Special Issue "Advances in Natural Fiber Reinforced Polymer and Geopolymer Composites: Synthesis, Applications and Future Directions "

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

Deadline for manuscript submissions: closed (31 March 2020).

Special Issue Editor

Prof. Dr. It-Meng (Jim) Low
Website
Guest Editor
Department of Applied Physics, Curtin University, GPO Box U1987, Perth WA 6845, Australia
Interests: natural fiber reinforced composites; advanced ceramics; nanomaterials; photocatalytic materials; novel materials
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

There is an increasing commitment in the use of alternative eco-friendly natural reinforcements to produce advanced composites due to the imposition of strict environmental regulations and the depletion of petroleum resources. These natural fillers or fibres, such as sisal, coir, basalt, hemp, flax, and wool offer great renewability, biodegradability, abundance, cost effectiveness, and low specific gravity as opposed to synthetic fibres, such as glass and carbon. In addition, the composites and building industries have realised the enormous advantages of their composites by virtue of better functional or structural properties over synthetic counterparts despite not having relatively high mechanical performance. For instance, geopolymers have recently become a promising ecological alternative to the traditional cementitious material. They are cost-effective, environmentally friendly, and their production involves a relatively small amount of energy. They also have relatively good compressive strength, durability, and thermal properties, being highly resistant to flame and heat. However, geopolymers have relatively low tensile and flexural strength, which limits their use in many areas. The mechanical properties of geopolymers can be significantly improved by reinforcement with natural fibers. The resultant polymer and inorganic polymer composites are significantly better than those of traditional materials, and they are fueling the growing demand for natural fibers in various industries, such as automotive, building, and construction.

The popular research theme for composites with natural reinforcements generally covers polymer composites, geopolymer composites, fiber surface modification for the optimization of mechanical properties, and processing of natural, renewable, and biodegradable reinforcements. This Special Issue aims to provide a platform for sharing the latest advances in the synthesis, characterization, and mechanical properties of polymers and geopolymers reinforced with natural fibers such as pulp-fiber, cotton, sisal, flax, and hemp. The influence of adding various natural fibers on the mechanical properties of these composites will be discussed. Potential applications, challenges, and future directions of these composites shall be highlighted and addressed.

It is our pleasure to invite you to submit a manuscript to this Special Issue. Full papers, communications, and reviews that cover all aspects (i.e., synthesis–structure–property relationships, applications, and future directions) of polymer and geopolymer composites reinforced with natural fibers are all welcome.

The topics of interest include but are not limited to:

  • Materials for reinforcements in composites;
  • Durability, permeability, and fatigue life;
  • Interfacial debonding, matrix cracking, and damage evolution;
  • Characterizing and modeling reinforcements in composites;
  • Properties of composite reinforcements;
  • Structures for reinforcements in composites.

Prof. Dr. It-Meng (Jim) Low
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

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.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Natural fibers
  • Polymer
  • Geopolymer
  • Durability
  • Damage tolerance
  • Mechanical properties
  • Composite materials
  • Interfacial properties
  • Fiber surface modification
  • Renewable reinforcements

Published Papers (6 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Open AccessArticle
Phenolic Resin Foam Composites Reinforced by Acetylated Poplar Fiber with High Mechanical Properties, Low Pulverization Ratio, and Good Thermal Insulation and Flame Retardant Performance
Materials 2020, 13(1), 148; https://doi.org/10.3390/ma13010148 - 31 Dec 2019
Abstract
Phenolic foam composites (PFs) are of substantial interest due to their uniform closed-cell structure, low thermal conductivity, and good thermal insulation performance. However, their disadvantages of a high pulverization rate and poor mechanical properties restrict their application in building exterior insulation. Therefore, the [...] Read more.
Phenolic foam composites (PFs) are of substantial interest due to their uniform closed-cell structure, low thermal conductivity, and good thermal insulation performance. However, their disadvantages of a high pulverization rate and poor mechanical properties restrict their application in building exterior insulation. Therefore, the toughening of these composites is necessary. In this paper, poplar fiber was treated with an acetylation reagent, and the acetylated fiber was used to prepare modified phenolic foams (FTPFs); this successfully solved the phenomenon of the destruction of the foam structure due to the agglomeration of poplar fiber in the resin substrate. The foam composites were comprehensively evaluated via the characterization of their chemical structures, surface morphologies, mechanical properties, thermal conductivities, and flame retardant properties. It was found that the compressive strength and compressive modulus of FTPF-5% respectively increased by 28.5% and 37.9% as compared with those of PF. The pulverization ratio was reduced by 32.3%, and the thermal insulation performance and flame retardant performance (LOI) were improved. Compared with other toughening methods for phenolic foam composites, the phenolic foam composites modified with surface-compatibilized poplar fiber offer a novel strategy for the value-added utilization of woody fiber, and improve the toughness and industrial viability of phenolic foam. Full article
Show Figures

