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Advances in Natural Fibers and Polymers

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Biomaterials".

Deadline for manuscript submissions: closed (31 December 2020) | Viewed by 51001

Special Issue Editor


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Guest Editor
Development and Product Innovation, Universitat de Girona, Girona, Spain
Interests: micromechanics; natural fiber composites; innovation; product design; nanofibers; green composites; nanocomposites
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The Special Issue aims to provide a forum for the discussion about the recent advances in the use of natural fibres from wood or annual plant strands, virgin or recycled from the textile industries as reinforcement, or filler material for composite materials, based on bio-based or biodegradable matrices.

The scope of the Issue includes basic research on the chemical structure of the composites and its interface, as well as the applied research on the mechanical and micromechanical properties of the materials. The Issue also includes studies on the life cycle assessment or environmental impact of the composites.

Dr. Francesc Xavier Espinach
Guest Editor

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

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Keywords

  • Annual plants
  • Recycled strands
  • Natural fiber composites
  • Life cycle assessment
  • Mechanical properties
  • Interphase
  • Micromechanics
  • Biodegradable matrices
  • Bio-based polymers

Published Papers (16 papers)

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Editorial

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4 pages, 173 KiB  
Editorial
Advances in Natural Fibers and Polymers
by Francesc X. Espinach
Materials 2021, 14(10), 2607; https://doi.org/10.3390/ma14102607 - 17 May 2021
Cited by 13 | Viewed by 1982
Abstract
The use of natural fibers as reinforcement for polymer-based composites has been attracting the interest of the scientific community for a long time [...] Full article
(This article belongs to the Special Issue Advances in Natural Fibers and Polymers)

