change with varying areal densities of 200 to 400 gsm, but were significantly different when exposed to temperatures of 55 °C versus 80 °C.

Optimization of Chitosan/PVA Concentration in Fabricating Nanofibers Membrane and its Prospect as Air Filtration

2017 ◽  
Vol 901 ◽  
pp. 20-25 ◽  
Author(s):  
Himayatus Shalihah ◽  
Ahmad Kusumaatmaja ◽  
Ari Dwi Nugraheni ◽  
Kuwat Triyana
Keyword(s):  
Electrospun Fiber ◽  
Chemical Compounds ◽  
Average Diameter ◽  
Air Filtration ◽  
Maximum Condition ◽  
Chemical Absorption ◽  
Fiber Mats ◽  
Before And After ◽  
Porosity Percentage ◽  
Scanning Electron

Chitosan/polyvinyl-alcohol (Chitosan/PVA) based nanofibers were successfully produced using electrospinning machine and investigated their application as air filtration. Firstly, 2 wt% chitosan was dissolved to 1 wt% acetic acid followed by mixing with PVA solution to produce fiber mats or membrane. Secondly, the morphology and diameter of the electrospun fiber were analyzed by using a scanning electron microscopy (SEM), while the chemical compounds in the membrane were characterized using Fourier transform infrared spectroscopy (FTIR). It was found that the conductivity of solution increased by the concentration of chitosan. Meanwhile, the average diameter and percentage of porosity decreased due to the upsurge of the conductivity of the solution. The average diameter of PVA 13 wt% was and the percentage of porosity were 50.32%. The maximum condition of chitosan/PVA was obtained at 20/80 wt%, in line with the average of fiber diameters and the percentage of porosity were 25.32%. Physicochemical properties of chitosan/PVA solution, such as conductivity, morphology, and chemical absorption were investigated before and after the air filtration. The porosity percentage of PVA 13wt% after air filtration changed to 35.85% and the percentage of porosity of chitosan/PVA 20/80 became 25.32%. Remarkable absorption peaks of PVA 13wt% exhibited and - shifted after the air filtration test, it was indicating that functional groups had been reduced. The chemical absorption of chitosan/PVA 20/80 wt% showed at the the region then disappeared after the air filtration test.

Effect of Alkali and Silane Treatment on the Thermal Stability of Hemp Fibers as Reinforcement in Composite Structures

2011 ◽  
Vol 415-417 ◽  
pp. 666-670 ◽  
Author(s):  
Na Lu ◽  
Shubhashini Oza ◽  
Ian Ferguson
Keyword(s):  
Thermal Stability ◽  
Composite Structures ◽  
Natural Fiber ◽  
Alkali Treatment ◽  
Thermo Gravimetric Analysis ◽  
Natural Fibers ◽  
Gravimetric Analysis ◽  
Silane Treatment ◽  
Hemp Fibers ◽  
Thermal Stability Of

Natural fiber reinforced composites are being used as reinforcement material in composite system due to their positive environmental benefits. Added to that, natural fibers offer advantages such as low density, low cost, good toughness, high specific strength, relatively non-abrasive and wide availability. However, the low thermal stability of natural fibers is one of the major challenges to increase their use as reinforcing component. In this study, a thorough investigation has been done to compare the effect of two chemical treatment methods on the thermal stability of hemp fibers. 5wt% sodium hydroxide and 5wt% triethoxyvinylsilane was used for the treatment of hemp fibers. Fourier transform infrared spectroscopy, scanning electron microscopy and thermo gravimetric analysis were used for characterization of untreated and treated fiber. The results indicated that 24 hours alkali treatment and 3 hours silane treatment time enhanced the thermal stability of the hemp fiber. However, alkali treatment shows better improvement compared to silane treatment.

Morphological, thermal and optical studies of jute-reinforced PbSrCaCuO–polypropylene composite

2016 ◽  
Vol 30 (31) ◽  
pp. 1650379
Author(s):  
Reenu Jacob ◽  
Jayakumari Isac
Keyword(s):  
Raw Materials ◽  
Natural Fibers ◽  
Ceramic Matrix ◽  
Ceramic Composites ◽  
Jute Fiber ◽  
Optical Studies ◽  
New Research ◽  
Tga And Dsc ◽  
Thermal Stability Of ◽  
Modern Technologies

New research with modern technologies has always grabbed substantial attention. Conservation of raw materials like natural fibers has helped composite world to explore eco-friendly components. The aim of this paper is to study the potential of jute fiber-reinforced ceramic polymers. Alkali-treated jute fiber has been incorporated in a polypropylene ceramic matrix at different volume fractions. The morphological, thermal and optical studies of jute-reinforced ceramic Pb2Sr2CaCu2O9 (PbSrCaCuO) are studied. Morphological results evidently demonstrate that when the polypropylene ceramic matrix is reinforced with jute fiber, interfacial interaction between the varying proportions of the jute fiber and ceramic composite takes place. TGA and DSC results confirm the enhancement in the thermal stability of ceramic composites reinforced with jute fiber. The UV analysis of the composite gives a good quality measure on the optical properties of the new composite prepared.

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