Graphical abstract

Open AccessArticle
Effect of Nanosilica on Mechanical Properties and Microstructure of PVA Fiber-Reinforced Geopolymer Composite (PVA-FRGC)
Materials 2019, 12(21), 3624; https://doi.org/10.3390/ma12213624 - 04 Nov 2019
Abstract
This paper presents the effects of various nanosilica (NS) contents on the mechanical properties of polyvinyl alcohol (PVA) fiber-reinforced geopolymer composites (PVA-FRGC). Microstructure analysis with X-ray diffraction (XRD) and scanning electron microscopy (SEM) was used to characterize the geopolymer composites. The results showed [...] Read more.
This paper presents the effects of various nanosilica (NS) contents on the mechanical properties of polyvinyl alcohol (PVA) fiber-reinforced geopolymer composites (PVA-FRGC). Microstructure analysis with X-ray diffraction (XRD) and scanning electron microscopy (SEM) was used to characterize the geopolymer composites. The results showed that the mechanical properties in terms of compressive strength, impact strength, and flexural behavior were improved due to the addition of NS to the PVA-FRGC. The optimum NS content was 1.0 to 2.0 wt%, which exhibited highest improvement in the above mechanical properties. Microstructure analysis showed that the addition of NS up to an optimum level densified the microstructure of the matrix as well as the PVA fiber–geopolymer matrix interface. Full article
Show Figures

Figure 1

Open AccessArticle
Effect of Hygrothermal Aging and Surface Treatment on the Dynamic Mechanical Behavior of Flax Fiber Reinforced Composites
Materials 2019, 12(15), 2376; https://doi.org/10.3390/ma12152376 - 25 Jul 2019
Cited by 1Correction
Abstract
The recent developments of FRP (fiber reinforced polymer) are towards the growth and usage of natural FRP in the field of engineering due to both environmental and economic benefits. Flax fiber is one of the most commonly used natural fibers. One of the [...] Read more.
The recent developments of FRP (fiber reinforced polymer) are towards the growth and usage of natural FRP in the field of engineering due to both environmental and economic benefits. Flax fiber is one of the most commonly used natural fibers. One of the critical factors affecting the mechanical behavior of FFRP (flax fiber reinforced polymer) is hygrothermal aging. Some experimental works have been conducted to investigate the effect of hydrothermal aging on static behavior of FFRP. However, fewer efforts have been made to study its damping properties after hydrothermal aging. In this paper, the effect of surface treatment (including alkalization, silanization, acetylation and alkali-silanization) on dynamic mechanical behavior of FFRP under hygrothermal aging is studied. The results show that water resistance and damping properties of FFRP are improved after surface treatment. The acetylation treated FFRP exhibits excellent damping performance among all treated specimens. Full article
Show Figures