Research

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15 pages, 4260 KiB  
Article
Conductive Regenerated Cellulose Fibers for Multi-Functional Composites: Mechanical and Structural Investigation
by Zainab Al-Maqdasi, Roberts Joffe, Ayoub Ouarga, Nazanin Emami, Shailesh Singh Chouhan, Anton Landström and Abdelghani Hajlane
Materials 2021, 14(7), 1746; https://doi.org/10.3390/ma14071746 - 01 Apr 2021
Cited by 5 | Viewed by 2069
Abstract
Regenerated cellulose fibers coated with copper via electroless plating process are investigated for their mechanical properties, molecular structure changes, and suitability for use in sensing applications. Mechanical properties are evaluated in terms of tensile stiffness and strength of fiber tows before, during and [...] Read more.
Regenerated cellulose fibers coated with copper via electroless plating process are investigated for their mechanical properties, molecular structure changes, and suitability for use in sensing applications. Mechanical properties are evaluated in terms of tensile stiffness and strength of fiber tows before, during and after the plating process. The effect of the treatment on the molecular structure of fibers is investigated by measuring their thermal stability with differential scanning calorimetry and obtaining Raman spectra of fibers at different stages of the treatment. Results show that the last stage in the electroless process (the plating step) is the most detrimental, causing changes in fibers’ properties. Fibers seem to lose their structural integrity and develop surface defects that result in a substantial loss in their mechanical strength. However, repeating the process more than once or elongating the residence time in the plating bath does not show a further negative effect on the strength but contributes to the increase in the copper coating thickness, and, subsequently, the final stiffness of the tows. Monitoring the changes in resistance values with applied strain on a model composite made of these conductive tows show an excellent correlation between the increase in strain and increase in electrical resistance. These results indicate that these fibers show potential when combined with conventional composites of glass or carbon fibers as structure monitoring devices without largely affecting their mechanical performance. Full article
(This article belongs to the Special Issue Advances in Natural Fibers and Polymers)
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20 pages, 7019 KiB  
Article
Reinforcing Mechanisms of Coir Fibers in Light-Weight Aggregate Concrete
by Xiaoxiao Zhang, Leo Pel, Florent Gauvin and David Smeulders
Materials 2021, 14(3), 699; https://doi.org/10.3390/ma14030699 - 02 Feb 2021
Cited by 14 | Viewed by 2811
Abstract
Due to the requirement for developing more sustainable constructions, natural fibers from agricultural wastes, such as coir fibers, have been increasingly used as an alternative in concrete composites. However, the influence of coir fibers on the hydration and shrinkage of cement-based materials is [...] Read more.
Due to the requirement for developing more sustainable constructions, natural fibers from agricultural wastes, such as coir fibers, have been increasingly used as an alternative in concrete composites. However, the influence of coir fibers on the hydration and shrinkage of cement-based materials is not clear. In addition, limited information about the reinforcing mechanisms of coir fibers in concrete can be found. The goal of this research is to investigate the effects of coir fibers on the hydration reaction, microstructure, shrinkages, and mechanical properties of cement-based light-weight aggregate concrete (LWAC). Treatments on coir fibers, namely Ca(OH)2 and nano-silica impregnation, are applied to further improve LWAC. Results show that leachates from fibers acting as a delayed accelerator promote cement hydration, and entrained water by fibers facilitates cement hydration during the whole process. The drying shrinkage of LWAC is increased by adding fibers, while the autogenous shrinkage decreases. The strength and toughness of LWAC are enhanced with fibers. Finally, three reinforcement mechanisms of coir fibers in cement composites are discussed. Full article
(This article belongs to the Special Issue Advances in Natural Fibers and Polymers)
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17 pages, 5921 KiB  
Article
Preparation and Characterisation of Waste Poultry Feathers Composite Fibreboards
by Riko Šafarič, Lidija Fras Zemljič, Miroslav Novak, Bogdan Dugonik, Božidar Bratina, Nenad Gubeljak, Silvester Bolka and Simona Strnad
Materials 2020, 13(21), 4964; https://doi.org/10.3390/ma13214964 - 04 Nov 2020
Cited by 22 | Viewed by 3931
Abstract
The growth of poultry meat production is increasing industrial waste quantities every year. Feathers represent a huge part of the waste, and international directives and restrictions prevent landfilling of such biodegradable materials with high burning values. Furthermore, with their unique properties, poultry waste [...] Read more.