Figure 1

Open AccessArticle
Effect of CNT Contents on the Microstructure and Properties of CNT/TiMg Composites
Materials 2019, 12(10), 1620; https://doi.org/10.3390/ma12101620 - 17 May 2019
Abstract
Carbon nanotubes (CNTs), dispersed in absolute ethanol, were evenly mixed into Ti/MgH2 powders by wet milling. Then, we applied the vacuum hot-pressed sinteringmethod to the CNTs/TiMg composite materials. An optical microscope (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive [...] Read more.
Carbon nanotubes (CNTs), dispersed in absolute ethanol, were evenly mixed into Ti/MgH2 powders by wet milling. Then, we applied the vacuum hot-pressed sinteringmethod to the CNTs/TiMg composite materials. An optical microscope (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and a field emission scanning electron microscope (FESEM) were used for the microstructure observation and phase analysis of samples. The mechanical properties were measured via the micro-vickers hardness. The results show that the main phases in the composites were Ti, Mg and C. Meanwhile, a small amount of Ti-Mg solid solution phase was also found. The cross-section morphology of the composites shows that the melted magnesium fills the grain interface during extrusion and that the composites have a better compactness.The microstructures of the composites have been greatly refined as the CNT contents increased. The structure of the composites was further refined when 0.5 wt.% CNTs were added. The fracture surface is obviously a ductile fracture. The microhardness increases obviously with the CNT content increasing. When the content of the CNTs is 1.0 wt.%, the microhardness of the composites reaches 232 HV, which is 24% higher than that of the matrix. Full article
Show Figures

Figure 1

Open AccessArticle
Comparison of Self-Etching Ceramic Primer and Conventional Silanization to Bond Strength in Cementation of Fiber Reinforced Composite Post
Materials 2019, 12(10), 1585; https://doi.org/10.3390/ma12101585 - 15 May 2019
Abstract
Various mechanical and chemical surface treatments have been proposed to improve the retention of fiber-reinforced composite post (FRCP), but the results are still controversial. The bond strength and durability of a self-etching ceramic primer, which was recently released as an alternative to etching [...] Read more.
Various mechanical and chemical surface treatments have been proposed to improve the retention of fiber-reinforced composite post (FRCP), but the results are still controversial. The bond strength and durability of a self-etching ceramic primer, which was recently released as an alternative to etching and silane, are not yet known. This study aimed to compare and evaluate the push-out bond strength of different surface treatments of FRCPs after an artificial aging procedure. Four groups (n = 10) were established to evaluated FRCP surface treatments (dentin adhesive bonding; silane and adhesive bonding; hydrofluoric acid, silane and adhesive bonding; and a self-etching ceramic primer). They were bonded with dual-curing rein cement (Multilink N) and stored in distilled water at 37 °C for 30 days, then thermal cycled for 7500 cycles. After being sectioned into 1 mm thickness, each coronal and apical part was evaluated for its the push-out bond strength by a universal testing machine. Each debonded specimen was observed by an optical microscope and divided according to the failure modes. The results showed that silane treatment significantly improved push-out bond strength, but the self-etching ceramic primer did not do so. Additional hydrofluoric acid treatment or the adhesive bonding agent alone did not significantly improve the retention of FRCPs. Cohesive failure of the luting material was found most frequently in all groups. Full article
Show Figures

Figure 1

Open AccessArticle
Influence of Nano Silica Particles on Durability of Flax Fabric Reinforced Geopolymer Composites
Materials 2019, 12(9), 1459; https://doi.org/10.3390/ma12091459 - 06 May 2019
Cited by 5
Abstract
The durability of natural fibres as reinforcement in geopolymer composites continues to be a matter of concern due to the alkalinity of activators of geopolymer matrices. The alkaline environment is the main reason for natural fibres degradation in cementitious matrices. This paper presents [...] Read more.
The durability of natural fibres as reinforcement in geopolymer composites continues to be a matter of concern due to the alkalinity of activators of geopolymer matrices. The alkaline environment is the main reason for natural fibres degradation in cementitious matrices. This paper presents the influence of nano silica (NS) on the durability and mechanical performance of geopolymer composites that are reinforced with flax fabric (FF). The durability investigations were conducted after the storage of samples at ambient temperature for 32 weeks. The study revealed that the addition of nano silica has a positive influence on the physical and mechanical properties of these composites. The presence of NS accelerated the geopolymeric reaction and lowered the alkalinity of the system, thus reducing the degradation of flax fibres. Full article
Show Figures

Figure 1

Back to TopTop