The growth of poultry meat production is increasing industrial waste quantities every year. Feathers represent a huge part of the waste, and international directives and restrictions prevent landfilling of such biodegradable materials with high burning values. Furthermore, with their unique properties, poultry waste feathers are already a reliable resource for many byproducts, such as keratin extraction, fibres, hydrogel production, etc., all trying to achieve a high-added value. However, mass reduction of waste feathers into useful applications, such as development of alternative building materials, is also an important aspect. To take advantage of feathers’ thermal insulation capabilities, sound damping, and biodegradability, we worked towards mixing waste feathers with wood residues (wood shavings, dust, and mixed residues) for production of composite fibreboards, comparable to the market’s medium density fibreboards. The emphasis was to evaluate waste poultry feathers as the component of natural insulation composites, along with mixed waste wood residues, to improve their mechanical properties. Various composite fibreboards with different shares of wood and feathers were produced and tested for mechanical, thermal, and acoustic properties, and biodegradability, with comparison to typical particle boards on the market. The addition of waste feather fibres into the fibreboards’ structure improved thermal insulation properties, and the biodegradability of fibreboards, but decreased their bending strength. The sound transition acoustic loss results of the presented combination fibreboards with added feathers improved at mid and high frequencies. Finally, production costs are estimated based on small scale laboratory experiments of feather processing (cleaning and drying), with the assumption of cost reduction in cases of large industrial application. Full article
(This article belongs to the Special Issue Advances in Natural Fibers and Polymers)
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13 pages, 2652 KiB  
Article
Surface Activation of Polylactic Acid-Based Wood-Plastic Composite by Atmospheric Pressure Plasma Treatment
by Philipp Sauerbier, Robert Köhler, Gerrit Renner and Holger Militz
Materials 2020, 13(20), 4673; https://doi.org/10.3390/ma13204673 - 20 Oct 2020
Cited by 15 | Viewed by 2636
Abstract
Wood-plastic composite (WPC) based on a polylactic acid (PLA) matrix is a promising material since it is biobased, degradable, sustainable, and 3D printable. However, due to its coloring, visible layers after 3D-printing, and small build volumes of these printers, a coating or gluing [...] Read more.
Wood-plastic composite (WPC) based on a polylactic acid (PLA) matrix is a promising material since it is biobased, degradable, sustainable, and 3D printable. However, due to its coloring, visible layers after 3D-printing, and small build volumes of these printers, a coating or gluing of parts might be required. This study investigates the influence of a dielectric barrier discharge (DBD) plasma treatment of PLA-based WPC to activate the surface and improve, e.g., coating capabilities. X-ray photoelectron spectroscopy (XPS) measurements showed the oxidation of the surface due to the formation of carbonyl and carboxyl groups. Laser scanning microscopy revealed a surface roughening after the treatment. Contact angles of water and diiodomethane decreased significantly after the plasma treatment and the consecutively calculated surface free energy increased. Finally, two practical adhesion tests revealed an improvement of the applied acrylic dispersion coating’s adhesion to the WPC surface: The assigned cross-cut class improved, and the pull-off strength increased from 1.4 to 2.3 N/mm2. Full article
(This article belongs to the Special Issue Advances in Natural Fibers and Polymers)
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15 pages, 3343 KiB  
Article
Preparation and Properties of Microcrystalline Cellulose/Fish Gelatin Composite Film
by Ling Pan, Peng Li and Yubo Tao
Materials 2020, 13(19), 4370; https://doi.org/10.3390/ma13194370 - 30 Sep 2020
Cited by 23 | Viewed by 2526
Abstract
As a natural macromolecule-based biomaterial, fish gelatin is used in medical materials for its low pathogen infection risk. However, because of poor mechanical properties, its application has been limited. In this study, microcrystalline cellulose-reinforced fish gelatin (FG/MCC) composite films were prepared with a [...] Read more.
As a natural macromolecule-based biomaterial, fish gelatin is used in medical materials for its low pathogen infection risk. However, because of poor mechanical properties, its application has been limited. In this study, microcrystalline cellulose-reinforced fish gelatin (FG/MCC) composite films were prepared with a biological cross-linking agent (genipin) under ultrasonic treatment. SEM micrographs showed that the smooth microstructure of FG film became increasingly disordered with the addition of MCC. The infrared spectrum analysis (FTIR) demonstrated the existence of hydrogen bond interaction between MCC and FG. Compared with the pure FG film, the tensile strength (TS) and modulus of elasticity (MOE) of composite films with MCC were improved, and the elongation at break (EAB) and swelling ratios (SR) were decreased. Ultrasonic treatment could further improve TS, MOE, and SR. When the composite film was prepared with 15% MCC and treated with ultrasound, the TS and MOE increased by 115% and 227%, respectively, while the EAB decreased by 35% and the SR decreased by 4% in comparison with pure FG films. Thermo-gravimetric analysis (TGA) showed that the FG/MCC composite films were stable below 100 °C. The above results indicate that the FG/MCC films have optimistic application prospects in the biomedical field. Full article
(This article belongs to the Special Issue Advances in Natural Fibers and Polymers)
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17 pages, 3558 KiB  
Article
Thermal and Mechanical Characterization of Banana Fiber Reinforced Composites for Its Application in Injection Molding
by Dragan Kusić, Uroš Božič, Mario Monzón, Rubén Paz and Pablo Bordón
Materials 2020, 13(16), 3581; https://doi.org/10.3390/ma13163581 - 13 Aug 2020
Cited by 25 | Viewed by 3631
Abstract
Several natural materials and vegetable waste have relevant mechanical properties, mainly in its fiber format. Particularly, banana fiber (BF) provides a close behavior to the widely spread glass fibers, which places it in an advantageous position for use as a reinforcing material in [...] Read more.
Several natural materials and vegetable waste have relevant mechanical properties, mainly in its fiber format. Particularly, banana fiber (BF) provides a close behavior to the widely spread glass fibers, which places it in an advantageous position for use as a reinforcing material in plastic composites. This work characterizes the behavior of acrylonitrile butadiene styrene (ABS), high impact polystyrene (HIPS), and high density polyethylene (HDPE) reinforced with short fibers of bananas from the Canary Islands for its application in molding processes. Several thermal analyses (Thermal Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and Melt Flow Index (MFI)) and mechanical tests (tensile, flexural, impact, and Dynamic Mechanical Analysis (DMA)) were carried out in composites with different percentages of banana fiber. The thermal results show that the use of banana fiber is viable as a reinforcement in composites for injection molding processes and the mechanical tests indicate an increase in stiffness and an improvement in maximum flexural stress by increasing the fiber content in composites, so the banana fiber turns out to be a natural alternative for the reinforcement of injected plastic components. Full article
(This article belongs to the Special Issue Advances in Natural Fibers and Polymers)
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31 pages, 7100 KiB  
Article
Comparative Analysis of Carbon, Ecological, and Water Footprints of Polypropylene-Based Composites Filled with Cotton, Jute and Kenaf Fibers
by Jerzy Korol, Aleksander Hejna, Dorota Burchart-Korol and Jan Wachowicz
Materials 2020, 13(16), 3541; https://doi.org/10.3390/ma13163541 - 11 Aug 2020
Cited by 34 | Viewed by 4334
Abstract
Composites containing natural fibers are considered environmentally friendly materials which is related to the reduced use of fossil fuels and the emission of carbon dioxide compared to petroleum-based polymers. Nevertheless, a complete evaluation of their environmental impact requires a broader view. This paper [...] Read more.
Composites containing natural fibers are considered environmentally friendly materials which is related to the reduced use of fossil fuels and the emission of carbon dioxide compared to petroleum-based polymers. Nevertheless, a complete evaluation of their environmental impact requires a broader view. This paper presents a carbon, ecological, and water footprints assessment of polypropylene-based composites filled with cotton, jute, and kenaf fibers based on a standardized European pallet (EUR-pallet) case study. Obtained results were compared with unmodified polypropylene and composite with glass fibers. Incorporation of 30 wt% of cotton, jute, and kenaf fibers into a polypropylene matrix reduced its carbon footprint by 3%, 18%, and 18%, respectively. Regarding the ecological footprint, an 8.2% and 9.4% reduction for jute and kenaf fibers were noted, while for cotton fibers, its value increased by 52%. For these footprints, the use of jute and kenaf fibers was more beneficial than glass fibers. Nevertheless, the application of natural fibers caused a 286%, 758%, and 891% drastic increase of water footprint of the final product, which was mainly affected by cultivation and irrigation of crops. Therefore, in a holistic view, the incorporation of natural fibers into the polypropylene matrix definitely cannot be impartially considered as an environmentally friendly solution. Full article
(This article belongs to the Special Issue Advances in Natural Fibers and Polymers)
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18 pages, 5425 KiB  
Article
Superiority of Cellulose Non-Solvent Chemical Modification over Solvent-Involving Treatment: Application in Polymer Composite (part II)
by Stefan Cichosz and Anna Masek
Materials 2020, 13(13), 2901; https://doi.org/10.3390/ma13132901 - 28 Jun 2020
Cited by 19 | Viewed by 2467
Abstract
The following article debates on the properties of cellulose-filled ethylene-norbornene copolymer (EN) composites. Natural fibers employed in this study have been modified via two different approaches: solvent-involving (S) and newly developed non-solvent (NS). The second type of the treatment is fully eco-friendly and [...] Read more.
The following article debates on the properties of cellulose-filled ethylene-norbornene copolymer (EN) composites. Natural fibers employed in this study have been modified via two different approaches: solvent-involving (S) and newly developed non-solvent (NS). The second type of the treatment is fully eco-friendly and was carried out in the planetary mill without incorporation of any additional, waste-generating substances. Composite samples have been investigated with the use of spectroscopic methods (FT-IR), differential scanning calorimetry (DSC), static mechanical analysis, and surface-free energy measurements. It has been proved that the possible filler-polymer matrix interaction changes may occur due to the performed modifications. The highest reinforcement was evidenced for the composite sample filled with cellulose treated via a NS approach—TS = (34 ± 2) MPa, Eb = (380 ± 20)%. Additionally, a surface free energy polar part exhibited a significant increase for the same type of modification. Consequently, this could indicate easier wetting of the material which may contribute to the degradation process enhancement. Successfully developed cellulose-filled ethylene-norbornene copolymer composite compromises the rules of green chemistry and sustainable development by taking an advantage of renewable natural resources. This bio-inspired material may become an eco-friendly alternative for commonly used polymer blends. Full article
(This article belongs to the Special Issue Advances in Natural Fibers and Polymers)
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18 pages, 3374 KiB  
Article
Polylactic Acid/Polycaprolactone Blends: On the Path to Circular Economy, Substituting Single-Use Commodity Plastic Products
by Marc Delgado-Aguilar, Rita Puig, Ilija Sazdovski and Pere Fullana-i-Palmer
Materials 2020, 13(11), 2655; https://doi.org/10.3390/ma13112655 - 10 Jun 2020
Cited by 29 | Viewed by 3548
Abstract
Circular economy comes to break the linear resource to waste economy, by introducing different strategies, two of them being: using material from renewable sources and producing biodegradable products. The present work aims at developing polylactic acid (PLA), typically made from fermented plant starch, [...] Read more.
Circular economy comes to break the linear resource to waste economy, by introducing different strategies, two of them being: using material from renewable sources and producing biodegradable products. The present work aims at developing polylactic acid (PLA), typically made from fermented plant starch, and polycaprolactone (PCL) blends, a biodegradable polyester, to study their potential to be used as substitutes of oil-based commodity plastics. For this, PLA/PCL blends were compounded in a batch and lab scale internal mixer and processed by means of injection molding. Tensile and impact characteristics were determined and compared to different thermoplastic materials, such as polypropylene, high density polyethylene, polystyrene, and others. It has been found that the incorporation of PCL into a PLA matrix can lead to materials in the range of 18.25 to 63.13 megapascals of tensile strength, 0.56 to 3.82 gigapascals of Young’s modulus, 12.65 to 3.27 percent of strain at maximum strength, and 35 to 2 kJ/m2 of notched impact strength. The evolution of the tensile strength fitted the Voigt and Reuss model, while Young’s modulus was successfully described by the rule of mixtures. Toughness of PLA was significantly improved with the incorporation of PCL, significantly increasing the energy required to fracture the specimens. Blends containing more than 20 wt% of PCL did not break when unnotched specimens were tested. Overall, it was found that the obtained PLA/PCL blends can constitute a strong and environmentally friendly alternative to oil-based commodity materials. Full article
(This article belongs to the Special Issue Advances in Natural Fibers and Polymers)
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16 pages, 2924 KiB  
Article
Superiority of Cellulose Non-Solvent Chemical Modification over Solvent-Involving Treatment: Solution for Green Chemistry (Part I)
by Stefan Cichosz and Anna Masek
Materials 2020, 13(11), 2552; https://doi.org/10.3390/ma13112552 - 03 Jun 2020
Cited by 9 | Viewed by 2842
Abstract
In the following article, a new approach of cellulose modification, which does not incorporate any solvents (NS), is introduced. It is compared for the first time with the traditional solvent-involving (S) treatment. The analysed non-solvent modification process is carried out in a planetary [...] Read more.
In the following article, a new approach of cellulose modification, which does not incorporate any solvents (NS), is introduced. It is compared for the first time with the traditional solvent-involving (S) treatment. The analysed non-solvent modification process is carried out in a planetary mill. This provides the opportunity for cellulose mechanical degradation, decreasing its size, simultaneously with ongoing silane coupling agent grafting. Fourier-transform infrared spectroscopy (FT-IR) indicated the possibility of intense cleavage of the glucose rings in the cellulose chains during the mechano-chemical treatment. This effect was proved with dynamic light scattering (DLS) results—the size of the particles decreased. Moreover, according to differential scanning calorimetry (DSC) investigation, modified samples exhibited decreased moisture content and a drop in the adsorbed water evaporation temperature. The performed research proved the superiority of the mechano-chemical treatment over regular chemical modification. The one-pot bio-filler modification approach, as a solution fulfilling green chemistry requirements, as well as compromising the sustainable development rules, was presented. Furthermore, this research may contribute significantly to the elimination of toxic solvents from cellulose modification processes. Full article
(This article belongs to the Special Issue Advances in Natural Fibers and Polymers)
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15 pages, 3188 KiB  
Article
Impact Properties and Water Uptake Behavior of Old Newspaper Recycled Fibers-Reinforced Polypropylene Composites
by David Hernández-Díaz, Ricardo Villar-Ribera, Francesc X. Espinach, Fernando Julián, Vicente Hernández-Abad and Marc Delgado-Aguilar
Materials 2020, 13(5), 1079; https://doi.org/10.3390/ma13051079 - 28 Feb 2020
Cited by 17 | Viewed by 2294
Abstract
Natural fiber-reinforced thermoplastic composites can be an alternative to mineral fiber-based composites, especially when economic and environment concerns are included under the material selection criteria. In recent years, the literature has shown how lignocellulosic fiber-reinforced composites can be used for a variety of [...] Read more.
Natural fiber-reinforced thermoplastic composites can be an alternative to mineral fiber-based composites, especially when economic and environment concerns are included under the material selection criteria. In recent years, the literature has shown how lignocellulosic fiber-reinforced composites can be used for a variety of applications. Nonetheless, the impact strength and the water uptake behavior of such materials have been seen as drawbacks. In this work, the impact strength and the water uptake of composites made of polypropylene reinforced with fibers from recycled newspaper have been researched. The results show how the impact strength decreases with the percentage of reinforcement in a similar manner to that of glass fiber-reinforced polypropylene composites as a result of adding a fragile phase to the material. It was found that the water uptake increased with the increasing percentages of lignocellulosic fibers due to the hydrophilic nature of such reinforcements. The diffusion behavior was found to be Fickian. A maleic anhydride was added as a coupling agent in order to increase the strength of the interface between the matrix and the reinforcements. It was found that the presence of such a coupling agent increased the impact strength of the composites and decreased the water uptake. Impact strengths of 21.3 kJ/m3 were obtained for a coupled composite with 30 wt % reinforcement contents, which is a value higher than that obtained for glass fiber-based materials. The obtained composites reinforced with recycled fibers showed competitive impact strength and water uptake behaviors in comparison with materials reinforced with raw lignocellulosic fibers. The article increases the knowledge on newspaper fiber-reinforced polyolefin composite properties, showing the competitiveness of waste-based materials. Full article
(This article belongs to the Special Issue Advances in Natural Fibers and Polymers)
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16 pages, 4537 KiB  
Article
Topography of the Interfacial Shear Strength and the Mean Intrinsic Tensile Strength of Hemp Fibers as a Reinforcement of Polypropylene
by David Hernández-Díaz, Ricardo Villar-Ribera, Fernando Julián, Quim Tarrés, Francesc X. Espinach and Marc Delgado-Aguilar
Materials 2020, 13(4), 1012; https://doi.org/10.3390/ma13041012 - 24 Feb 2020
Cited by 7 | Viewed by 2583
Abstract
The strength of the interphase between the reinforcements and the matrix has a major role in the mechanical properties of natural fiber reinforced polyolefin composites. The creation of strong interphases is hindered by the hydrophobic and hydrophilic natures of the matrix and the [...] Read more.
The strength of the interphase between the reinforcements and the matrix has a major role in the mechanical properties of natural fiber reinforced polyolefin composites. The creation of strong interphases is hindered by the hydrophobic and hydrophilic natures of the matrix and the reinforcements, respectively. Adding coupling agents has been a common strategy to solve this problem. Nonetheless, a correct dosage of such coupling agents is important to, on the one hand guarantee strong interphases and high tensile strengths, and on the other hand ensure a full exploitation of the strengthening capabilities of the reinforcements. The paper proposes using topographic profile techniques to represent the effect of reinforcement and coupling agent contents of the strength of the interphase and the exploitation of the reinforcements. This representation allowed identifying the areas that are more or less sensitive to coupling agent content. The research also helped by finding that an excess of coupling agent had less impact than a lack of this component. Full article
(This article belongs to the Special Issue Advances in Natural Fibers and Polymers)
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17 pages, 23022 KiB  
Article
The Effect of Filler Content on the Tensile Behavior of Polypropylene/Cotton Fiber and poly(vinyl chloride)/Cotton Fiber Composites
by Elsadig Mahdi and Aamir Dean
Materials 2020, 13(3), 753; https://doi.org/10.3390/ma13030753 - 06 Feb 2020
Cited by 47 | Viewed by 3228
Abstract
This paper investigates the effect of filler content on the mechanical properties of cotton fiber (CF) on the CF/PP and CF/PVC composites under quasi-static loading. For this purpose, experimental tensile tests were carried out on dog-bone specimens, cut out from hot and cold [...] Read more.
This paper investigates the effect of filler content on the mechanical properties of cotton fiber (CF) on the CF/PP and CF/PVC composites under quasi-static loading. For this purpose, experimental tensile tests were carried out on dog-bone specimens, cut out from hot and cold press molded square plates of different fiber weight contents. The results obtained show that the filler content appears to have a strong influence on mechanical energy absorption, and failure characteristics. It was also found that the stiffness for both sets of material increases with the addition of filler. On the other hand, the ductility for both sets of the material increases with the addition of filler. The microscopic morphology study indicates that CF/PP possesses a glossy surface appearance compared to CF/PVC, which possesses a porous surface. Micro-scale damage characteristics from tensile tests indicate that material experienced shear failure, matrix cracking, fiber breakage, fiber fracture, and fiber pullout. The phenomenon of matrix crazing experienced by CF/PP composites was also observed. Full article
(This article belongs to the Special Issue Advances in Natural Fibers and Polymers)
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16 pages, 4542 KiB  
Article
Experimental Analysis and Simulation of Novel Technical Textile Reinforced Composite of Banana Fibre
by Mario D. Monzón, Rubén Paz, Martí Verdaguer, Luis Suárez, Pere Badalló, Zaida Ortega and Noelia Diaz
Materials 2019, 12(7), 1134; https://doi.org/10.3390/ma12071134 - 07 Apr 2019
Cited by 18 | Viewed by 4005
Abstract
The use of natural fibres allows reducing environmental impact, due to their natural renewable origin and the lower energy needed for their production and processing. This work presents the mechanical characterization of a newly developed technical textile, with banana fibre treated by enzymes, [...] Read more.
The use of natural fibres allows reducing environmental impact, due to their natural renewable origin and the lower energy needed for their production and processing. This work presents the mechanical characterization of a newly developed technical textile, with banana fibre treated by enzymes, comparing experimental results with numerical simulation based on the definition of the unit cell at micromechanical level. The experimental test shows that the composite with the fabric of banana fibre presents worse mechanical behaviour than the one with commercial flax fibre. The presence of wool, necessary for producing the yarn, reduces the mechanical properties of the banana textile. The numerical simulation had an acceptable error compared with the experimental results, with a global average error of 9%, showing that the predictive modelling based on the multiscale method is suitable for the design process of this kind of composite. Full article
(This article belongs to the Special Issue Advances in Natural Fibers and Polymers)
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18 pages, 3599 KiB  
Article
Thermal, Mechanical, Viscoelastic and Morphological Properties of Poly(lactic acid) based Biocomposites with Potato Pulp Powder Treated with Waxes
by Maria Cristina Righetti, Patrizia Cinelli, Norma Mallegni, Carlo Andrea Massa, Laura Aliotta and Andrea Lazzeri
Materials 2019, 12(6), 990; https://doi.org/10.3390/ma12060990 - 26 Mar 2019
Cited by 22 | Viewed by 4080
Abstract
The thermal, mechanical and viscoelastic properties of biocomposites of poly(lactic acid) (PLA) with 20 wt.% of potato pulp powder were investigated. The potato pulp powder utilized is a byproduct from the production and extraction of starch. The results showed that the potato pulp [...] Read more.
The thermal, mechanical and viscoelastic properties of biocomposites of poly(lactic acid) (PLA) with 20 wt.% of potato pulp powder were investigated. The potato pulp powder utilized is a byproduct from the production and extraction of starch. The results showed that the potato pulp powder does not act as reinforcement, but as filler for PLA, due to an unfavorable aspect ratio and the irregular shape of the particles. In order to improve the mechanical response of the PLA/potato pulp powder biocomposites, surface treatment of the potato pulp particles with bio-based and petroleum-based waxes was investigated. This treatment was found to improve the properties of the biocomposites, enhancing the adhesion between the PLA based polymeric matrix and the potato pulp fibers. The best result is obtained with a petroleum-based wax, but also the bio-based waxes lead to good mechanical properties of the biocomposite. Thus, the addition to PLA of potato pulp powder, treated with waxes, appears a method able to (i) utilize and valorize an abundant agro-food biomass such as potato pulp, according to the principles of circular economy, (ii) favor the production of articles with properties valuable for practical applications, and (iii) reduce the cost of the final products, considering the relatively high cost of PLA. Full article
(This article belongs to the Special Issue Advances in Natural Fibers and Polymers)
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